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8,591,741	https://en.wikipedia.org/wiki/List%20of%20stars%20in%20Lynx	This is the list of notable stars in the constellation Lynx, sorted by decreasing brightness. See also List of stars by constellation References List Lynx	List of stars in Lynx	[ "Astronomy" ]	29	[ "Lists of stars by constellation", "Lynx (constellation)", "Constellations" ]
8,591,748	https://en.wikipedia.org/wiki/List%20of%20stars%20in%20Lyra	This is the list of notable stars in the constellation Lyra, sorted by decreasing brightness. See also List of stars by constellation References List Lyra	List of stars in Lyra	[ "Astronomy" ]	31	[ "Lists of stars by constellation", "Lyra", "Constellations" ]
8,591,753	https://en.wikipedia.org/wiki/List%20of%20stars%20in%20Mensa	This is the list of notable stars in the constellation Mensa, sorted by decreasing brightness. See also List of stars by constellation References List Mensa	List of stars in Mensa	[ "Astronomy" ]	31	[ "Lists of stars by constellation", "Mensa (constellation)", "Constellations" ]
8,591,756	https://en.wikipedia.org/wiki/List%20of%20stars%20in%20Microscopium	This is the list of notable stars in the constellation Microscopium, sorted by decreasing brightness. See also List of stars by constellation References List Microscopium	List of stars in Microscopium	[ "Astronomy" ]	35	[ "Lists of stars by constellation", "Microscopium", "Constellations" ]
8,591,759	https://en.wikipedia.org/wiki/List%20of%20stars%20in%20Monoceros	This is the list of notable stars in the constellation Monoceros, sorted by decreasing brightness. See also List of stars by constellation References List Monoceros	List of stars in Monoceros	[ "Astronomy" ]	33	[ "Lists of stars by constellation", "Monoceros", "Constellations" ]
8,591,764	https://en.wikipedia.org/wiki/List%20of%20stars%20in%20Musca	This is the list of notable stars in the constellation Musca, sorted by decreasing brightness. See also List of stars by constellation Notes References List Musca	List of stars in Musca	[ "Astronomy" ]	32	[ "Lists of stars by constellation", "Musca", "Constellations" ]
8,591,770	https://en.wikipedia.org/wiki/List%20of%20stars%20in%20Norma	This is the list of notable stars in the constellation Norma, sorted by decreasing brightness. See also List of stars by constellation References List Norma	List of stars in Norma	[ "Astronomy" ]	29	[ "Lists of stars by constellation", "Norma (constellation)", "Constellations" ]
8,591,772	https://en.wikipedia.org/wiki/List%20of%20stars%20in%20Octans	This is the list of notable stars in the constellation Octans, sorted by decreasing brightness. See also List of stars by constellation References List Octans	List of stars in Octans	[ "Astronomy" ]	31	[ "Lists of stars by constellation", "Octans", "Constellations" ]
8,591,776	https://en.wikipedia.org/wiki/List%20of%20stars%20in%20Ophiuchus	This is the list of notable stars in the constellation Ophiuchus, sorted by decreasing brightness. See also List of stars by constellation References List Ophiuchus	List of stars in Ophiuchus	[ "Astronomy" ]	35	[ "Lists of stars by constellation", "Ophiuchus", "Constellations" ]
8,591,778	https://en.wikipedia.org/wiki/List%20of%20stars%20in%20Orion	This is the list of notable stars in the constellation Orion, sorted by decreasing brightness. See also List of stars by constellation References List Orion	List of stars in Orion	[ "Astronomy" ]	29	[ "Lists of stars by constellation", "Constellations", "Orion (constellation)" ]
8,591,785	https://en.wikipedia.org/wiki/List%20of%20stars%20in%20Pavo	This is the list of notable stars in the constellation Pavo, sorted by decreasing brightness. See also List of stars by constellation References List Pavo	List of stars in Pavo	[ "Astronomy" ]	31	[ "Lists of stars by constellation", "Constellations", "Pavo (constellation)" ]
8,591,788	https://en.wikipedia.org/wiki/List%20of%20stars%20in%20Pegasus	This is the list of notable stars in the constellation Pegasus, sorted by decreasing brightness. See also List of stars by constellation References List Pegasus	List of stars in Pegasus	[ "Astronomy" ]	29	[ "Lists of stars by constellation", "Pegasus (constellation)", "Constellations" ]
8,591,792	https://en.wikipedia.org/wiki/List%20of%20stars%20in%20Perseus	This is the list of notable stars in the constellation Perseus, sorted by decreasing brightness. See also List of stars by constellation References List Perseus	List of stars in Perseus	[ "Astronomy" ]	33	[ "Perseus (constellation)", "Lists of stars by constellation", "Constellations" ]
8,591,795	https://en.wikipedia.org/wiki/List%20of%20stars%20in%20Phoenix	This is the list of stars in the constellation Phoenix. See also List of stars by constellation References List Phoenix	List of stars in Phoenix	[ "Astronomy" ]	23	[ "Lists of stars by constellation", "Phoenix (constellation)", "Constellations" ]
8,591,799	https://en.wikipedia.org/wiki/List%20of%20stars%20in%20Pictor	This is the list of notable stars in the constellation Pictor, sorted by decreasing brightness. See also List of stars by constellation References List Pictor	List of stars in Pictor	[ "Astronomy" ]	31	[ "Lists of stars by constellation", "Pictor", "Constellations" ]
8,591,805	https://en.wikipedia.org/wiki/List%20of%20stars%20in%20Pisces	This is the list of notable stars in the constellation Pisces, sorted by decreasing brightness. See also List of stars by constellation References List Pisces	List of stars in Pisces	[ "Astronomy" ]	33	[ "Lists of stars by constellation", "Pisces (constellation)", "Constellations" ]
8,591,812	https://en.wikipedia.org/wiki/List%20of%20stars%20in%20Piscis%20Austrinus	This is the list of notable stars in the constellation Piscis Austrinus, sorted by decreasing brightness. See also List of stars by constellation References List Piscis Austrinus	List of stars in Piscis Austrinus	[ "Astronomy" ]	39	[ "Piscis Austrinus", "Lists of stars by constellation", "Constellations" ]
8,591,814	https://en.wikipedia.org/wiki/List%20of%20stars%20in%20Puppis	This is the list of notable stars in the constellation Puppis, sorted by decreasing brightness. This constellation's Bayer designations (Greek-letter star names) were given while it was still considered part of the constellation of Argo Navis. After Argo Navis was broken up into Carina, Vela, and Puppis, these Greek-letter designations were kept, so that Puppis does not have a full complement of Greek-letter designations. For example, since Argo Navis's alpha star went to Carina, there is no Alpha Puppis. See also List of stars by constellation References List Puppis	List of stars in Puppis	[ "Astronomy" ]	128	[ "Lists of stars by constellation", "Puppis", "Constellations" ]
8,591,819	https://en.wikipedia.org/wiki/List%20of%20stars%20in%20Pyxis	This is the list of notable stars in the constellation Pyxis, sorted by decreasing brightness. See also Lists of stars by constellation References List Pyxis	List of stars in Pyxis	[ "Astronomy" ]	33	[ "Lists of stars by constellation", "Pyxis", "Constellations" ]
8,591,822	https://en.wikipedia.org/wiki/List%20of%20stars%20in%20Reticulum	This is the list of notable stars in the constellation Reticulum, sorted by decreasing brightness. See also List of stars by constellation References Notes Bibliography List Reticulum	List of stars in Reticulum	[ "Astronomy" ]	35	[ "Lists of stars by constellation", "Reticulum", "Constellations" ]
8,591,828	https://en.wikipedia.org/wiki/List%20of%20stars%20in%20Sagitta	This is the list of notable stars in the constellation Sagitta, sorted by decreasing brightness. See also List of stars by constellation References List Sagitta	List of stars in Sagitta	[ "Astronomy" ]	33	[ "Lists of stars by constellation", "Sagitta", "Constellations" ]
8,591,834	https://en.wikipedia.org/wiki/List%20of%20stars%20in%20Sagittarius	This is the list of notable stars in the constellation Sagittarius, sorted by decreasing brightness. See also List of stars by constellation References List Sagittarius	List of stars in Sagittarius	[ "Astronomy" ]	35	[ "Lists of stars by constellation", "Sagittarius (constellation)", "Constellations" ]
8,591,841	https://en.wikipedia.org/wiki/List%20of%20stars%20in%20Scorpius	This is the list of notable stars in the constellation Scorpius, sorted by decreasing brightness. See also Lists of stars by constellation References List Scorpius	List of stars in Scorpius	[ "Astronomy" ]	35	[ "Lists of stars by constellation", "Scorpius", "Constellations" ]
8,591,843	https://en.wikipedia.org/wiki/List%20of%20stars%20in%20Sculptor	This is the list of notable stars in the constellation Sculptor, sorted by decreasing brightness. See also List of stars by constellation References List Sculptor	List of stars in Sculptor	[ "Astronomy" ]	29	[ "Lists of stars by constellation", "Constellations", "Sculptor (constellation)" ]
8,591,847	https://en.wikipedia.org/wiki/List%20of%20stars%20in%20Scutum	This is the list of notable stars in the constellation Scutum, sorted by decreasing brightness. See also List of stars by constellation References List Scutum	List of stars in Scutum	[ "Astronomy" ]	33	[ "Lists of stars by constellation", "Scutum (constellation)", "Constellations" ]
8,591,853	https://en.wikipedia.org/wiki/List%20of%20stars%20in%20Serpens	This is the list of notable stars in the constellation Serpens, sorted by decreasing brightness. See also List of stars by constellation References List Serpens	List of stars in Serpens	[ "Astronomy" ]	33	[ "Lists of stars by constellation", "Constellations", "Serpens" ]
8,591,859	https://en.wikipedia.org/wiki/List%20of%20stars%20in%20Sextans	This is the list of notable stars in the constellation Sextans, sorted by decreasing brightness. See also List of stars by constellation References List Sextans	List of stars in Sextans	[ "Astronomy" ]	33	[ "Lists of stars by constellation", "Sextans", "Constellations" ]
8,591,867	https://en.wikipedia.org/wiki/List%20of%20stars%20in%20Taurus	This is the list of notable stars in the constellation Taurus, sorted by decreasing brightness. See also List of stars by constellation References List Taurus	List of stars in Taurus	[ "Astronomy" ]	31	[ "Lists of stars by constellation", "Taurus (constellation)", "Constellations" ]
8,591,869	https://en.wikipedia.org/wiki/List%20of%20stars%20in%20Telescopium	This is the list of notable stars in the constellation Telescopium, sorted by decreasing brightness. See also List of stars by constellation References List Telescopium	List of stars in Telescopium	[ "Astronomy" ]	37	[ "Lists of stars by constellation", "Telescopium", "Constellations" ]
8,591,873	https://en.wikipedia.org/wiki/List%20of%20stars%20in%20Triangulum	This is a list of notable stars in the constellation Triangulum, sorted by decreasing brightness. See also List of stars by constellation References List Triangulum	List of stars in Triangulum	[ "Astronomy" ]	33	[ "Lists of stars by constellation", "Triangulum", "Constellations" ]
8,591,877	https://en.wikipedia.org/wiki/List%20of%20stars%20in%20Triangulum%20Australe	This is the list of notable stars in the constellation Triangulum Australe, sorted by decreasing brightness. See also List of stars by constellation References List Triangulum Australe	List of stars in Triangulum Australe	[ "Astronomy" ]	39	[ "Lists of stars by constellation", "Triangulum Australe", "Constellations" ]
8,591,880	https://en.wikipedia.org/wiki/List%20of%20stars%20in%20Tucana	This is the list of notable stars in the constellation Tucana, sorted by decreasing brightness. See also List of stars by constellation Notes References Allen, R. H. (1963). Star Names; Their Lore and Meaning, Dover Publications, Inc., New York, p. 418. Wagman, M. (2003). Lost Stars, The Mcdonald & Woodward Publishing Company, Blacksburg, pp. 306–307. List Tucana	List of stars in Tucana	[ "Astronomy" ]	92	[ "Lists of stars by constellation", "Tucana", "Constellations" ]
8,591,885	https://en.wikipedia.org/wiki/List%20of%20stars%20in%20Ursa%20Major	This is the list of notable stars in the constellation Ursa Major, sorted by decreasing brightness. See also List of stars by constellation References List Ursa Major	List of stars in Ursa Major	[ "Astronomy" ]	33	[ "Lists of stars by constellation", "Ursa Major", "Constellations" ]
8,591,892	https://en.wikipedia.org/wiki/List%20of%20stars%20in%20Ursa%20Minor	This is the list of notable stars in the constellation Ursa Minor, sorted by decreasing brightness. See also List of stars by constellation References List Ursa Minor	List of stars in Ursa Minor	[ "Astronomy" ]	33	[ "Ursa Minor", "Lists of stars by constellation", "Constellations" ]
8,591,895	https://en.wikipedia.org/wiki/List%20of%20stars%20in%20Vela	This is the list of notable stars in the constellation Vela, sorted by decreasing brightness. This constellation's Bayer designations (Greek-letter star names) were given while it was still considered part of the constellation of Argo Navis. After Argo Navis was broken up into Carina, Vela, and Puppis, these Greek-letter designations were kept, so that Vela does not have a full complement of Greek-letter designations. For example, since Argo Navis's alpha star went to Carina, there is no Alpha Velorum. See also List of stars by constellation References List Vela	List of stars in Vela	[ "Astronomy" ]	129	[ "Lists of stars by constellation", "Vela (constellation)", "Constellations" ]
8,591,899	https://en.wikipedia.org/wiki/List%20of%20stars%20in%20Virgo	This is the list of notable stars in the constellation Virgo, sorted by decreasing brightness. See also List of stars by constellation References List Virgo	List of stars in Virgo	[ "Astronomy" ]	31	[ "Lists of stars by constellation", "Virgo (constellation)", "Constellations" ]
8,591,903	https://en.wikipedia.org/wiki/List%20of%20stars%20in%20Volans	This is the list of notable stars in the constellation Volans, sorted by decreasing brightness. See also List of stars by constellation References List Volans	List of stars in Volans	[ "Astronomy" ]	31	[ "Lists of stars by constellation", "Volans", "Constellations" ]
8,592,308	https://en.wikipedia.org/wiki/Comment%20%28computer%20programming%29	In computer programming, a comment is text embedded in source code that a translator (compiler or interpreter) ignores. Generally, a comment is an annotation intended to make the code easier for a programmer to understand often explaining an aspect that is not readily apparent in the program (non-comment) code. For this article, comment refers to the same concept in a programming language, markup language, configuration file and any similar context. Some development tools, other than a source code translator, do parse comments to provide capabilities such as API document generation, static analysis, and version control integration. The syntax of comments varies by programming language yet there are repeating patterns in the syntax among languages as well as similar aspects related to comment content. The flexibility supported by comments allows for a wide degree of content style variability. To promote uniformity, style conventions are commonly part of a programming style guide. But, best practices are disputed and contradictory. Common attributes Support for code comments is defined by each programming language. The features differ by language, but there are several common attributes that apply throughout. Most languages support multi-line block (a.k.a. stream) and/or single line comments. A block comment is delimited with text that marks the start and end of comment text. It can span multiple lines or occupy any part of a line. Some languages allow block comments to be recursively nested inside one another, but others do not. A line comment ends at the end of the text line. In modern languages, a line comment starts with a delimiter but some older languages designate a column at which subsequent text is considered comment. Many languages support both block and line comments using different delimiters for each. For example, C, C++ and their many derivatives support block comments delimited by /* and / and line comments delimited by //. Other languages support only one type of comment. Comments can also be classified as either prologue or inline based on their position and content relative to program code. A prologue comment is a comment (or group of related comments) located near the top of an associated programming topic, such as before a symbol declaration or at the top of a file. An inline comment is a comment that is located on the same line as and to the right of program code to which is refers. Both prologue and inline comments can be represented as either line or block comments. For example: / * prologue block comment; if is about foo() / bool foo() { return true; / inline block comment; if is about this return / } // // prologue line comment; if is about bar() // bool bar() { return false; // inline line comment; if is about this return } Examples of use Describe intent Comments can explain the author's intent why the code is as it is. Some contend that describing what the code does is superfluous. The need to explain the what is a sign that it is too complex and should be re-worked. "Don't document bad code – rewrite it." "Good comments don't repeat the code or explain it. They clarify its intent. Comments should explain, at a higher level of abstraction than the code, what you're trying to do." Highlight unusual practice Comments may explain why a choice was made to write code that is counter to convention or best practice. For example: ' Second variable dim because of server errors produced when reuse form data. ' No documentation available on server behavior issue, so just coding around it. vtx = server.mappath("local settings") The example below explains why an insertion sort was chosen instead of a quicksort, as the former is, in theory, slower than the latter. list = [f (b), f (b), f (c), f (d), f (a), ...]; // Need a stable sort. Besides, the performance really does not matter. insertion_sort (list); Describe algorithm Comments can describe an algorithm as pseudocode. This could be done before writing the code as a first draft. If left in the code, it can simplify code review by allowing comparison of the resulting code with the intended logic. For example: / loop backwards through all elements returned by the server (they should be processed chronologically)/ for (i = (numElementsReturned - 0); i >= 1; i--) { / process each element's data / updatePattern(i, returnedElements[i]); } Sometimes code contains a novel or noteworthy solution that warrants an explanatory comment. Such explanations might be lengthy and include diagrams and formal mathematical proofs. This may describe what the code does rather than intent, but may be useful for maintaining the code. This might apply for highly specialized problem domains or rarely used optimizations, constructs or function-calls. Reference When some aspect of the code is based on information in an external reference, comments link to the reference. For example as a URL or book name and page number. Comment out A common developer practice is to comment out one or more lines of code. The programmer adds comment syntax that converts program code into comments so that what was executable code will no longer be executed at runtime. Sometimes this technique is used to find the cause of a bug. By systematically commenting out and running parts of the program, the offending source code can be located. Many IDEs support adding and removing comments with convenient user interface such as a keyboard shortcut. Store metadata Comments can store metadata about the code. Common metadata includes the name of the original author and subsequent maintainers, dates when first written and modified, link to development and user documentation, and legal information such as copyright and software license. Some programming tools write metadata into the code as comments. For example, a version control tool might write metadata such as author, date and version number into each file when it's committed to the repository. Integrate with development tools Sometimes information stored in comments is used by development tools other than the translator the primary tool that consumes the code. This information may include metadata (often used by a documentation generator) or tool configuration. Some source code editors support configuration via metadata in comments. One particular example is the modeline feature of Vim which configures tab character handling. For example: # vim: tabstop=8 expandtab shiftwidth=4 softtabstop=4 Support documentation generation An API documentation generator parses information from a codebase to generate API documentation. Many support reading information from comments, often parsing metadata, to control the content and formatting of the resulting document. Although some claim that API documentation can be higher quality when written in a more traditional and manual way, some claim that storing documentation information in code comments simplifies the documenting process, as well as increases the likelihood that the documentation will be kept up to date. Examples include Javadoc, Ddoc, Doxygen, Visual Expert and PHPDoc. Forms of docstring are supported by Python, Lisp, Elixir, and Clojure. C#, F# and Visual Basic .NET implement a similar feature called "XML Comments" which are read by IntelliSense from the compiled .NET assembly. Visualization An ASCII art visualization such as a logo, diagram, or flowchart can be included in a comment. The following code fragment depicts the process flow of a system administration script (Windows script file). Although a section marking the code appears as a comment, the diagram is in an XML CDATA section, which is technically not a comment, but serves the same purpose here. Although this diagram could be in a comment, the example illustrates one instance where the programmer opted not to use a comment as a way of including resources in source code. <!-- begin: wsf_resource_nodes --> <resource id="ProcessDiagram000"> <![CDATA[ HostApp (Main_process) \| V script.wsf (app_cmd) --> ClientApp (async_run, batch_process) \| \| V mru.ini (mru_history) ]]> </resource> Store resource data Binary data may also be encoded in comments through a process known as binary-to-text encoding, although such practice is uncommon and typically relegated to external resource files. Document development process Sometimes, comments describe development processes related to the code. For example, comments might describe how to build the code or how to submit changes to the software maintainer. Extend language syntax Occasionally, code that is formatted as a comment is overloaded to convey additional information to the translator, such as conditional comments. As such, syntax that generally indicates a comment can actually represent program code; not comment code. Such syntax may be a practical way to maintain compatibility while adding additional functionality, but some regard such a solution as a kludge. Other examples include interpreter directives: The Unix "shebang" – #! – used on the first line of a script to point to the interpreter to be used. "Magic comments" identifying the encoding a source file is using, e.g. Python's PEP 263. The script below for a Unix-like system shows both of these uses: #!/usr/bin/env python3 # -- coding: UTF-8 -- print("Testing") The gcc compiler (since 2017) looks for a comment in a switch statement if a case falls-thru to the next case. If an explicit indication of fall-thru is not found, then the compiler issues a warning about a possible coding problem. Inserting such a comment about fall-thru is a long standing convention, and the compiler has codified the practice. For example: switch (command) { case CMD_SHOW_HELP_AND_EXIT: do_show_help(); / Fall thru / case CMD_EXIT: do_exit(); break; } Relieve stress To relieve stress or attempt humor, sometimes programmers add comments about the quality of the code, tools, competitors, employers, working conditions, or other arguably unprofessional topics sometimes using profanity. Normative views There are various normative views and long-standing opinions regarding the proper use of comments in source code. Some of these are informal and based on personal preference, while others are published or promulgated as formal guidelines for a particular community. Need for comments Experts have varying viewpoints on whether, and when, comments are appropriate in source code. Some assert that source code should be written with few comments, on the basis that the source code should be self-explanatory or self-documenting. Others suggest code should be extensively commented (it is not uncommon for over 50% of the non-whitespace characters in source code to be contained within comments). In between these views is the assertion that comments are neither beneficial nor harmful by themselves, and what matters is that they are correct and kept in sync with the source code, and omitted if they are superfluous, excessive, difficult to maintain or otherwise unhelpful. Comments are sometimes used to document contracts in the design by contract approach to programming. Level of detail Depending on the intended audience of the code and other considerations, the level of detail and description may vary considerably. For example, the following Java comment would be suitable in an introductory text designed to teach beginning programming: String s = "Wikipedia"; / Assigns the value "Wikipedia" to the variable s. / This level of detail, however, would not be appropriate in the context of production code, or other situations involving experienced developers. Such rudimentary descriptions are inconsistent with the guideline: "Good comments ... clarify intent." Further, for professional coding environments, the level of detail is ordinarily well defined to meet a specific performance requirement defined by business operations. Styles As free-form text, comments can be styled in a wide variety of ways. Many prefer a style that is consistent, non-obstructive, easy to modify, and difficult to break. As some claim that a level of consistency is valuable and worthwhile, a consistent commenting style is sometimes agreed upon before a project starts or emerges as development progresses. The following C fragments show some of diversity in block comment style: / This is the comment body. / /*************************\ * * This is the comment body. * * * \**************************/ Factors such as personal preference, flexibility of programming tools can influence the commenting style used. For example, the first might be preferred by programmers who use a source code editor that does not automatically format a comment as shown in the second example. Software consultant and technology commentator Allen Holub advocates aligning the left edges of comments: / This is the style recommended by Holub for C and C++. * It is demonstrated in ''Enough Rope'', in rule 29. / / This is another way to do it, also in C. It is easier to do in editors that do not automatically indent the second through last lines of the comment one space from the first. ** It is also used in Holub's book, in rule 31. / In many languages, a line comment can follow program code such that the comment is inline and generally describes the code to the left of it. For example, in this Perl: print $s . "\n"; # Add a newline character after printing If a language supports both line and block comments, programming teams may decide upon a convention of when to use which. For example, line comments only for minor comments, and block comments to for higher-level abstractions. Tags Programmers often use one of select words also known as tags, codetags and tokens to categorize the information in a comment. Programmers may leverage these tags by searching for them via a text editor or grep. Some editors highlight comment text based on tags. Commonly used tags include: BUG, DEBUG — identifies a known bug; maybe implying it should be fixed FIXME — implies that there is work to do to fix a bug HACK, BODGE, KLUDGE — marks a solution that might be considered low quality TODO — describes some work to do NOTE — relatively general information UNDONE — a reversal or "roll back" of previous code For example: int foo() { // TODO implement } Examples Syntax for comments varies by programming language. There are common patterns used by multiple languages while also a wide range of syntax among the languages in general. To limit the length of this section, some examples are grouped by languages with the same or very similar syntax. Others are for particular languages that have less common syntax. Curly brace languages Many of the curly brace languages such as C, C++ and their many derivatives delimit a line comment with and a block comment with and . Originally, C lacked the line comment, but it was added in C99. Notable languages include: C, C++, C#, D, Java, JavaScript and Swift. For example: / * Check if over maximum process limit, but be sure to exclude root. * This is needed to make it possible for login to set per-user * process limit to something lower than processes root is running. / bool isOverMaximumProcessLimit() { // TODO implement } Some languages, including D and Swift, allow blocks to be nested while other do not, including C and C++. An example of nested blocks in D: // line comment / block comment / /+ start of outer block /+ inner block +/ end of outer block +/ An example of nested blocks in Swift: / This is the start of the outer comment. /* This is the nested comment. / This is the end of the outer comment. / Scripting A pattern in many scripting languages is to delimit a line comment with #. Support for a block comment varies. Notable languages include: Bash, Raku, Ruby, Perl, PowerShell, Python and R. An example in R: # This is a comment print("This is not a comment") # This is another comment Block in Ruby A block comment is delimited by =begin and =end that start a line. For example: puts "not a comment" # this is a comment puts "not a comment" =begin whatever goes in these lines is just for the human reader =end puts "not a comment" Block in Perl Instead of a regular block commenting construct, Perl uses literate programming plain old documentation (POD) markup. For example: =item Pod::List-E<gt>new() Create a new list object. Properties may be specified through a hash reference like this: my $list = Pod::List->new({ -start => $., -indent => 4 }); =cut sub new { ... } Raku (previously called Perl 6) uses the same line comments and POD comments as Perl, but adds a configurable block comment type: "multi-line / embedded comments". It starts with #` and then an opening bracket character and ends with the matching closing bracket character. For example: #`{{ "commenting out" this version toggle-case(Str:D $s) Toggles the case of each character in a string: my Str $toggled-string = toggle-case("mY NAME IS mICHAEL!"); }} sub toggle-case(Str:D $s) #`( this version of parens is used now ){ ... } Block in PowerShell PowerShell supports a block comment delimited by <# and #>. For example: # Single line comment <# Multi Line Comment #> Block in Python Although Python does not provide for block comments a bare string literal represented by a triple-quoted string is often used for this purpose. In the examples below, the triple double-quoted strings act like comments, but are also treated as docstrings: """ At the top of a file, this is the module docstring """ class MyClass: """Class docstring""" def my_method(self): """Method docstring""" Browser markup Markup languages in general vary in comment syntax, but some of the notable internet markup formats such as HTML and XML delimit a block comment with <!-- and --> and provide no line comment support. An example in XML: <!-- select the context here --> <param name="context" value="public" /> For compatibility with SGML, double-hyphen (--) is not allowed inside comments. ColdFusion provides syntax similar to the HTML comment, but uses three dashes instead of two. CodeFusion allows for nested block comments. Double dash A relatively loose collection of languages use -- for a single line comment. Notable languages include: Ada, Eiffel, Haskell, Lua, SQL and VHDL. Block comment support varies. An example in Ada: -- the air traffic controller task takes requests for takeoff and landing task type Controller (My_Runway: Runway_Access) is -- task entries for synchronous message passing entry Request_Takeoff (ID: in Airplane_ID; Takeoff: out Runway_Access); entry Request_Approach(ID: in Airplane_ID; Approach: out Runway_Access); end Controller; Block in Haskell In Haskell, a block comment is delimited by {- and -}. For example: {- this is a comment on more lines -} -- and this is a comment on one line putStrLn "Wikipedia" -- this is another comment Haskell also provides a literate programming method of commenting known as "Bird Style". Lines starting with > are interpreted as code and everything else is considered a comment. One additional requirement is a blank line before and after the code block: In Bird-style you have to leave a blank before the code. > fact :: Integer -> Integer > fact 0 = 1 > fact (n+1) = (n+1) * fact n And you have to leave a blank line after the code as well. Literate programming can also be accomplished via LaTeX. Example of a definition: \usepackage{verbatim} \newenvironment{code}{\verbatim}{\endverbatim} Used as follows: % the LaTeX source file The \verb\|fact n\| function call computes $n!$ if $n\ge 0$, here is a definition:\\ \begin{code} fact :: Integer -> Integer fact 0 = 1 fact (n+1) = (n+1) * fact n \end{code} Here more explanation using \LaTeX{} markup Block in Lua Lua supports block comments delimited by --[[ and ]] For example: --[[A multi-line long comment ]] Block in SQL In some variants of SQL, the curly brace language block comment (/*/) is supported. Variants include: Transact-SQL, MySQL, SQLite, PostgreSQL, and Oracle. MySQL also supports a line comment delimited by #. Less common syntax APL APL uses ⍝ for a line comment. For example: ⍝ Now add the numbers: c←a+b ⍝ addition In dialects that have the ⊣ ("left") and ⊢ ("right") primitives, comments can often be inside or separate statements, in the form of ignored strings: d←2×c ⊣'where'⊢ c←a+ 'bound'⊢ b AppleScript AppleScript supports both line and block comments. For example: # line comment (in later versions) ( This program displays a greeting. ) on greet(myGreeting) display dialog myGreeting & " world!" end greet -- Show the greeting greet("Hello") BASIC Early versions of BASIC used (short for remark) for a line comment. 10 REM This BASIC program shows the use of the PRINT and GOTO Statements. 15 REM It fills the screen with the phrase "HELLO" 20 PRINT "HELLO" 30 GOTO 20 In later variations, including Quick Basic, Q Basic, Visual Basic (VB), VB.NET, VBScript, FreeBASIC and Gambas, a line comment is delimited with ' (apostrophe). An example in VB.NET: Public Class Form1 Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click ' new style line comment rem old style line comment still supported MessageBox.Show("Hello, World") ' show dialog with a greeting End Sub End Class Cisco IOS and IOS-XE configuration The exclamation point (!) may be used to mark comments in a Cisco router's configuration mode, however such comments are not saved to non-volatile memory (which contains the startup-config), nor are they displayed by the "show run" command. It is possible to insert human-readable content that is actually part of the configuration, and may be saved to the NVRAM startup-config via: The "description" command, used to add a description to the configuration of an interface or of a BGP neighbor The "name" parameter, to add a remark to a static route The "remark" command in access lists ! Paste the text below to reroute traffic manually config t int gi0/2 no shut ip route 0.0.0.0 0.0.0.0 gi0/2 name ISP2 no ip route 0.0.0.0 0.0.0.0 gi0/1 name ISP1 int gi0/1 shut exit Fortran The following Fortran IV code fragment shows that comment syntax is column-oriented. A letter C in the first column causes the entire line to be treated as a comment. C C Lines beginning with 'C' in the first (a.k.a. comment) column are comments C WRITE (6,610) 610 FORMAT(12H HELLO WORLD) END The following Fortran 90 code fragment shows a more modern line comment syntax; text following !. ! A comment program comment_test print '(A)', 'Hello world' ! also a comment end program MATLAB In MATLAB's programming language, the '%' character indicates a single-line comment. Multi line comments are also available via %{ and %} brackets and can be nested, e.g. % These are the derivatives for each term d = [0 -1 0]; %{ %{ (Example of a nested comment, indentation is for cosmetics (and ignored).) %} We form the sequence, following the Taylor formula. Note that we're operating on a vector. %} seq = d . (x - c).^n ./(factorial(n)) % We add-up to get the Taylor approximation approx = sum(seq) Nim Nim delimits a line comment with # and block comments with #[ and ]#. Block comments can be nested. Nim also has documentation comments that use mixed Markdown and ReStructuredText markups. A line documentation comment uses '##' and a block documentation comment uses '##[' and ']##'. The compiler can generate HTML, LaTeX and JSON documentation from the documentation comments. Documentation comments are part of the abstract syntax tree and can be extracted using macros. ## Documentation of the module ReSTructuredText and MarkDown # This is a comment, but it is not a documentation comment. type Kitten = object ## Documentation of type age: int ## Documentation of field proc purr(self: Kitten) = ## Documentation of function echo "Purr Purr" # This is a comment, but it is not a documentation comment. # This is a comment, but it is not a documentation comment. OCaml OCaml supports nestable comments. For exmaple: codeLine(* comment level 1(comment level 2)) Pascal, Delphi In Pascal and Delphi, a block comment is delimited by { and }, and as an alternative for computers that do not support these characters, ( and ) are also supported. A line comment is delimited by \\. In Niklaus Wirth's more modern family of languages (including Modula-2 and Oberon), comments are delimited by ( and ). Comments can be nested. For example: ( test diagonals ) columnDifference := testColumn - column; if (row + columnDifference = testRow) or ....... PHP Comments in PHP can be either curly brace style (both line and block), or line delimited with #l. Blocks cannot be nested. Starting in PHP 8, a # only means comment if it's not immediately followed by [. Otherwise, it delimits an attribute, which continues till the next ]. For example: /* * This class contains a sample documentation. * @author Unknown */ #[Attribute] class MyAttribute { const VALUE = 'value'; // C++ style line comment private $value; # script style line comment public function __construct($value = null) { $this->value = $value; } } Security issues In interpreted languages the comments are viewable to the end user of the program. In some cases, such as sections of code that are "commented out", this may present a security vulnerability. See also Comparison of programming languages (syntax)#Comments Notes and references Further reading Movshovitz-Attias, Dana and Cohen, William W. (2013) Natural Language Models for Predicting Programming Comments. In Association for Computational Linguistics (ACL), 2013. External links How to Write Comments by Denis Krukovsky Source Code Documentation as a Live User Manual by PTLogica How to Write Comments for the Javadoc Tool Source code Articles with example code Articles with example C code Articles with example Java code Articles with example Perl code Metadata	Comment (computer programming)	[ "Technology" ]	6,056	[ "Metadata", "Data" ]
8,592,529	https://en.wikipedia.org/wiki/Akmon	An akmon is a multi-ton concrete block used for breakwater and seawall armouring. It was originally designed in the Netherlands in the 1960s, as an improvement on the tetrapod. References See Also Wave-dissipating concrete block External links Official site (Japanese) Wave-dissipating concrete blocks Dutch inventions	Akmon	[ "Engineering" ]	70	[ "Civil engineering", "Civil engineering stubs" ]
8,593,160	https://en.wikipedia.org/wiki/Forisome	Forisomes are proteins occurring in the sieve tubes of Fabaceae. Their molecules are about 1–3 μm wide and 10–30 μm long. They expand and contract anisotropically in response to changes of electric field, pH, or concentration of Ca2+ ions. Unlike most other moving proteins, the change is not dependent on ATP. Forisomes function as valves in sieve tubes of the phloem system, by reversibly changing shape between low-volume ordered crystalloid spindles and high-volume disordered spherical conformations. The change from ordered to disordered conformation involves tripling of the protein's volume, loss of birefringence present in the crystalline phase, 120% radial expansion and 30% longitudinal shrinkage. In Vicia it was shown that forisomes are associated to the endoplasmic reticulum at sieve plates. There are evidences that the forisomes's behavior could depend on Ca2+ changes provoked by Ca2+-permeable ion channels, located on the endoplasmic reticulum and plasma membrane of sieve elements. responsible for shape changes. Forisomes have possible applications as biomimetic smart materials (e.g. valves in microdevices) or smart composite materials. References External links Forisome: A smart plant protein inside a phloem system Forisome based biomimetic smart materials Forisome Protein, a Key to Biomimetic Materials Motor proteins Smart materials Plant proteins	Forisome	[ "Chemistry", "Materials_science", "Engineering" ]	316	[ "Protein stubs", "Motor proteins", "Materials science", "Biochemistry stubs", "Molecular machines", "Smart materials" ]
8,593,202	https://en.wikipedia.org/wiki/Paulien%20Hogeweg	Paulien Hogeweg (born 1943) is a Dutch theoretical biologist and complex systems researcher studying biological systems as dynamic information processing systems at many interconnected levels. In 1970, together with Ben Hesper, she defined the term bioinformatics as "the study of informatic processes in biotic systems". Early life and education Born in Amsterdam, the Netherlands, Hogeweg graduated with a master's degree from the University of Amsterdam in 1969. In her last year as Biology Masters Student, Hogeweg published her studies on water plants titled Structure of aquatic vegetation: a comparison of aquatic vegetation in India, the Netherlands and Czechoslovakia. While volunteering at Leiden University, Hogeweg started her study as a Ph.D. student at Utrecht University. She published seven articles based on her Ph.D work. She graduated from Utrecht University in 1976. The title of her thesis is "Topics in Biological Pattern Analysis", which addressed pattern formation and pattern recognition in biology. Career After graduating with a Masters in biology she went to volunteer at a Lab at Leiden University. It was when volunteering at Leiden University that she met Hesper and coined the term Bioinformatics, which she defines as:“the study of information processes in biotic systems.” In 1977, Hogeweg opened a research lab dedicated to bioinformatics with Ben Hesper. In 1990, Hogeweg published an important paper in the field of pre-biotic study: Spiral wave structure in pre-biotic evolution hypercycle stable against parasites. In 1991, Hogeweg became a full professor of Theoretical Biology at Utrecht University (UU). Since 2008, Hogeweg has been an Honorary professor at UU. Hogeweg has participated as an editor board member for Journal Theoretical Biology, Bulletin Mathematical Biology, Biosystems, Artificial Life Journal, and Ecological Informatics. Research Starting with asynchronous extensions of L-systems she pioneered agent-based modeling studying development of social structure in animal societies, using the opportunity based "ToDo" principle where agents "do what there is to do", and a "DoDom" principle for dominance ranking, also known as the winner-loser effect. This type of research later became popular in artificial life. When the first biological sequence data became available (from the EMBL) she developed a tree based algorithm for multiple sequence alignment. which is now common practice in sequence alignment and phylogeny. At about the same time she pioneered folding algorithms for predicting RNA secondary structures. RNA folding was also introduced to allow for a non-linear genotype to phenotype mapping to study evolution on complex fitness landscapes . The first phase-phase trajectory of a chaotic attractor in an ecological food-chain model of three differential equations appeared long before chaos became popular. She pioneered the use of cellular automata for studying spatial ecological and evolutionary processes and demonstrated that spatial pattern formation can revert evolutionary selection pressures. Extending the Cellular Potts model (CPM) to study morphogenesis and development she modeled the complete life cycle of Dictyostelium discoideum using simple rules for chemotaxis and differential adhesion . This CPM approach is now used for modeling in various areas of developmental biology, and the migration of immune cells in lymphoid tissues. Finally the CPM is used for EvoDevo research. In recent years, Hogeweg has continued her research on co-evolutionary dynamics and morphogenesis, to expand on “adaptive genomics” and to study the interface between gene regulation and evolution in cellular organisms. Also, her research is focused on evolvability at the level of genome organization and regulatory networks, and has shown RNA increase in complexity as the result of interactions of secondary structure and spatial pattern formation. Collaborations Hogeweg has participated in diverse research groups in biological science. Her contribution varies from developing computational methods such as algorithm for tree based multiple sequence alignment which has become a standard practice. Most importantly, her work has greatly contributed to bioinformatics theory. References External links Official website Theoretical Biology and Bioinformatics Group, Utrecht University 1943 births Living people Dutch women scientists 21st-century Dutch biologists Network scientists Theoretical biologists	Paulien Hogeweg	[ "Biology" ]	855	[ "Bioinformatics", "Theoretical biologists" ]
8,593,762	https://en.wikipedia.org/wiki/300B	In electronics, the 300B is a directly-heated power triode vacuum tube with a four-pin base, introduced in 1938 by Western Electric to amplify telephone signals. It measures high and wide, and the anode can dissipate 40 watts thermal. In the 1980s it began to be used increasingly by audiophiles in home audio equipment. The 300B has good linearity, low noise and good reliability; it is often used in single-ended triode (SET) audio amplifiers of about eight watts output. A push-pull pair can output 20 watts. manufacturers of 300B and other tubes of similar characteristics included EkspoPUL (Electro Harmonix brand), ELROG, Emission Labs - EML, JJ Electronic, KR Audio, TJ FullMusic, Hengyang Electronics (Psvane brand), Linlai, Takatsuki Electric and Western Electric. Prices for new 300B tubes ranged from US$175 to $2,000 per matched pair. Western Electric (tube manufacturer), a small, privately owned company in Rossville, Georgia resumed production of the original 300B in 2018 using the original, 1938 manufacturing standards on a modernized assembly line housed at the Rossville Works. See also List of vacuum tubes References http://www.aes.org/e-lib/browse.cfm?elib=6058 The 300B's history 300B data sheet External links Stereophile: In Search of the Perfect 300B Tube Reviews of 300B tubes. Vacuum tubes	300B	[ "Physics" ]	316	[ "Vacuum tubes", "Vacuum", "Matter" ]
8,594,100	https://en.wikipedia.org/wiki/EXIT%20chart	An extrinsic information transfer chart, commonly called an EXIT chart, is a technique to aid the construction of good iteratively-decoded error-correcting codes (in particular low-density parity-check (LDPC) codes and Turbo codes). EXIT charts were developed by Stephan ten Brink, building on the concept of extrinsic information developed in the Turbo coding community. An EXIT chart includes the response of elements of decoder (for example a convolutional decoder of a Turbo code, the LDPC parity-check nodes or the LDPC variable nodes). The response can either be seen as extrinsic information or a representation of the messages in belief propagation. If there are two components which exchange messages, the behaviour of the decoder can be plotted on a two-dimensional chart. One component is plotted with its input on the horizontal axis and its output on the vertical axis. The other component is plotted with its input on the vertical axis and its output on the horizontal axis. The decoding path followed is found by stepping between the two curves. For a successful decoding, there must be a clear swath between the curves so that iterative decoding can proceed from 0 bits of extrinsic information to 1 bit of extrinsic information. A key assumption is that the messages to and from an element of the decoder can be described by a single number, the extrinsic information. This is true when decoding codes from a binary erasure channel but otherwise the messages are often samples from a Gaussian distribution with the correct extrinsic information. The other key assumption is that the messages are independent (equivalent to an infinite block-size code without local structure between the components) To make an optimal code, the two transfer curves need to lie close to each other. This observation is supported by the theoretical result that for capacity to be reached for a code over a binary-erasure channel there must be no area between the curves and also by the insight that a large number of iterations are required for information to be spread throughout all bits of a code. References T. Richardson and R. Urbanke: "Modern Coding Theory" External links Lecture notes on EXIT charts(PDF) Error detection and correction Information theory	EXIT chart	[ "Mathematics", "Technology", "Engineering" ]	468	[ "Telecommunications engineering", "Reliability engineering", "Applied mathematics", "Error detection and correction", "Computer science", "Information theory" ]
8,594,839	https://en.wikipedia.org/wiki/Comparison%20of%20disk%20encryption%20software	This is a technical feature comparison of different disk encryption software. Background information Operating systems Features Hidden containers: Whether hidden containers (an encrypted container (A) within another encrypted container (B) so the existence of container A can not be established) can be created for deniable encryption. Note that some modes of operation like CBC with a plain IV can be more prone to watermarking attacks than others. Pre-boot authentication: Whether authentication can be required before booting the computer, thus allowing one to encrypt the boot disk. Single sign-on: Whether credentials provided during pre-boot authentication will automatically log the user into the host operating system, thus preventing password fatigue and reducing the need to remember multiple passwords. Custom authentication: Whether custom authentication mechanisms can be implemented with third-party applications. Multiple keys: Whether an encrypted volume can have more than one active key. Passphrase strengthening: Whether key strengthening is used with plain text passwords to frustrate dictionary attacks, usually using PBKDF2 or Argon2. Hardware acceleration: Whether dedicated cryptographic accelerator expansion cards can be taken advantage of. Trusted Platform Module: Whether the implementation can use a TPM cryptoprocessor. Filesystems: What filesystems are supported. Two-factor authentication: Whether optional security tokens (hardware security modules, such as Aladdin eToken and smart cards) are supported (for example using PKCS#11) Layering Whole disk: Whether the whole physical disk or logical volume can be encrypted, including the partition tables and master boot record. Note that this does not imply that the encrypted disk can be used as the boot disk itself; refer to pre-boot authentication in the features comparison table. Partition: Whether individual disk partitions can be encrypted. File: Whether the encrypted container can be stored in a file (usually implemented as encrypted loop devices). Swap space: Whether the swap space (called a "pagefile" on Windows) can be encrypted individually/explicitly. Hibernation file: Whether the hibernation file is encrypted (if hibernation is supported). Modes of operation Different modes of operation supported by the software. Note that an encrypted volume can only use one mode of operation. CBC with predictable IVs: The CBC (cipher block chaining) mode where initialization vectors are statically derived from the sector number and are not secret; this means that IVs are re-used when overwriting a sector and the vectors can easily be guessed by an attacker, leading to watermarking attacks. CBC with secret IVs: The CBC mode where initialization vectors are statically derived from the encryption key and sector number. The IVs are secret, but they are re-used with overwrites. Methods for this include ESSIV and encrypted sector numbers (CGD). CBC with random per-sector keys: The CBC mode where random keys are generated for each sector when it is written to, thus does not exhibit the typical weaknesses of CBC with re-used initialization vectors. The individual sector keys are stored on disk and encrypted with a master key. (See GBDE for details) LRW: The Liskov-Rivest-Wagner tweakable narrow-block mode, a mode of operation specifically designed for disk encryption. Superseded by the more secure XTS mode due to security concerns. XTS: XEX-based Tweaked CodeBook mode (TCB) with CipherText Stealing (CTS), the SISWG (IEEE P1619) standard for disk encryption. Authenticated encryption: Protection against ciphertext modification by an attacker See also Cold boot attack Comparison of encrypted external drives Disk encryption software Disk encryption theory List of cryptographic file systems Notes and references External links DiskCryptor vs Truecrypt – Comparison between DiskCryptor and TrueCrypt Buyer's Guide to Full Disk Encryption – Overview of full-disk encryption, how it works, and how it differs from file-level encryption Disk encryption software Disk encryption software	Comparison of disk encryption software	[ "Mathematics", "Technology" ]	870	[ "Computing-related lists", "Cryptographic software", "Cryptography lists and comparisons", "Mathematical software" ]
8,595,079	https://en.wikipedia.org/wiki/Crossband%20operation	Crossband (cross-band, cross band) operation is a method of telecommunication in which a radio station receives signals on one frequency and simultaneously transmits on another for the purpose of full duplex communication or signal relay. To avoid interference within the equipment at the station, the two frequencies used need to be separated, and ideally on different 'bands'. An unattended station working in this way is a radio repeater. It re-transmits the same information that it receives. This principle is used by telecommunications satellites and terrestrial mobile radio systems. Uses Crossband operation is sometimes used by amateur radio operators. Rather than taking it in turns to transmit on the same frequency, both operators can transmit at the same time but on different bands, each one listening to the frequency that the other is using to transmit. A variation on this procedure includes establishing contact on one frequency and then changing to a pair of other frequencies to exchange messages. Crossband operation is also used in communication between ships (inter-ship) with a HF installation. Frequencies that may be used can be found in the 'Manual for use by the Maritime Mobile and Maritime Mobile-Satellite Services'. Usually inter-ship communication is simplex only (VHF or MF), HF gives the possibility to work duplex but usually the transmitter and receiver are so close to each other that this may cause problems. The solution is to work on frequencies that are far apart e.g.: sending on 8 MHz and receiving on 12 MHz. This mode is often used in amateur radio satellites, with uplink on the VHF band and downlink on UHF band such as IO-86, AO-91, SO-50 and ARISS. Some of satellites such as PO-101 and AO-91 reversed that order with UHF band uplink and VHF band downlink. Such operation required a cross-band directional antenna that can transmit and receive on different antenna. See also See Radio frequency for more details about the radio spectrum. References Further reading Additional articles on crossband repeat usage and setup: www.jpole-antenna.com article Ottawa ARES presentation Santa Clara County ARES/RACES class materials Amateur radio Radio technology	Crossband operation	[ "Technology", "Engineering" ]	439	[ "Information and communications technology", "Telecommunications engineering", "Radio technology" ]
8,595,464	https://en.wikipedia.org/wiki/Cat%20behavior	Cat behavior encompasses the actions and reactions displayed by a cat in response to various stimuli and events. Cat behavior includes body language, elimination habits, aggression, play, communication, hunting, grooming, urine marking, and face rubbing. It varies among individuals, colonies, and breeds. Communication and sociability can vary greatly among individual cats. In a family with many cats, the interactions can change depending on which individuals are present and how restricted the territory and resources are. One or more individuals may become aggressive: fighting may occur with the attack, resulting in scratches and deep bite wounds. Communication Kittens vocalize early in development. Some examples of different vocalizations are described below. Purring - This means that the cat is either content or is self-soothing due to fear. Meowing - A frequently used greeting. A mother meows when interacting with her young. Meows can also be used when a cat wishes for attention. Hissing or spitting - This indicates an angry or defensive cat. Yowling - This means that the cat is in distress or feeling aggressive. Chattering - This occurs when hunting or tracking potential prey. This consists of quick chirps made while the mouth vibrates. The gaze is fixed and staring. This behavior may be in response to a surge of adrenaline or may be caused by the anticipation of a pending hunt. Body language Cats rely strongly on body language to communicate. A cat may rub against an object or lick a person. Much of a cat's body language is through its tail, ears, head position, and back posture. Tail Observing how a cat holds its tail can give a good sense of the cat’s current temperament. Held high, may have a slight curl forward - a sign of friendliness. The cat is happy, content, and comfortable. The tail may quiver or vibrate if the cat is excited. Held low and tucked under - a sign of fear or unease. The cat is attempting to make itself a smaller target to potential threats. Flicking, twitching - a sign of agitation. The cat is on high alert or is upset, and is not receptive to interaction. Cats may also flick their tails in an oscillating, snake-like motion, or abruptly from side to side, often just before pouncing on an object or animal. "Fluffed" or "Halloween-cat tail" - When a cat fluffs up their tails, they are not happy. Here, they are attempting to make themselves appear larger, warning whomever they feel unsafe with, to back off. Eyes When cats greet another cat in their vicinity, they can do a slow, languid, long blink to communicate affection if they trust the person or animal they are in contact with. One way to communicate love and trust to a cat is to say its name, get its attention, look it in the eyes and then slowly blink at it to emulate trust and love. They may return the gesture. In a study of 18 cats, the cat behavior of several half-blinks followed by a prolonged eye narrowing or eye closure was found to be a positive emotional response. They show a specific set of feline behaviors: several half-blinks followed by prolonged eye narrowing or eye closure. When a familiar human slow-blinks towards a cat, the cat tends to approach the human more frequently than if the human has a neutral expression that avoids eye contact. This behavior may share features with the "genuine" human smile that involves the corners of the eyes narrowing. Ears A cat's ears can tell an observer what they are feeling, such as pain, fear, or when they sense danger. At times, one may notice cats tend to have something we call, "airplane ears." This is when their ears are rotated to the sides or angled backward. Cats have acute hearing, so when something scares them, their ears tend to pin to the side or back, and the further they are, the more terrified the cat is. It can be difficult to understand what emotion the cat is portraying with their ears, especially since their ears undergo the same pattern when the cat feels they are in danger/feeling defensive, where their ears pin flat to their heads or turn back. "Airplane" ears do not last that long, only until the moment of danger or fear is over. When cats are in pain or feeling sick, they will hold their ears low, rotated to the side. Cats also show feelings of playfulness and happiness when their ears are pointing forward, straight up. This means the cat is alert and content. Back posture This one is simple--cats make themselves "smaller" when nervous or afraid, but arch their backs when they wish to appear more intimidating when they sense danger and feel defensive. When they arch their backs, they also tend to "fluff" their tails, hence the "Halloween" cat look, known as Piloerection. More information on posture is listed below. Scent rubbing and spraying These behaviors are thought to be a way of marking territory. Facial marking behavior is used to mark their territory as "safe". The cat rubs its cheeks on prominent objects in the preferred territory, depositing a chemical pheromone, known as a contentment pheromone. Synthetic versions of the feline facial pheromone are available commercially. Cats have anal sacs or scent glands. Scent is deposited on the feces as it is eliminated. Unlike intact male cats, female and neutered male cats usually do not spray urine. Spraying is accomplished by backing up against a vertical surface and spraying a jet of urine on that surface. Unlike a dog's penis, a cat's penis points backward. Males neutered in adulthood may still spray after neutering. Urinating on horizontal surfaces in the home outside the litter box may indicate dissatisfaction with the box, due to a variety of factors such as substrate texture, cleanliness and privacy. It can also be a sign of urinary tract problems. Male cats on poor diets are susceptible to crystal formation in the urine, which can block the urethra and create a medical emergency. Body postures A cat's posture communicates its emotions. It is best to observe cats' natural behavior when they are by themselves, with humans, and with other animals. Their postures can be friendly or aggressive, depending on the situation. Some of the most basic and familiar cat postures include: Relaxed posture – The cat is seen lying on the side or sitting. Its breathing is slow to normal, with legs bent, or hind legs laid out or extended. The tail is loosely wrapped, extended, or held up. It also hangs down loosely when the cat is standing. Stretching posture – another posture indicating the cat is relaxed Yawning posture – either by itself or in conjunction with a stretch: another posture of a relaxed cat. Alert posture – The cat is lying on its belly, or it may be sitting. Its back is almost horizontal when standing and moving. Its breathing is normal, with its legs bent or extended (when standing). Its tail is curved back or straight upward, and there may be twitching while the tail is positioned downward. Tense posture – The cat is lying on its belly, with the back of its body lower than its upper body (slinking) when standing or moving back. Its legs, including the hind legs, are bent, and its front legs are extended when standing. Its tail is close to the body, tensed or curled downward. There can be twitching when the cat is standing up. Anxious/ovulating posture – The cat is lying on its belly. The back of the body is visibly lower than the front part when the cat is standing or moving. Its breathing may be fast, and its legs are tucked under its body. The tail is close to the body and may be curled forward (or close to the body when standing), with the tip of the tail moving up and down or side to side. Fearful posture – The cat is lying on its belly or crouching directly on top of its paws. Its entire body may be shaking and very near the ground when standing up. Breathing is fast, with the cat's legs bent near the surface, and its tail is curled and very close to its body when standing on all fours. Confident posture – The cat may walk around in a more comfortable manner with its tail up to the sky, indicating its importance. Cats often walk through houses with their tail standing up high above them, making them look grander and more elegant. Terrified posture – The cat is crouched directly on top of its paws, with visible shaking seen in some parts of the body. Its tail is close to the body, and can be standing up, together with its hair on the back. The legs are very stiff or even bent to increase their size. Typically, cats avoid contact when they feel threatened, although they can resort to varying degrees of aggression when they feel cornered, or when escape is impossible. Grooming Oral grooming for domestic and feral cats is a common behavior; studies on domestic cats show that they spend about 8% of resting time grooming themselves. Grooming is extremely important not only to clean themselves but also to ensure ectoparasite control. Fleas tend to be the most common ectoparasite of cats, and some studies allude to indirect evidence that grooming in cats is effective in removing fleas. Cats do not only use their tongue for grooming to control ectoparasites; scratching may also aid in dislodging fleas from the head and neck. Kneading Kittens "knead" the breast while suckling, using the forelimbs one at a time in an alternating pattern to push against the mammary glands to stimulate lactation in the mother. Cats carry these infantile behaviors beyond nursing and into adulthood. Some cats "nurse," i.e. suck, on clothing or bedding during kneading. The cat exerts firm downward pressure with its paw, opening its toes to expose its claws, then closes its claws as it lifts its paw. The process takes place with alternate paws at intervals of one to two seconds. The cat may knead while sitting on its owner's lap, which may prove painful if the cat has sharp claws. Because most of the preferred "domestic traits" are neotenous, or juvenile traits that persist in the adult, kneading may be a relic juvenile behavior retained in adult domestic cats. It may also stimulate the cat and make it feel good, in the same manner as a human stretching. Kneading is often a precursor to sleeping. Many cats purr while kneading. They also purr mostly when newborn, when feeding, or when trying to feed on their mother's teat. The common association between the two behaviors may corroborate the evidence in favor of the origin of kneading as a remnant instinct. Panting Unlike dogs, panting is a rare occurrence in cats, except in warm weather environments. Cats may pant in response to anxiety, fear or excitement. Panting can also be caused by play, exercise, or stress from things like car rides. However, if panting is excessive or the cat appears in distress, it may be a symptom of a more serious condition, such as a nasal blockage, heartworm disease, head trauma, or drug poisoning. In many cases, feline panting, especially if accompanied by other symptoms, such as coughing or shallow breathing (dyspnea), is considered to be abnormal, and should be treated as a medical emergency. Reflexes Righting reflex The righting reflex is the attempt of cats to land on their feet at the completion of a jump or a fall. They can do this more easily than other animals due to their flexible spine, floating collarbone, and loose skin. Cats also use vision and their vestibular apparatus to help tell which way to turn. They can then stretch themselves out and relax their muscles. The righting reflex does not always result in the cat landing on its feet. Freeze reflex Adult cats are able to make use of pinch-induced behavioural inhibition to induce a "freeze reflex" in their young, which enables them to be transported by the neck without resisting. This reflex, also known as clipnosis, can also be exhibited by adults. Eating patterns Cats are obligate carnivores and do not do well on herbivore diets. In the wild they usually hunt smaller mammals to keep themselves nourished. Many cats find and chew small quantities of long grass, but this is not for its nutritional value per se. The eating of grass seems to stem from feline ancestry and has nothing to do with dietary requirements. It is believed that feline ancestors instead ate grass to purge intestinal parasites. Cats have no sweet taste receptors on their tongue and thus cannot taste sweet things at all. Cats mainly smell for their food, and what they taste for is amino acids instead. This may be a cause of cats being diagnosed with diabetes. The food that domestic cats get has a lot of carbohydrates in it, and a high sugar content cannot be efficiently processed by the digestive system of cats. Cats drink water by lapping the surface with their tongue. A fraction of a teaspoon of water is taken up with each lap. Although some desert cats are able to obtain much of their water needs through the flesh of their prey, most cats come to bodies of water to drink. Eating patterns are another indicator to understand behavior changes in domestic cats. Changes in typical eating patterns can be an early signal for possible physical or psychological health problems. A cat's eating pattern in a domestic setting is essential for the cat and owner bond to form. This happens because cats form attachments to households that regularly feed them. Some cats ask for food dozens of times a day, including at night, with rubbing, pacing, meowing, or sometimes loud purring. Sleeping patterns More than half of cats sleep between 12 and 18 hours a day, sometimes even more. Most cats sleep more as they age. Domestic cats seem to be comparatively flexible with regard to the times of day and night they are active or asleep. Excretion Cats tend to bury their feces after defecating and can be attracted to a litter box if it has attractant in it. Cats will also generally defecate more in those litter boxes. Socialization Socialization is defined as a member of a specific group learning to be part of that group. It is said to be a continuous learning process that allows an individual to learn the necessary skills and behaviors required for a particular social position. Cats, domestic or wild, do participate in social behaviors, even though it is thought that most cat species (besides lions) are solitary, anti-social animals. Under certain circumstances, such as food availability, shelter, or protection, cats can be seen in groups. The social behaviors that cats participate in are colony organization, social learning, socialization between cats, and socialization with humans. Colony organization Free-living domestic cats tend to form colonies. Small colonies consist of one female, known as a queen, and her kittens. Large colonies consist of several queens and their kittens. Male cats are present in both types of colonies and serve the purpose of reproduction and defending territory. Altruistic behavior occurs within these colonies. This means that if an expecting queen helps another queen that just gave birth, then the helping queen will get help in return when she gives birth. Although free living cats are found in colonies, stable social order, like that of the lion, does not exist. Free living cats usually are found in colonies for protection against predators, and for food availability. Although there are many advantages of group living, such as easy access to mates, and defensive measures to protect food, there are also disadvantages, such as sexual competition for mates. If the group gets too big, fights may break out over food. Social learning Cats are observational learners. This type of learning emerges early in a cat's life, and has been shown in many laboratory studies. Young kittens learn to hunt from their mothers by observing their techniques when catching prey. The mother ensures that her kittens learn hunting techniques by first bringing dead prey to the litter, then live prey. She demonstrates the techniques required for successful capture to her kittens by bringing live prey to the litter for the kittens to catch themselves. Prey-catching behavior of kittens improves over time when mothers are present . Observational learning for cats can be described in terms of the drive to complete the behavior, the cue that initiates the behavior, the response to the cue, and the reward for completing the behavior. This is shown when cats learn predatory behavior from their mothers. The drive is hunger, the cue is the prey, the response is to catch the prey, and the reward is to relieve the hunger sensation. Kittens also show observational learning when they are socializing with humans. They are more likely to initiate socialization with humans when their mothers are exhibiting non-aggressive and non-defensive behaviors. Even though mothers spend most time with their kittens, male cats play an important role by breaking up fights among litter mates. Observational learning is not limited to kittens. It can also be observed during adulthood. Studies have been done with adult cats performing a task, such as pressing a lever after a visual cue. Adult cats that see others performing a task learn to perform the same task faster than those who did not witness another cat performing it. Socialization between cats When strange cats meet, they ideally cautiously allow each other to smell their hindquarters, but this does not happen very often. Usually when strange cats meet, one cat makes a sudden movement that puts the other cat into a defensive mode. The subordinate cat will then draw in on itself and prepare to attack if needed. If an attack happens, the subordinate cat will usually run away, but this does not happen all the time and it could lead to a tomcat duel. Dominance is also seen as an underlying factor for how conspecifics -- members of the same species -- interact with each other. Dominance can be seen among cats in multi-cat households. It can be seen when other cats submit to the dominant cat. Dominance includes such behaviors as the subordinate cat walking around the dominant cat, waiting for the dominant cat to walk past, avoiding eye contact, crouching, lying on its side (defensive posture), and retreating when the dominant cat approaches. The dominant cat presents a specific body posture as well. Its ears are straight up, the base of its tail is arched, and it looks directly at the subordinate cat. Dominant cats are usually not aggressive, but if a subordinate cat blocks food they may become aggressive. When this aggressive behavior occurs, it can also lead to the dominant cat preventing subordinate cats from eating and using the litter box. This can cause the subordinate cat to defecate somewhere else and create problems with human interaction. Social conflicts Social conflicts among cats depend solely on the behavior of the cats. Some research has shown that cats rarely pick fights, but when they do, it's usually for protecting food and/or litters, and defending territory. The first sign of an imminent tomcat duel is when both cats draw themselves up high on their legs, all hair along the middle of their backs stands straight up, and they mew and howl loudly as they approach each other. The steps the cats make become slower and shorter the closer they get to each other. Once they are close enough to attack, they pause slightly, and then one cat leaps and tries to bite the nape of the other cat. The other cat has no choice but to retaliate, and both cats roll aggressively on the ground, with loud and intense screams by both. After some time the cats separate and stand face to face to begin the attack all over again. This can go on for some time until one cat does not get up again and remains seated. The defeated cat does not move until the victor has completed a sniff of the area and moves outside the fighting area. Once this happens, the defeated cat leaves the area, ending the duel. Females may also fight with each other, and male-female fights can occur as well. Cats may need to be reintroduced or separated to avoid fights in a closed household. Socialization with humans One way cats and humans interact is through "head bunting," in which a cat rubs its head on a human in order to leave its scent to claim territory and create a bond. Cats can sometimes take cues from human pointing and from the direction of human gazes. They can sometimes discriminate between, and sometimes even correlate, human facial expressions, attentional states, and voices. Besides its own name, a cat can sometimes learn the names of humans and other cats. Cats age three to nine weeks are sensitive to human socialization; after this period socialization can be less effective. Studies have shown that the earlier a kitten is handled, the less fearful it will be toward humans. Other factors that can enhance socialization are having many people handle the kitten frequently, the presence of the mother, and feeding. The presence of the mother is important because cats are observational learners. If the mother is comfortable around humans, it can reduce anxiety in the kitten and promote the kitten-human relationship. Feral kittens around two to seven weeks old can be socialized, usually within a month of capture. Some species of cats cannot be socialized toward humans because of factors such as genetic influence and in some cases specific learning experiences. The best way to get a kitten to socialize is to handle it for many hours a week. The process is made easier if there is another socialized cat present but not necessarily in the same space as the feral cat. If the handler can get a cat to urinate in the litter tray, then the others in a litter will usually follow. Initial contact with thick gloves is highly recommended until trust is established, usually within the first week. Socializing an adult is challenging. Socialized adult feral cats tend to trust only those they trusted in their socialization period, and can be very fearful around strangers. Cats can be companion animals. Studies have shown that these cats provide many physiological and psychological benefits for the owner. Other aspects of cat behavior that are deemed advantageous for the human-cat bond are cat hygiene (cats are known for good hygiene) and they do not have to be taken outside (use of the litter box). Cats are perfect for smaller spaces, and they have no problems with being left alone for extended periods. Even though there are a number of benefits of owning a cat, there are a number of problematic behaviors that can affect the human-cat relationship. One behavior is when cats attack people by clawing and biting. This often occurs spontaneously or is triggered by sudden movements. Another problematic behavior is the "petting and biting syndrome", which involves the cat being petted and then suddenly attacking and running away. Other problems are house soiling, scratching furniture, and when a cat brings dead prey into the house. There are 52 measured personality traits in cats, with one study saying "five reliable personality factors were found using principal axis factor analysis: neuroticism, extroversion, dominance, impulsiveness and agreeableness." Predatory behavior Cats are natural predators. When allowed to roam outdoors, many cats will engage in predation on wildlife, as they are a serious threat to wildlife species. Understanding an indoor cat's personality can go a long way toward satisfying their instincts and avoid potentially inconvenient behavior (such as sudden hissing, dashing around the house, or climbing the curtains). Environmental enrichment items include: A good-sized cat tree, with scratching posts Toys that provide a release for their predatory instincts A well kept litter box or toilet Fresh water and dry cat food Social interaction Attack/Hunting Behavior Although they are natural predators, pet cats tend to only hunt what is most available to them, around where they live. So, if moved to different areas, they can switch between prey depending on their availability. When cats encounter prey, they try to make themselves as quiet and as small as possible, to avoid their prey running from them. Before pouncing at the prey, they push their behinds up into the air and "shake" them with their head low to the ground and paws in front of them so that they can prepare for dismount, or to pounce at their prey. The cat remains extremely tense before springing forward to strike their prey with their paws. When they have difficult access to their prey, such as in small pools of water or holes, they use their paws to "fish" out their food and reach into such areas effectively. When cats finally have control of their food, they tend to cuff or push the prey about, almost playfully. Cats also do something known as "prey shaking" which includes holding their prey in their mouths, and shaking their heads to successfully kill or disorient their prey. If their prey is not dead after this, one or two bites will do. Post Hunting Behavior When their prey is finally dead, they bite them for quite some time, up and down the length of the body. During this time they are picked up and held in their mouths. They chew and pull at their prey using their molars, for grinding. They start at the anterior end of the animal, near its head, enabling them to eat their smaller prey in as fast as one minute. They eat in a crouched position, holding down the victim with their paw(s). Note that while they attack, they do not bite off pieces of the prey until they are dead. Environment Cats like to organize their environment based on their needs. Like their ancestors, domestic cats still have an inherent desire to maintain an independent territory but are generally content to live with other cats for company as they easily get bored. Living alone for a longer time may cause them to forget how to communicate with other cats. Sometimes adding a kitten to a household can be a bad idea. If there already is an older cat present and another cat is added, it may be better to get another older cat that has been socialized with other cats. When a kitten is introduced to a mature cat, that cat may show feline asocial aggression, in which they feel threatened and act aggressive to drive off the intruder. If this happens, the kitten and the cat should be separated and slowly introduced by rubbing towels on the animals and presenting the towel to the other. Cats use scent and pheromones to help organize their territory by marking prominent objects. If these objects or scents are removed, it upsets the cat's perception of its environment. See also Cat behaviorist Cat communication Cat play and toys Ethology Cat training References Animal communication Ethology Articles containing video clips	Cat behavior	[ "Biology" ]	5,482	[ "Behavioural sciences", "Ethology", "Behavior" ]
8,595,634	https://en.wikipedia.org/wiki/Shantanu%20Narayen	Shantanu Narayen (born May 27, 1963) is an Indian-American business executive who has been the chairman, president, and chief executive officer (CEO) of Adobe Inc. since December 2007. Before this, he was the company's president and chief operating officer since 2005. Early life and education Narayen grew up in Hyderabad, India in a Telugu Hindu family. He is the second son of a mother who taught American literature and a father who ran a plastics company. He attended Hyderabad Public School. He earned a bachelor's degree in electronics and communication engineering from University College of Engineering, Osmania University in Hyderabad. He moved to the United States to complete his education, and in 1986 received a master's degree in computer science from Bowling Green State University in Ohio. Later he received an MBA from the Haas School of Business, University of California, Berkeley. Career Early career In 1986 Narayen joined a Silicon Valley start-up called Measurex Automation Systems, which made computer control systems for automotive and electronics customers. He then moved to Apple, where he was in senior management positions from 1989 to 1995. After Apple, he was director of desktop and collaboration products for Silicon Graphics. In 1996 co-founded Pictra Inc., a company that pioneered the concept of digital photo sharing over the Internet. Adobe Narayen joined Adobe in 1998 as senior vice president of worldwide product development, a position he held through 2001. From 2001 to 2005 he was executive vice president of worldwide products. In 2005 he was appointed president and chief operating officer. CEO In November 2007, Adobe announced that Bruce Chizen would step down as CEO effective December 1, 2007, to be replaced by Narayen. As CEO, Narayen led the transformation of the company, moving its creative and digital document software franchises – which include flagship programs such as Photoshop, Premiere Pro, and Acrobat/PDF – from the desktop to the cloud. In addition, during his tenure as CEO, Adobe has entered the digital experiences category, an expansion which began with the company’s acquisition of Omniture in 2009. In 2018 Adobe exceeded $100 billion in market cap and joined the Fortune 500 for the first time. In 2018 it also ranked No. 13 on Forbes’ Most Innovative Companies list. In 2011, Barack Obama appointed him as a member of his Management Advisory Board. Narayen is the lead independent director on the board of directors for Pfizer, and vice chairman of the US-India Strategic Partnership Forum. In 2023, Narayen's total compensation from Adobe was $44.9 million, up 42% from the previous year and representing a CEO-to-median worker pay ratio of 229-to-1. Honors and awards In May 2011, Narayen received an honorary doctorate from his alma mater, Bowling Green State University. In 2018, Narayen was ranked #12 on Fortune'''s "Businessperson of the Year" list, and was deemed "Global Indian of the Year" in 2018 by The Economic Times'' of India. In 2019, he was a recipient of India's Padma Shri award and in 2022 he was the recipient of Armenia's Global High-Tech Award. Personal life Narayen lives in Palo Alto, California. He met his wife Reni while at Bowling Green State University in the mid 1980s; she has a doctorate in clinical psychology. They have two sons. He once represented India in sailing at an Asian Regatta. He, along with Satya Nadella, has also invested in Major League Cricket to be hosted by the American Cricket Enterprises (ACE). References External links Adobe.com: Shantanu Narayen Shantanu Narayen Profile at Forbes Living people Telugu people Businesspeople from Hyderabad, India American technology chief executives Haas School of Business alumni Indian technology chief executives Indian emigrants to the United States Adobe Inc. people Silicon Graphics people Osmania University alumni Bowling Green State University alumni Businesspeople in computing Pfizer people American chief operating officers Recipients of the Padma Shri in trade and industry 20th-century American businesspeople 21st-century American businesspeople American people of Indian descent American computer businesspeople American chief executives American chief executives of Fortune 500 companies Chief executives in the technology industry American people of Telugu descent American computer scientists 1963 births	Shantanu Narayen	[ "Technology" ]	868	[ "Lists of people in STEM fields", "Proprietary technology salespersons" ]
8,595,671	https://en.wikipedia.org/wiki/Navajo%20Lake	Navajo Lake is a reservoir located in San Juan County and Rio Arriba County in northwestern New Mexico, in the southwestern United States. Portions of the reservoir extend into Archuleta County in southern Colorado. The lake is part of the Colorado River Storage Project, which here manages the upper reaches of the San Juan River, storing and releasing water that is used locally for irrigation, or ultimately reaching the Colorado River in Utah. Water is impounded in Navajo Lake by the earth- and rock-filled Navajo Dam, long and high, completed in 1962. The lake is over long and lies at an elevation of up to . The construction of the dam and the resulting lake flooded and destroyed one of the Navajos' most sacred sites. The Lake and associated shoreline areas near the dam in New Mexico and the river shorelines below the dam are part of New Mexico's Navajo Lake State Park, while the Portion of the shoreline and portion of the lake that is located in Colorado make up Navajo State Park which is managed as part of the Colorado State Parks system. The lake has smallmouth bass, black crappie, northern pike, channel catfish, and trout. The waters of Navajo Lake forced hundreds of families to leave their homes and communities. The four communities affected were Los Arboles, Los Pinos, Rose and Los Martinez. The 1.7 million acre-foot reservoir displaced an unknown amount of farms and ranches. It has been estimated that almost 200 families had to move. Some families had been here nearly 80–90 years. See also List of largest reservoirs of Colorado References External links Navajo Lake State Park Buildings and structures in Archuleta County, Colorado Buildings and structures in Rio Arriba County, New Mexico Buildings and structures in San Juan County, New Mexico Bodies of water of Archuleta County, Colorado Bodies of water of San Juan County, New Mexico Colorado River Storage Project Lakes of Rio Arriba County, New Mexico Parks in Archuleta County, Colorado Parks in Rio Arriba County, New Mexico Parks in San Juan County, New Mexico Reservoirs in Colorado Reservoirs in New Mexico State parks of New Mexico 1962 establishments in New Mexico	Navajo Lake	[ "Engineering" ]	434	[ "Colorado River Storage Project" ]
8,596,033	https://en.wikipedia.org/wiki/Moravian%20star	A Moravian star () is an illuminated decoration used during the Christian liturgical seasons of Advent, Christmas, and Epiphany representing the Star of Bethlehem pointing towards the infant Jesus. The Moravian Church teaches: The Moravian star is popular in places where there are Moravian Christian congregations world wide The stars take their English name from the Moravian Church, originating in Moravia. In Germany, they are known as Herrnhut stars, named after the Moravian Mother Community in Saxony, Germany, where they were first commercially produced. With the rise of ecumenism, the use the Moravian star has spread beyond the Moravian Church to other Christian denominations, such as the Lutheran Church and Catholic Church, as well as the Methodist Church. History The first Moravian star is known to have originated in the 1830s at the Moravian Boys' School in Niesky, Germany, as a geometry lesson or project. The first mention is of a 110-point star for the 50th anniversary of the Paedagogium (classical school for boys) in Niesky. Around 1880, Peter Verbeek, an alumnus of the school, began making the stars and their instructions available for sale through his bookstore. His son Harry went on to found the Herrnhut Star Factory, which was the main source of stars until World War I. Although heavily damaged at the end of World War II, the Star Factory resumed manufacturing them. Briefly taken over by the government of East Germany in the 1950s, the factory was returned to the Moravian Church-owned Abraham Dürninger Company, which continues to make the stars in Herrnhut. Other star-making companies and groups have sprung up since then. Some Moravian congregations have congregation members who build and sell the stars as fund raisers. Cultural and Religious importance The star was soon adopted throughout the Moravian Church as an Advent symbol. Moravian stars continue to be displayed during Advent, Christmas, and Epiphany throughout the world, even in areas without a significant Moravian Church presence. Many Moravian households display their stars year-round. The stars are often seen in Moravian nativity and Christmas village displays as a representation of the Star of Bethlehem pointing towards the infant Jesus. They are properly displayed from the first Sunday in Advent (the fourth Sunday before Christmas) until the Festival of Epiphany (January 6). Large advent stars shine in the dome of the Frauenkirche in Dresden and over the altar of the Thomaskirche in Leipzig. A Moravian star, one of the largest in the world, sits atop the North Tower of Atrium Health Wake Forest Baptist during the Advent and Christmas seasons. The city of Winston-Salem, North Carolina, which traces its origins to Salem has Moravian origins dating to 1766, uses the Moravian star as their official Christmas street decoration. Another star sits under Wake Forest University's Wait Chapel during the Advent and Christmas seasons as well. The use of the stars during the Advent, Christmas, and Epiphany seasons is also a tradition in the West Indies, Greenland, Suriname, Labrador, Central America, South and East Africa, Ladakh in India, and in parts of Scandinavia: wherever the Moravian Church has sent missionaries. in 2020, as the world descended in to the Covid19 pandemic, Moravians began to ring, rehang their stars as a sign of love, hope and peace during dark times. On March 27, 2020 Atrium Health Wake Forest Baptist reinstalled their 31 foot star, a top the North Tower. Types of stars The original Moravian star as manufactured in Herrnhut since 1897 exists only in a 26-point form, composed of eighteen square and eight triangular cone-shaped points. The 26th point is missing and used for mounting. This shape is technically known as a Kleetope of a rhombicuboctahedron. Each face of the geometric solid in the middle, the rhombicuboctahedron, serves as the base for one of the pyramid augmentations or starburst points. This is the most commonly seen and most widely available form of Christmas star. Other forms of Christmas star exist, which differ from the original Herrnhut Moravian star. No matter how many points a star has, it has a symmetrical shape based on polyhedra. There are other stars with 20, 32, 50, 62 and 110 points that are commonly hand-made. The variety comes from various ways of forming the polyhedron that provides a base for the points—using an octagonal face instead of a square face, for example. The common original Herrnhut Moravian star becomes a 50-point star when the squares and triangles that normally make up the faces of the polyhedron become octagons and hexagons. This leaves a 4-sided trapezoidal hole in the corners of the faces which is then filled with an irregular four sided point. These 4-sided points form a "starburst" in the midst of an otherwise regular 26-point star. Froebel stars, which are paper decorations made from four folded strips of paper, are sometimes inaccurately also called Moravian stars, among many other names. See also Christingle Illumination (decoration) Lovefeast Nativity scene References External links Make a German Froebel Star Ornament Make a Froebel Star Make a Moravian Star Hardwood Moravian Stars Christmas decorations Christmas in Germany Traditions of the Moravian Church Herrnhut Niesky Advent Star symbols	Moravian star	[ "Mathematics" ]	1,093	[ "Symbols", "Star symbols" ]
8,597,086	https://en.wikipedia.org/wiki/Von%20Neumann%20universal%20constructor	John von Neumann's universal constructor is a self-replicating machine in a cellular automaton (CA) environment. It was designed in the 1940s, without the use of a computer. The fundamental details of the machine were published in von Neumann's book Theory of Self-Reproducing Automata, completed in 1966 by Arthur W. Burks after von Neumann's death. It is regarded as foundational for automata theory, complex systems, and artificial life. Indeed, Nobel Laureate Sydney Brenner considered Von Neumann's work on self-reproducing automata (together with Turing's work on computing machines) central to biological theory as well, allowing us to "discipline our thoughts about machines, both natural and artificial." Von Neumann's goal, as specified in his lectures at the University of Illinois in 1949, was to design a machine whose complexity could grow automatically akin to biological organisms under natural selection. He asked what is the threshold of complexity that must be crossed for machines to be able to evolve. His answer was to specify an abstract machine which, when run, would replicate itself. In his design, the self-replicating machine consists of three parts: a "description" of ('blueprint' or program for) itself, a universal constructor mechanism that can read any description and construct the machine (sans description) encoded in that description, and a universal copy machine that can make copies of any description. After the universal constructor has been used to construct a new machine encoded in the description, the copy machine is used to create a copy of that description, and this copy is passed on to the new machine, resulting in a working replication of the original machine that can keep on reproducing. Some machines will do this backwards, copying the description and then building a machine. Crucially, the self-reproducing machine can evolve by accumulating mutations of the description, not the machine itself, thus gaining the ability to grow in complexity. To define his machine in more detail, von Neumann invented the concept of a cellular automaton. The one he used consists of a two-dimensional grid of cells, each of which can be in one of 29 states at any point in time. At each timestep, each cell updates its state depending on the states of the surrounding cells at the prior timestep. The rules governing these updates are identical for all cells. The universal constructor is a certain pattern of cell states in this cellular automaton. It contains one line of cells that serve as the description (akin to Turing's tape), encoding a sequence of instructions that serve as a 'blueprint' for the machine. The machine reads these instructions one by one and performs the corresponding actions. The instructions direct the machine to use its 'construction arm' (another automaton that functions like an operating system) to build a copy of the machine, without the description tape, at some other location in the cell grid. The description cannot contain instructions to build an equally long description tape, just as a container cannot contain a container of the same size. Therefore, the machine includes the separate copy machine which reads the description tape and passes a copy to the newly constructed machine. The resulting new set of universal constructor and copy machines plus description tape is identical to the old one, and it proceeds to replicate again. Purpose Von Neumann's design has traditionally been understood to be a demonstration of the logical requirements for machine self-replication. However, it is clear that far simpler machines can achieve self-replication. Examples include trivial crystal-like growth, template replication, and Langton's loops. But von Neumann was interested in something more profound: construction, universality, and evolution. Note that the simpler self-replicating CA structures (especially, Byl's loop and the Chou–Reggia loop) cannot exist in a wide variety of forms and thus have very limited evolvability. Other CA structures such as the Evoloop are somewhat evolvable but still don't support open-ended evolution. Commonly, simple replicators do not fully contain the machinery of construction, there being a degree to which the replicator is information copied by its surrounding environment. Although the Von Neumann design is a logical construction, it is in principle a design that could be instantiated as a physical machine. Indeed, this universal constructor can be seen as an abstract simulation of a physical universal assembler. The issue of the environmental contribution to replication is somewhat open, since there are different conceptions of raw material and its availability. Von Neumann's crucial insight is that the description of the machine, which is copied and passed to offspring separately via the universal copier, has a double use; being both an active component of the construction mechanism in reproduction, and being the target of a passive copying process. This part is played by the description (akin to Turing's tape of instructions) in Von Neumann's combination of universal constructor and universal copier. The combination of a universal constructor and copier, plus a tape of instructions conceptualizes and formalizes i) self-replication, and ii) open-ended evolution, or growth of complexity observed in biological organisms. This insight is all the more remarkable because it preceded the discovery of the structure of the DNA molecule by Watson and Crick and how it is separately translated and replicated in the cell—though it followed the Avery–MacLeod–McCarty experiment which identified DNA as the molecular carrier of genetic information in living organisms. The DNA molecule is processed by separate mechanisms that carry out its instructions (translation) and copy (replicate) the DNA for newly constructed cells. The ability to achieve open-ended evolution lies in the fact that, just as in nature, errors (mutations) in the copying of the genetic tape can lead to viable variants of the automaton, which can then evolve via natural selection. As Brenner put it: Evolution of Complexity Von Neumann's goal, as specified in his lectures at the University of Illinois in 1949, was to design a machine whose complexity could grow automatically akin to biological organisms under natural selection. He asked what is the threshold of complexity that must be crossed for machines to be able to evolve and grow in complexity. His “proof-of-principle” designs showed how it is logically possible. By using an architecture that separates a general purpose programmable (“universal”) constructor from a general purpose copier, he showed how the descriptions (tapes) of machines could accumulate mutations in self-replication and thus evolve more complex machines (the image below illustrates this possibility.). This is a very important result, as prior to that, it might have been conjectured that there is a fundamental logical barrier to the existence of such machines; in which case, biological organisms, which do evolve and grow in complexity, could not be “machines”, as conventionally understood. Von Neumann's insight was to think of life as a Turing Machine, which, is similarly defined by a state-determined machine "head" separated from a memory tape. In practice, when we consider the particular automata implementation Von Neumann pursued, we conclude that it does not yield much evolutionary dynamics because the machines are too fragile - the vast majority of perturbations cause them effectively to disintegrate. Thus, it is the conceptual model outlined in his Illinois lectures that is of greater interest today because it shows how a machine can in principle evolve. This insight is all the more remarkable because the model preceded the discovery of the structure of the DNA molecule as discussed above. It is also noteworthy that Von Neumann's design considers that mutations towards greater complexity need to occur in the (descriptions of) subsystems not involved in self-reproduction itself, as conceptualized by the additional automaton D he considered to perform all functions not directly involved in reproduction (see Figure above with Von Neumann's System of Self-Replication Automata with the ability to evolve.) Indeed, in biological organisms only very minor variations of the genetic code have been observed, which matches Von Neumann's rationale that the universal constructor (A) and Copier (B) would not themselves evolve, leaving all evolution (and growth of complexity) to automaton D. In his unfinished work, Von Neumann also briefly considers conflict and interactions between his self-reproducing machines, towards understanding the evolution of ecological and social interactions from his theory of self-reproducing machines. Implementations In automata theory, the concept of a universal constructor is non-trivial because of the existence of Garden of Eden patterns (configurations that have no predecessor). But a simple definition is that a universal constructor is able to construct any finite pattern of non-excited (quiescent) cells. Arthur Burks and others extended the work of von Neumann, giving a much clearer and complete set of details regarding the design and operation of von Neumann's self-replicator. The work of J. W. Thatcher is particularly noteworthy, for he greatly simplified the design. Still, their work did not yield a complete design, cell by cell, of a configuration capable of demonstrating self-replication. Renato Nobili and Umberto Pesavento published the first fully implemented self-reproducing cellular automaton in 1995, nearly fifty years after von Neumann's work. They used a 32-state cellular automaton instead of von Neumann's original 29-state specification, extending it to allow for easier signal-crossing, explicit memory function and a more compact design. They also published an implementation of a general constructor within the original 29-state CA but not one capable of complete replication - the configuration cannot duplicate its tape, nor can it trigger its offspring; the configuration can only construct. In 2004, D. Mange et al. reported an implementation of a self-replicator that is consistent with the designs of von Neumann. In 2007, Nobili published a 32-state implementation that uses run-length encoding to greatly reduce the size of the tape. In 2008, William R. Buckley published two configurations which are self-replicators within the original 29-state CA of von Neumann. Buckley claims that the crossing of signal within von Neumann 29-state cellular automata is not necessary to the construction of self-replicators. Buckley also points out that for the purposes of evolution, each replicator should return to its original configuration after replicating, in order to be capable (in theory) of making more than one copy. As published, the 1995 design of Nobili-Pesavento does not fulfill this requirement but the 2007 design of Nobili does; the same is true of Buckley's configurations. In 2009, Buckley published with Golly a third configuration for von Neumann 29-state cellular automata, which can perform either holistic self-replication, or self-replication by partial construction. This configuration also demonstrates that signal crossing is not necessary to the construction of self-replicators within von Neumann 29-state cellular automata. C. L. Nehaniv in 2002, and also Y. Takada et al. in 2004, proposed a universal constructor directly implemented upon an asynchronous cellular automaton, rather than upon a synchronous cellular automaton. Comparison of implementations As defined by von Neumann, universal construction entails the construction of passive configurations, only. As such, the concept of universal construction constituted nothing more than a literary (or, in this case, mathematical) device. It facilitated other proof, such as that a machine well constructed may engage in self-replication, while universal construction itself was simply assumed over a most minimal case. Universal construction under this standard is trivial. Hence, while all the configurations given here can construct any passive configuration, none can construct the real-time crossing organ devised by Gorman. Practicality and computational cost All the implementations of von Neumann's self-reproducing machine require considerable resources to run on computer. For example, in the Nobili-Pesavento 32-state implementation shown above, while the body of the machine is just 6,329 non-empty cells (within a rectangle of size 97x170), it requires a tape that is 145,315 cells long, and takes 63 billion timesteps to replicate. A simulator running at 1,000 timesteps per second would take over 2 years to make the first copy. In 1995, when the first implementation was published, the authors had not seen their own machine replicate. However, in 2008, the hashlife algorithm was extended to support the 29-state and 32-state rulesets in Golly. On a modern desktop PC, replication now takes only a few minutes, although a significant amount of memory is required. Animation gallery See also Codd's cellular automaton Langton's loops Nobili cellular automata Quine, a program that produces itself as output Santa Claus machine Wireworld References External links John von Neumann's 29 state Cellular Automata Implemented in OpenLaszlo by Don Hopkins Artificial life Cellular automaton patterns Self-replicating machines 3D printing	Von Neumann universal constructor	[ "Physics", "Technology", "Biology" ]	2,690	[ "Physical systems", "Self-replication", "Machines", "Self-replicating machines" ]
15,894,497	https://en.wikipedia.org/wiki/Bing%27s%20recognition%20theorem	In topology, a branch of mathematics, Bing's recognition theorem, named for R. H. Bing, asserts that a necessary and sufficient condition for a M to be homeomorphic to the is that every Jordan curve in M be contained within a topological ball. It is a weak version of the Poincaré conjecture. References 3-manifolds Geometric topology Theorems in topology	Bing's recognition theorem	[ "Mathematics" ]	77	[ "Mathematical theorems", "Theorems in topology", "Geometric topology", "Topology stubs", "Topology", "Mathematical problems" ]
15,894,537	https://en.wikipedia.org/wiki/Aristid%20von%20Grosse	Aristid von Grosse (January 1905 – July 21, 1985) was a German nuclear chemist. During his work with Otto Hahn, he got access to waste material from radium production, and with this starting material he was able in 1927 to isolate protactinium(V) oxide and was later able to produce metallic protactinium by decomposition of protactinium(V) iodide. From 1948 to 1969, he was president of the Research Institute of Temple University and was later affiliated with the laboratories of the Franklin Institute in Philadelphia until his retirement in 1979. In 1971, he received a United States Atomic Energy Commission award in recognition of his "outstanding contributions to the development of nuclear energy." Aristid was born in Riga in January 1905 and moved to the United States in 1930. He retired in 1979 and died of pneumonia in Laguna Hills, California on July 21, 1985. References 1905 births 1985 deaths Scientists from Riga 20th-century American chemists People of Baltic German descent Manhattan Project people Nuclear chemists Temple University faculty Fellows of the American Physical Society Deaths from pneumonia in California Latvian emigrants to the United States	Aristid von Grosse	[ "Chemistry" ]	231	[ "Nuclear chemists" ]
15,895,296	https://en.wikipedia.org/wiki/Equisatisfiability	In mathematical logic (a subtopic within the field of formal logic), two formulae are equisatisfiable if the first formula is satisfiable whenever the second is and vice versa; in other words, either both formulae are satisfiable or both are not. Equisatisfiable formulae may disagree, however, for a particular choice of variables. As a result, equisatisfiability is different from logical equivalence, as two equivalent formulae always have the same models. Whereas within equisatisfiable formulae, only the primitive proposition the formula imposes is valued. Equisatisfiability is generally used in the context of translating formulae, so that one can define a translation to be correct if the original and resulting formulae are equisatisfiable. Examples of translations that preserve equisatisfiability are Skolemization and some translations into conjunctive normal form such as the Tseytin transformation. Examples A translation from propositional logic into propositional logic in which every binary disjunction is replaced by , where is a new variable (one for each replaced disjunction) is a transformation in which satisfiability is preserved: the original and resulting formulae are equisatisfiable. Note that these two formulae are not equivalent: the first formula has the model in which is true while and are false (the model's truth value for being irrelevant to the truth value of the formula), but this is not a model of the second formula, in which has to be true in this case. References Metalogic Model theory Concepts in logic	Equisatisfiability	[ "Mathematics" ]	344	[ "Mathematical logic", "Model theory" ]
15,895,901	https://en.wikipedia.org/wiki/Prescribed%20Ricci%20curvature%20problem	In Riemannian geometry, a branch of mathematics, the prescribed Ricci curvature problem is as follows: given a smooth manifold M and a symmetric 2-tensor h, construct a metric on M whose Ricci curvature tensor equals h. See also Prescribed scalar curvature problem References Thierry Aubin, Some nonlinear problems in Riemannian geometry. Springer Monographs in Mathematics, 1998. Arthur L. Besse. Einstein manifolds. Reprint of the 1987 edition. Classics in Mathematics. Springer-Verlag, Berlin, 2008. xii+516 pp. Dennis M. DeTurck, Existence of metrics with prescribed Ricci curvature: local theory. Invent. Math. 65 (1981/82), no. 1, 179–207. Riemannian geometry Mathematical problems ricci curvature	Prescribed Ricci curvature problem	[ "Physics", "Mathematics" ]	161	[ "Geometric measurement", "Mathematical problems", "Physical quantities", "Curvature (mathematics)" ]
15,896,503	https://en.wikipedia.org/wiki/Southeastern%20Statistical%20Region	The Southeastern Statistical Region () is one of eight statistical regions of North Macedonia. Southeastern, located in the southeastern part of the country, borders Greece and Bulgaria. Internally, it borders the Vardar and Eastern statistical regions. Municipalities The Southeastern statistical region is divided into 10 municipalities: Bogdanci Bosilovo Dojran Gevgelija Konče Novo Selo Radoviš Strumica Valandovo Vasilevo Demographics Population The current population of the Southeastern Statistical Region is 171,416 citizens, according to the last population census in 2002. Ethnicities The largest ethnic group in the region are the Macedonians. References Statistical regions of North Macedonia	Southeastern Statistical Region	[ "Mathematics" ]	134	[ "Statistical regions of North Macedonia", "Statistical concepts", "Statistical regions" ]
15,897,071	https://en.wikipedia.org/wiki/Kappa%20Cephei	Kappa Cephei, Latinized from κ Cephei, is a binary star system in the northern circumpolar constellation of Cepheus. It is visible to the naked eye as a faint, blue white-hued point of light with an apparent visual magnitude is 4.39. The system is located approximately 323–326 light years distant from the Sun, based on parallax. The two gravitationally-bound members of this system had an angular separation of along a position angle of 120°, as of 2015. The primary, designated component A, has a stellar classification of B9III, matching a blue giant. The magnitude 8.34 secondary, component B, is an A-type main-sequence star of class A7V. A third star of 10th magnitude, BD+77 763, is listed as component C in the Washington Double Star Catalog although it is a background object unrelated to the other two. References A-type main-sequence stars B-type giants Binary stars Cepheus (constellation) Cephei, Kappa Durchmusterung objects Cephei, 01 192907 099255 7750	Kappa Cephei	[ "Astronomy" ]	236	[ "Constellations", "Cepheus (constellation)" ]
15,897,104	https://en.wikipedia.org/wiki/Eastern%20Statistical%20Region	The Eastern Statistical Region () is one of eight statistical regions of North Macedonia. Eastern, located in the eastern part of the country, borders Bulgaria. Internally, it borders the Vardar, Skopje, Northeastern, and Southeastern statistical regions. Municipalities Eastern statistical region is divided into 11 municipalities: Demographics Population The current population of the Eastern Statistical Region is 150,234 citizens or 8.2% of the total population of the Republic of North Macedonia, according to the last population census in 2021. Ethnicities The largest ethnic group in the region are the Macedonians. References Statistical regions of North Macedonia	Eastern Statistical Region	[ "Mathematics" ]	119	[ "Statistical regions of North Macedonia", "Statistical concepts", "Statistical regions" ]
15,897,518	https://en.wikipedia.org/wiki/Pi%20Cephei	Pi Cephei (π Cephei) is a trinary star located in the constellation Cepheus. With a combined apparent magnitude of about 4.4, the system is faintly visible to the naked eye. The inner pair of stars orbits in 1.5 years while the outer companion completes one orbit in about 160 years. Pi Cephei was found to have a visual companion star by Otto Wilhelm von Struve in 1843. That the primary is itself a spectroscopic binary was first noticed by William Wallace Campbell in 1901 using photographic plates taken at Lick Observatory. References Spectroscopic binaries Triple star systems Cepheus (constellation) Cephei, Pi Cephei, 33 G-type giants F-type main-sequence stars A-type main-sequence stars 114222 218658 8819 Durchmusterung objects	Pi Cephei	[ "Astronomy" ]	173	[ "Constellations", "Cepheus (constellation)" ]
15,897,912	https://en.wikipedia.org/wiki/T%20Cephei	T Cephei is a Mira variable star in the constellation Cepheus. Located approximately distant, it varies between magnitudes 5.2 and 11.3 over a period of around 388 days. When it is near its maximum brightness, it is faintly visible to the naked eye under good observing conditions. Vitold Ceraski announced his discovery that the star is a variable star, in 1879. It appeared with its variable star designation, T Cephei, in Annie Jump Cannon's 1907 publication Second catalogue of variable stars. T Cephei is a red giant of spectral type M6-9e with an effective temperature 2,400 K, a radius of , a mass of , and a luminosity of . If it were in the place of the Sun, its photosphere would at least engulf the orbit of Mars. This star is believed to be in a late stage of its life, the asymptotic giant branch phase, blowing off its own atmosphere to form a white dwarf in a distant future. See also VV Cephei R Cancri Mira S Cassiopeiae References External links T Cephei in VizieR Cepheus (constellation) Mira variables Cephei, T 202012 M-type giants 8113 104451 Durchmusterung objects Emission-line stars	T Cephei	[ "Astronomy" ]	271	[ "Constellations", "Cepheus (constellation)" ]
15,898,162	https://en.wikipedia.org/wiki/Omicron%20Cephei	Omicron Cephei, Latinized from ο Cephei, is a binary star in the constellation of Cepheus. It consists of a less massive F-type main sequence star in orbit with a more massive G-type giant star. The overall apparent visual magnitude of the system is 4.75. The pair was first determined to be binary by F. G. W. Struve in 1832. Since then, the secondary has been seen to revolve approximately 45 degrees around the primary. A number of orbits have been computed, the most recent giving a period of approximately 1500 years. Visual companion There is a visual companion, CCDM J23186+6807C, to the binary star. It has an approximate apparent visual magnitude of 12.8 and is located approximately 45 arcseconds away from it. References Cepheus (constellation) G-type giants F-type main-sequence stars Triple stars Binary stars Cephei, Omicron Cephei, 34 219916 115088 BD+67 1514 8872	Omicron Cephei	[ "Astronomy" ]	221	[ "Constellations", "Cepheus (constellation)" ]
15,898,570	https://en.wikipedia.org/wiki/19%20Cephei	19 Cephei is a supergiant star in the northern circumpolar constellation of Cepheus. It has a spectral class of O9 and is a member of Cep OB2, an OB association of massive stars located about from the Sun. The spectrum of 19 Cephei shows line profile variability on an hourly and daily timescale. This is thought to be due to the changes in the stellar wind. Double star catalogues list several companions for 19 Cephei. The Washington Double Star Catalog describes four companions: 11th magnitude stars 20" and 56" away, and two 15th magnitude stars 4-5" away. The Catalog of Components of Double and Multiple Stars gives only the two 11th magnitude stars. A scattered cluster of faint stars has been detected associated with 19 Cephei. The brightest likely members apart from 19 Cep itself are 10th magnitude stars. References External links Cepheus (constellation) Cephei, 19 109017 O-type supergiants 209975 08428 BD+61 2246	19 Cephei	[ "Astronomy" ]	213	[ "Constellations", "Cepheus (constellation)" ]
15,898,833	https://en.wikipedia.org/wiki/Wynne%20Edwin%20Baxter	Wynne Edwin Baxter FRMS FGS (1 May 1844 – 1 October 1920) was an English lawyer, translator, antiquarian and botanist, but is best known as the coroner who conducted the inquests on most of the victims of the Whitechapel Murders of 1888 to 1891 including three of the victims of Jack the Ripper in 1888, as well as on Joseph Merrick, the "Elephant Man". Legal career Baxter was the son of William Baxter, youngest of three sons of John Baxter (1781–1858), a Lewes printer and publisher, printer of Baxter's Bible. His Uncle George Baxter was the inventor of a method for colour printing. He attended Lewes Old Grammar School, and was educated privately by the Rev. Frost in Brighton. He studied Law and was admitted as a solicitor in 1867. Maintaining a link with printing, the family business, he was vice-president of the Provincial Newspaper Society between 1871 and 1877. He was appointed Junior Headborough for Lewes in 1868, Under-Sheriff of London and Middlesex from 1876 to 1879 and 1885 to 1886, Junior High Constable in 1878, and the last Senior High Constable in 1880. In 1881 Baxter became the first Mayor of Lewes. He acted as solicitor to Lewes Co-operative Benefit Building Society from 1870 until his death in 1920. He went on to become a member of the Law Society, the Law Association, and the Solicitor's Benevolent Association. Baxter moved from Lewes to London in 1875, starting a solicitor's practice and an advertising agency at the same premises in Cannon Street. He maintained a legal practice at Lewes, which eventually would be run by his son, Reginald 'Reggie' Truscott Baxter. As the Coroner for Sussex from 1880 to 1887, Wynne Baxter conducted the inquest of the Brighton 'railway murderer' Percy Lefroy Mapleton who was hanged in 1881, as well as that of his victim, Isaac Frederick Gold. By 1885 Baxter held two Deputy Coronerships in London, the City of London and Borough of Southwark. In December 1886 he won a bitterly fought contest to be elected the Coroner for the County of Middlesex (Eastern District); he was later appointed Coroner for the County of Middlesex (South Eastern District) from 1889 to 1891, and then for the City of London (Eastern District) and the Liberty of the Tower of London from 1892 until his death. In July 1887 he held the inquest of Miriam Angel, who had been poisoned by Israel Lipski at 16, Batty Street. The name 'Lipski' was to become well known in Whitechapel in the next year, as was that of Baxter himself. Whitechapel Murders Baxter played a key judicial role during the Whitechapel Murders of 1888 to 1891, conducting the inquests into the deaths of Annie Millwood, Emma Elizabeth Smith, Polly Nichols, Annie Chapman, Elizabeth Stride, Rose Mylett, Alice McKenzie, the 'Pinchin Street Torso' and Frances Coles. The inquest for Mary Ann 'Polly' Nichols was conducted by Baxter on 1 September 1888 at the Working Lads' Institute in Whitechapel Road, and was attended by Detective Inspectors Frederick Abberline and Helson and Sergeants Godley and Enright on behalf of the Criminal Investigation Department (CID). Resumed on 3 and 17 September, Baxter heard testimony from numerous witnesses and gave examples of his blunt questioning style, such as this example reported in The Daily Telegraph of 4 September: Baxter, to Henry Tomkins, horse slaughterer: Are there any women about there? Tomkins: Oh! I know nothing about them, I don't like 'em. Baxter: I did not ask you whether you like them; I ask you whether there were any about that night. Baxter's own theory was that the murderer was attempting to obtain certain female organs for sale to doctors along with a medical periodical. Having heard medical evidence from Police Surgeon Dr George Bagster Phillips during the inquest into Annie Chapman's murder, Baxter said: "The body had not been dissected, but the injuries had been made by someone who had considerable anatomical skill and knowledge. There were no meaningless cuts. The organ had been taken by one who knew where to find it, what difficulties he would have to contend against, and how he should use his knife so as to abstract the organ without injury to it....The conclusion that the desire was to possess the missing abdominal organ seemed overwhelming." This theory was disproved soon after Baxter suggested it. Later life Appointed a Life Governor of the London Hospital in 1889, on 15 April 1890 he conducted the inquest into the death of the hospital's most famous resident, Joseph Carey Merrick, the 'Elephant Man', who had died on 11 April 1890. Wynne Edwin Baxter was the last High Constable of Lewes, and became the town's first Mayor in 1881. The painting of Baxter as the first mayor of Lewes (as used at the top of this page), which hangs in the Assembly Room of Lewes Town Hall, is an interesting one. He is shown with the red mayor's gown, the mayoral chain, the mace and the chair. However, these items had to be made and he only had them for the last week of his mayoralty. He was Clerk to the Lewes Provision Market, Governor of the Lewes Exhibition Fund, a member of the Committee of the Lewes National Schools, and a director of the Lewes Victoria Hospital. Between November 1914 and April 1916, during the First World War, Baxter conducted inquests into the deaths of eleven German spies, including Karl Lody, who had been captured in Great Britain and tried and executed at the Tower of London. On 13 June 1917 the Germans launched the first daylight air raid over London. 17 Gotha G biplanes were flown from Belgium, dropping bombs on east London. 162 people were killed and a further 426 were injured during the raid, being the highest death toll from a single air raid on Britain during that war. On 15 June 1917 Baxter presided over the inquests of 20 of the victims at Poplar. Baxter was a noted plant collector, a Fellow of the Geological Society of London and a Fellow and Treasurer of the Royal Microscopical Society. He was fluent in French, and, in the 1890s, translated a number of scientific books from that language into English. Baxter was also an antiquarian, having in his library 3,000 volumes concerning Paradise Lost author John Milton, many of them rare editions. He wrote and delivered academic papers on Milton. He was a member of the archaeological societies of Middlesex, Surrey, Kent, Sussex, and Gloucestershire. In addition, he was Clerk to two City Guilds, the Worshipful Company of Shipwrights and the Worshipful Company of Farriers. Moving to Stoke Newington he served as Chairman of the Public Library Committee, Chairman of the Licensing Bench, and Manager of Barn Street School. He was a prominent Freemason, being a member of the South Saxon Lodge No. 311. In 1907 Baxter said "I have held over 30,000 inquests, and have not had one body exhumed yet". Wynne Edwin Baxter died at his home at 170, Church Street, Stoke Newington, in 1920, at the age of 76. He has a memorial against the east wall of the churchyard of All Saints Church in Lewes. Legacy Baxter's legal practice in Lewes exists today as Mayo Wynne Baxter LLP, which was formed in 2007 with the merger of Mayo & Perkins and Wynne Baxter. The firm has eight offices across Sussex employing about 250 staff. In 2005 the Brighton and Hove Bus Company named their number 657 bus 'Wynne Baxter'. The name on the bus was unveiled during the 'Jack the Ripper' Conference, which that year was held in Brighton. Publications The Domesday Book of Kent – A Return of Owners of Land 1873. By Wynne E Baxter (1877); based on data in the Return of Owners of Land, 1873 government survey. The Domesday Book for the County of Middlesex. By Wynne E. Baxter (Lewes: 1877). The Microscope: Its construction and management. By Dr. Henri Van Heurck, Professor of Botany and Director at the Antwerp Botanical Gardens. Translated by Wynne E. Baxter, FRMS, FGS. London, Crosby, Lockwood & Son, New York, D. Van Nostrand Co., (1893) A Treatise on the Diatomaceae by Henri van Heurck. Translated by Wynne E Baxter. Pub. W. Wesley & Son, London (1896) Media In the 1988 TV mini-series Jack the Ripper, starring Michael Caine as Inspector Abberline, Baxter was played by veteran actor Harry Andrews. References External links Baxter on the Casebook:Jack the Ripper website Baxter as Mayor of Lewes 1844 births 1920 deaths Jack the Ripper English lawyers English solicitors Microscopists People from Lewes Fellows of the Geological Society of London Fellows of the Royal Microscopical Society People educated at Lewes Old Grammar School Freemasons of the United Grand Lodge of England	Wynne Edwin Baxter	[ "Chemistry" ]	1,869	[ "Microscopists", "Microscopy" ]
15,898,836	https://en.wikipedia.org/wiki/16%20Cephei	16 Cephei is a single star located about 119 light years away from the Sun in the constellation of Cepheus. It is visible to the naked eye as a faint, yellow-white hued star with an apparent visual magnitude of 5.036. The star has a relatively high proper motion, traversing the celestial sphere at the rate of 0.174 arc seconds per annum. It is moving closer to the Earth with a heliocentric radial velocity of −21 km/s. This is an ordinary F-type main-sequence star, somewhat hotter than the sun, with a stellar classification of F5 V. It is around two billion years old with a projected rotational velocity of 26.4 km/s. The star has 1.38 times the mass of the Sun and 2.77 times the Sun's radius. It is radiating 11 times the luminosity of the Sun from its photosphere at an effective temperature of 6,238 K. The star is a source of X-ray emission. There are several 11th and 12th magnitude stars within a few arc-minutes of 16 Cephei, all of them distant background objects. Only one of these is listed in the Washington Double Star Catalog and Catalog of Components of Double and Multiple Stars as a companion. References F-type main-sequence stars Double stars Cepheus (constellation) Durchmusterung objects Cephei, 16 108535 209369 8400	16 Cephei	[ "Astronomy" ]	295	[ "Constellations", "Cepheus (constellation)" ]
15,898,987	https://en.wikipedia.org/wiki/Calcium%20channel%2C%20voltage-dependent%2C%20T%20type%2C%20alpha%201H%20subunit	Calcium channel, voltage-dependent, T type, alpha 1H subunit, also known as CACNA1H, is a protein which in humans is encoded by the CACNA1H gene. Function This gene encodes Cav3.2, a T-type member of the α1 subunit family, a protein in the voltage-dependent calcium channel complex. Calcium channels mediate the influx of calcium ions into the cell upon membrane polarization and consist of a complex of α1, α2δ, β, and γ subunits in a 1:1:1:1 ratio. The α1 subunit has 24 transmembrane segments and forms the pore through which ions pass into the cell. There are multiple isoforms of each of the proteins in the complex, either encoded by different genes or the result of alternative splicing of transcripts. Alternate transcriptional splice variants, encoding different isoforms, have been characterized for the gene described here. Clinical significance Studies suggest certain mutations in this gene lead to childhood absence epilepsy (CAE). Variants of Cav3.2 with increased channel activity contribute to susceptibility to idiopathic generalized epilepsy (IGE), but are not sufficient to induce epilepsy on their own. The SFARIgene database lists CACNA1H with an autism score of 2.1, indicating a candidate causal relationship with autism. See also T-type calcium channel References External links Further reading Ion channels Integral membrane proteins	Calcium channel, voltage-dependent, T type, alpha 1H subunit	[ "Chemistry" ]	309	[ "Neurochemistry", "Ion channels" ]
15,899,375	https://en.wikipedia.org/wiki/GTF2A1	Transcription initiation factor IIA subunit 1 is a protein that in humans is encoded by the GTF2A1 gene. Interactions GTF2A1 has been shown to interact with TATA binding protein and TBPL1. See also Transcription Factor II A References Further reading Transcription factors	GTF2A1	[ "Chemistry", "Biology" ]	55	[ "Induced stem cells", "Gene expression", "Transcription factors", "Signal transduction" ]
15,900,022	https://en.wikipedia.org/wiki/A1689-zD1	A1689-zD1 is a galaxy in the Virgo constellation. It was a candidate for the most distant and therefore earliest-observed galaxy discovered , based on a photometric redshift. If the redshift, z~7.6, is correct, it would explain why the galaxy's faint light reaches us at infrared wavelengths. It could only be observed with Hubble Space Telescope's Near Infrared Camera and Multi-Object Spectrometer (NICMOS) and the Spitzer Space Telescope's Infrared Array Camera exploiting the natural phenomenon of gravitational lensing: the galaxy cluster Abell 1689, which lies between Earth and A1689-zD1, at a distance of 2.2 billion light-years from us, functions as a natural "magnifying glass" for the light from the far more distant galaxy which lies directly behind it, at 700 million years after the Big Bang, as seen from Earth. See also IOK-1 UDFy-38135539 List of the most distant astronomical objects References Virgo (constellation) Galaxies Dwarf galaxies Gravitational lensing Astronomical objects discovered in 2008	A1689-zD1	[ "Astronomy" ]	233	[ "Virgo (constellation)", "Constellations" ]
13,212,786	https://en.wikipedia.org/wiki/TerraNet%20AB	Terranet AB is a company that develops technology for Advanced driver-assistance systems (ADAS) and autonomous vehicles. It is headquartered in Sweden and has an office in Stuttgart, Germany. Terranet is currently led by acting CEO Magnus Andersson. Terranet previously focused on delivering mobile telephony and data services via a peer-to-peer mobile mesh network of handsets and light infrastructure. Since 2018, the company is focused on developing technology for advanced driver assistance and autonomous vehicles. Terranet addresses the fast-growing global ADAS market, which is projected to reach USD 84 billion by 2025 - an increase of 150% from 2021. The company's primary focus is to develop and commercialize their BlincVision product, a new type of anti-collision system for advanced driver assistance for motorized vehicles based on laser scanning, event cameras and three-dimensional image analysis. BlincVision is based on Voxelflow, a patented software for advanced three-dimensional image analysis of moving objects. In May 2022, Terranet shared that BlincVision is expected to be production ready in a couple of years. Terranet Holding AB (publ) is listed on Nasdaq First North Premier Growth Market since 2017 (Nasdaq: TERRNT B). History Terranet AB was founded in 2004 by the inventor Anders Carlius, a serial entrepreneur from Lund, Skåne County. Carlius, who came from a background in chip manufacturing with Switchcore and also worked for web portal operator Spray Network, served as the first CEO until 2010. Since its inception Terranet has been headquartered at Lund's Ideon Science Park, which is best known as the home of Ericsson Radio Systems. Carlius says he came up with the idea while travelling on safari in east Africa with his wife Emma. The first extensive pilot project was carried out in the autumn of 2005 on a farming co-operative in Botswana. Other trials included an agreement with Indian operator Bharat Sanchar Nigam to test 50 handsets in late 2012, and a number of pilots in South America. That year, development engineer Conny Do said his main prerogative was to miniaturise Terranet's credit card-sized circuit so that it could be installed in any mobile handset. In 2017, Terranet was listed on Nasdaq First North Premier Growth Market (Nasdaq: TERRNT-B). The following year, the company decided to focus its operations on developing technologies for the automotive industry, more specifically for advanced driver assistance and autonomous vehicles. On October 20, 2020, Terranet signed a Memorandum of Understanding with leading automotive marque Mercedes-Benz AG regarding the use of their advanced driver-assist systems and 3D motion awareness technology. References Mobile radio telephone systems Telecommunications companies of Sweden Mesh networking Companies based in Lund	TerraNet AB	[ "Technology" ]	574	[ "Mobile telecommunications", "Wireless networking", "Mobile radio telephone systems", "Mesh networking" ]
13,213,116	https://en.wikipedia.org/wiki/Captology	Captology is the study of computers as persuasive technologies. This area of inquiry explores the overlapping space between persuasion in general (influence, motivation, behavior change, etc.) and computing technology. This includes the design, research, and program analysis of interactive computing products (such as the Web, desktop software, specialized devices, etc.) created for the purpose of changing people's attitudes or behaviors. B. J. Fogg in 1996 derived the term captology from an acronym: Computers As Persuasive Technologies. In 2003, he published the first book on captology, entitled Persuasive Technology: Using Computers to Change What We Think and Do. Captology is not the same thing as Behavior Design, according to BJ Fogg who is the person who coined both terms and created the foundation for both areas. See also Is Google Making Us Stupid? Humu (software) References Further reading External links The Stanford University Persuasive Technology Lab The Web Credibility Project Persuasive Computers: Perspectives and Research Directions Computing culture 1990s neologisms Persuasion	Captology	[ "Technology" ]	220	[ "Computing culture", "Computer science stubs", "Computer science", "Computing and society", "Computing stubs" ]
13,213,280	https://en.wikipedia.org/wiki/Kachurovskii%27s%20theorem	In mathematics, Kachurovskii's theorem is a theorem relating the convexity of a function on a Banach space to the monotonicity of its Fréchet derivative. Statement of the theorem Let K be a convex subset of a Banach space V and let f : K → R ∪ {+∞} be an extended real-valued function that is Fréchet differentiable with derivative df(x) : V → R at each point x in K. (In fact, df(x) is an element of the continuous dual space V∗.) Then the following are equivalent: f is a convex function; for all x and y in K, df is an (increasing) monotone operator, i.e., for all x and y in K, References (Proposition 7.4) Convex analysis Theorems in functional analysis	Kachurovskii's theorem	[ "Mathematics" ]	179	[ "Theorems in mathematical analysis", "Theorems in functional analysis" ]
13,213,701	https://en.wikipedia.org/wiki/K%C5%8Dmura%27s%20theorem	In mathematics, Kōmura's theorem is a result on the differentiability of absolutely continuous Banach space-valued functions, and is a substantial generalization of Lebesgue's theorem on the differentiability of the indefinite integral, which is that Φ : [0, T] → R given by is differentiable at t for almost every 0 < t < T when φ : [0, T] → R lies in the Lp space L1([0, T]; R). Statement Let (X, \|\| \|\|) be a reflexive Banach space and let φ : [0, T] → X be absolutely continuous. Then φ is (strongly) differentiable almost everywhere, the derivative φ′ lies in the Bochner space L1([0, T]; X), and, for all 0 ≤ t ≤ T, References (Theorem III.1.7) Theorems in measure theory Theorems in functional analysis	Kōmura's theorem	[ "Mathematics" ]	199	[ "Theorems in mathematical analysis", "Theorems in measure theory", "Theorems in functional analysis" ]
13,214,323	https://en.wikipedia.org/wiki/Fixed%20wireless	Fixed wireless is the operation of wireless communication devices or systems used to connect two fixed locations (e.g., building to building or tower to building) with a radio or other wireless link, such as laser bridge. Usually, fixed wireless is part of a wireless LAN infrastructure. The purpose of a fixed wireless link is to enable data communications between the two sites or buildings. Fixed wireless data (FWD) links are often a cost-effective alternative to leasing fiber or installing cables between the buildings. The point-to-point signal transmissions occur through the air over a terrestrial microwave platform rather than through copper or optical fiber; therefore, fixed wireless does not require satellite feeds or local telephone service. The advantages of fixed wireless include the ability to connect with users in remote areas without the need for laying new cables and the capacity for broad bandwidth that is not impeded by fiber or cable capacities. Fixed wireless devices usually derive their electrical power from the public utility mains, unlike mobile wireless or portable wireless devices which tend to be battery powered. Antennas Fixed wireless services typically use a directional radio antenna on each end of the signal (e.g., on each building). These antennas are generally larger than those seen in Wi-Fi setups and are designed for outdoor use. Several types of radio antennas are available that accommodate various weather conditions, signal distances and bandwidths. They are usually selected to make the beam as narrow as possible and thus focus transmit power to their destination, increasing reliability and reducing the chance of eavesdropping or data injection. The links are usually arranged as a point-to-point setup to permit the use of these antennas. This also permits the link to have better speed and or better reach for the same amount of power. These antennas are typically designed to be used in the unlicensed ISM band radio frequency bands (900 MHz, 1.8 GHz, 2.4 GHz and 5 GHz), however, in most commercial installations, licensed frequencies may be used to ensure quality of service (QoS) or to provide higher connection speeds. Fixed wireless broadband Businesses and homes can use fixed-wireless antenna technology to access broadband Internet and Layer 2 networks using fixed wireless broadband. Networks which have redundancy and saturation and antennas that can aggregate signal from multiple carriers are able to offer fail-over and redundancy for connectivity not generally afforded by wired connections. In rural areas where wired infrastructure is not yet available, fixed-wireless broadband can be a viable option for Internet access. See also Internet access Mobile wireless communication Mobile broadband Microwave Bypass Ethernet bridge Wireless ISP References Wireless networking	Fixed wireless	[ "Technology", "Engineering" ]	525	[ "Wireless networking", "Computer networks engineering" ]
13,214,553	https://en.wikipedia.org/wiki/Geographic%20number	A geographic number is a telephone number, from a range of numbers in the United Kingdom National Telephone Numbering Plan, where part of its digit structure contains geographic significance used for routing calls to the physical location of the network termination point of the subscriber to whom the telephone number has been assigned, or where the network termination point does not relate to the geographic area code but where the tariffing remains consistent with that geographic area code. In the Netherlands any telephone number consists of 10 digits and the geographic number is often separated with a minus sign. The number 0592 for example is the geographic number for the area in and around the city Assen, and Groningen uses 050. Someone living in Assen has a caller ID of 6 numbers and someone in Groningen has a caller ID of 7 numbers. See also Telephone number Telephone numbering plan List of country calling codes Caller ID Telephone numbers Identifiers	Geographic number	[ "Mathematics" ]	179	[ "Mathematical objects", "Numbers", "Telephone numbers" ]
13,214,825	https://en.wikipedia.org/wiki/Nigerian%20Society%20of%20Chemical%20Engineers	The Nigerian Society of Chemical Engineers (NSChE) is an organization for chemical engineers in Nigeria. NSChE was officially inaugurated on 12 March 1969 at a meeting at BP House in Lagos attended by twenty four Chemical Engineers, all trained abroad. In 1999 it became a Division of the Nigerian Society of Engineers. The Society publishes the Nigerian Society of Chemical Engineering Journal. Chapters The following Chapters have been granted Charter status by the Council. Anambra/Enugu/Ebonyi States Oyo/Osun States Kaduna/Kastina States Lagos/Ogun States Rivers/Bayelsa States Cross River/Akwa Ibom Imo/Abia States Edo/Delta States Kwara/Kogi States Adamawa/Bauchi/Benue/Yobe/Gombe/Taraba States (ABBYGOT) Benue Industrial FCT/Niger Chapter United States of America (USA) Chapter Student chapters The following student chapters have also been granted Charter Status by the Council: Obafemi Awolowo University, Ile-Ife Chukwuemeka Odumegwu Ojukwu University, uli Ahmadu Bello University, Zaria University of Lagos, Akoka, Lagos University of Port Harcourt, Port Harcourt Rivers State University of Science and Technology, Nkpolu, Port Harcourt; Lagos State University, Ojo; Ladoke Akintola University of Technology, Ogbomoso Enugu State University of science and Technology, Enugu Federal University of Technology, Owerri; Federal University of Technology Yola now known as(Mautech) Kaduna Polytechnic, Kaduna University of Benin, Benin City Petroleum Training Institute, Effurun Auchi Polytechnic, Auchi Michael Okpara University of Agriculture Umudike Abia state Federal University of Petroleum Resources Effurun (FUPRE) References External links NSChE website Chemical engineering organizations Professional associations based in Nigeria Organizations based in Lagos 1969 establishments in Nigeria Organizations established in 1969	Nigerian Society of Chemical Engineers	[ "Chemistry", "Engineering" ]	402	[ "Chemical engineering", "Chemical engineering organizations", "Chemistry organization stubs" ]
13,215,001	https://en.wikipedia.org/wiki/Conveyor%20system	A conveyor system is a common piece of mechanical handling equipment that moves materials from one location to another. Conveyors are especially useful in applications involving the transport of heavy or bulky materials. Conveyor systems allow quick and efficient transport for a wide variety of materials, which make them very popular in the material handling and packaging industries. They also have popular consumer applications, as they are often found in supermarkets and airports, constituting the final leg of item/ bag delivery to customers. Many kinds of conveying systems are available and are used according to the various needs of different industries. There are chain conveyors (floor and overhead) as well. Chain conveyors consist of enclosed tracks, I-Beam, towline, power & free, and hand pushed trolleys. Industries where used Conveyor systems are used widespread across a range of industries due to the numerous benefits they provide. Conveyors are able to safely transport materials from one level to another, which when done by human labor would be strenuous and expensive. They can be installed almost anywhere, and are much safer than using a forklift or other machine to move materials. They can move loads of all shapes, sizes and weights. Also, many have advanced safety features that help prevent accidents. There are a variety of options available for running conveying systems, including the hydraulic, mechanical and fully automated systems, which are equipped to fit individual needs. Conveyor systems are commonly used in many industries, including the Mining, automotive, agricultural, computer, electronic, food processing, aerospace, pharmaceutical, chemical, bottling and canning, print finishing and packaging. Although a wide variety of materials can be conveyed, some of the most common include food items such as beans and nuts, bottles and cans, automotive components, scrap metal, pills and powders, wood and furniture and grain and animal feed. Many factors are important in the accurate selection of a conveyor system. It is important to know how the conveyor system will be used beforehand. Some individual areas that are helpful to consider are the required conveyor operations, such as transport, accumulation and sorting, the material sizes, weights and shapes and where the loading and pickup points need to be. Care and maintenance A conveyor system is often the lifeline to a company's ability to effectively move its product in a timely fashion. The steps that a company can take to ensure that it performs at peak capacity, include regular inspections and system audits, close monitoring of motors and reducers, keeping key parts in stock, and proper training of personnel. Increasing the service life of a conveyor system involves: choosing the right conveyor type, the right system design and paying attention to regular maintenance practices. A conveyor system that is designed properly will last a long time with proper maintenance. Overhead conveyor systems have been used in numerous applications from shop displays, assembly lines to paint finishing plants and more. Impact and wear-resistant materials used in manufacturing Conveyor systems require materials suited to the displacement of heavy loads and the wear-resistance to hold-up over time without seizing due to deformation. Where static control is a factor, special materials designed to either dissipate or conduct electrical charges are used. Examples of conveyor handling materials include UHMW, nylon, Nylatron NSM, HDPE, Tivar, Tivar ESd, and polyurethane. Growth in various industries As far as growth is concerned the material handling and conveyor system makers are getting utmost exposure in the industries like automotive, pharmaceutical, packaging and different production plants. The portable conveyors are likewise growing fast in the construction sector and by the year 2014 the purchase rate for conveyor systems in North America, Europe and Asia is likely to grow even further. The most commonly purchased types of conveyors are line-shaft roller conveyors, chain conveyors and conveyor belts at packaging factories and industrial plants where usually product finishing and monitoring are carried. Commercial and civil sectors are increasingly implementing conveyors at airports, shopping malls, etc. Types Aero-mechanical conveyor Automotive conveyor Belt conveyor Belt-driven live roller conveyor Bucket conveyor Chain conveyor Chain-driven live roller conveyor Drag conveyor Dust-proof conveyor Electric track vehicle system Flexible conveyor Gravity conveyor Gravity skate-wheel conveyor Lineshaft roller conveyor Motorized-drive roller conveyor Overhead I-beam conveyor Overland conveyor Pharmaceutical conveyor Plastic belt conveyor Pneumatic conveyor Screw or auger conveyor Spiral conveyor Tube chain conveyor Tubular Gallery conveyor Vacuum conveyor Vertical conveyor Vibrating conveyor Walking Beam Wire mesh conveyor Pneumatic Every pneumatic system uses pipes or ducts called transport lines that carry a mixture of materials and a stream of air. These materials are free flowing powdery materials like cement and fly ash. Products are moved through tubes by air pressure. Pneumatic conveyors are either carrier systems or dilute-phase systems; carrier systems simply push items from one entry point to one exit point, such as the money-exchanging pneumatic tubes used at a bank drive-through window. Dilute-phase systems use push-pull pressure to guide materials through various entry and exit points. Air compressors or blowers can be used to generate the air flow. Three systems used to generate high-velocity air stream: Suction or vacuum systems, utilizing a vacuum created in the pipeline to draw the material with the surrounding air. The system operated at a low pressure, which is practically 0.4–0.5 atm below atmosphere, and is utilized mainly in conveying light free flowing materials. Pressure-type systems, in which a positive pressure is used to push material from one point to the next. The system is ideal for conveying material from one loading point to a number of unloading points. It operates at a pressure of 6 atm and upwards. Combination systems, in which a suction system is used to convey material from a number of loading points and a pressure system is employed to deliver it to a number of unloading points. Vibrating A vibrating conveyor is a machine with a solid conveying surface which is turned up on the side to form a trough. They are used extensively in food-grade applications to convey dry bulk solids where sanitation, washdown, and low maintenance are essential. Vibrating conveyors are also suitable for harsh, very hot, dirty, or corrosive environments. They can be used to convey newly-cast metal parts which may reach upwards of . Due to the fixed nature of the conveying pans vibrating conveyors can also perform tasks such as sorting, screening, classifying and orienting parts. Vibrating conveyors have been built to convey material at angles exceeding 45° from horizontal using special pan shapes. Flat pans will convey most materials at a 5° incline from horizontal line. Flexible The flexible conveyor is based on a conveyor beam in aluminum or stainless steel, with low-friction slide rails guiding a plastic multi-flexing chain. Products to be conveyed travel directly on the conveyor, or on pallets/carriers. These conveyors can be worked around obstacles and keep production lines flowing. They are made at varying levels and can work in multiple environments. They are used in food packaging, case packing, and pharmaceutical industries and also in large retail stores such as Wal-Mart and Kmart. Spiral Like vertical conveyors, spiral conveyors raise and lower materials to different levels of a facility. In contrast, spiral conveyors are able to transport material loads in a continuous flow. A helical spiral or screw rotates within a sealed tube and the speed makes the product in the conveyor rotate with the screw. The tumbling effect provides a homogeneous mix of particles in the conveyor, which is essential when feeding pre-mixed ingredients and maintaining mixing integrity. Industries that require a higher output of materials - food and beverage, retail case packaging, pharmaceuticals - typically incorporate these conveyors into their systems over standard vertical conveyors due to their ability to facilitate high throughput. Most spiral conveyors also have a lower angle of incline or decline (11 degrees or less) to prevent sliding and tumbling during operation. Vertical Vertical conveyors, also commonly referred to as freight lifts and material lifts, are conveyor systems used to raise or lower materials to different levels of a facility during the handling process. Examples of these conveyors applied in the industrial assembly process include transporting materials to different floors. While similar in look to freight elevators, vertical conveyors are not equipped to transport people, only materials. Vertical lift conveyors contain two adjacent, parallel conveyors for simultaneous upward movement of adjacent surfaces of the parallel conveyors. One of the conveyors normally has spaced apart flights (pans) for transporting bulk food items. The dual conveyors rotate in opposite directions, but are operated from one gear box to ensure equal belt speed. One of the conveyors is pivotally hinged to the other conveyor for swinging the attached conveyor away from the remaining conveyor for access to the facing surfaces of the parallel conveyors. Vertical lift conveyors can be manually or automatically loaded and controlled. Almost all vertical conveyors can be systematically integrated with horizontal conveyors, since both of these conveyor systems work in tandem to create a cohesive material handling assembly line. Like spiral conveyors, vertical conveyors that use forks can transport material loads in a continuous flow. With these forks the load can be taken from one horizontal conveyor and put down on another horizontal conveyor on a different level. By adding more forks, more products can be lifted at the same time. Conventional vertical conveyors must have input and output of material loads moving in the same direction. By using forks many combinations of different input- and output- levels in different directions are possible. A vertical conveyor with forks can even be used as a vertical sorter. Compared to a spiral conveyor a vertical conveyor - with or without forks - takes up less space. Vertical reciprocating conveyors (or VRC) are another type of unit handling system. Typical applications include moving unit loads between floor levels, working with multiple accumulation conveyors, and interfacing overhead conveyors line. Common material to be conveyed includes pallets, sacks, custom fixtures or product racks and more. Motorized Drive Roller (MDR) Motorized Drive Roller (MDR) conveyor utilize drive rollers that have a Brushless DC (BLDC) motor embedded within a conveyor roller tube. A single motorized roller tube is then mechanically linked to a small number of non-powered rollers to create a controllable zone of powered conveyor. A linear collection of these individually powered zones are arranged end to end to form a line of contiguous conveyor. The mechanical performance (torque, speed, efficiency, etc.) of drive rollers equipped with BLDC motors is right in the range of that needed for roller conveyor zones when they need to convey general use carton boxes of the size and weight seen in typical modern warehouse and distribution applications. A typical motorized roller conveyor zone can handle carton items weighing up to approximately 35 kg (75 lbs.). Heavy-duty roller Heavy-duty roller conveyors are used for moving items that weigh at least . This type of conveyor makes the handling of such heavy equipment/products easier and more time effective. Many of the heavy duty roller conveyors can move as fast as . Other types of heavy-duty roller conveyors are gravity roller conveyors, chain-driven live roller conveyors, pallet accumulation conveyors, multi-strand chain conveyors, and chain and roller transfers. Gravity roller conveyors are easy to use and are used in many different types of industries such as automotive and retail. Chain-driven live roller conveyors are used for single or bi-directional material handling. Large, heavy loads are moved by chain driven live roller conveyors. Pallet accumulation conveyors are powered through a mechanical clutch. This is used instead of individually powered and controlled sections of conveyors. Multi-strand chain conveyors are used for double-pitch roller chains. Products that cannot be moved on traditional roller conveyors can be moved by a multi-strand chain conveyor. Chain and roller conveyors are short runs of two or more strands of double-pitch chain conveyors built into a chain-driven line roller conveyor. These pop up under the load and move the load off of the conveyor. Walking Beam It usually consists of two fluid power cylinders or also can use a motor driven cam. For the cylinder driven fluid power type, one axis is for vertical motion and the other for horizontal. Both cam and fluid power types require nests at each station to retain the part that is being moved. The beam is raised, raising the part from its station nest and holding the part in a nest on the walking beam, then moved horizontally, transporting the part to the next nest, then lowered vertically, placing the part in the next station's nest. The beam is then returned to its home position while it is in the lowered position out of the way of the parts. This type of conveying system is useful for parts that need to be accurately physically located or relatively heavy parts. All stations are equidistance and require a nest to retain the part. See also Belt conveyor Chain conveyor Checkweigher Manufacturing Material handling Moving bed heat exchanger Moving walkway Treadmill References M.Marcu-Pipeline Conveyors (theory,photos,state of the art 1990-Pneumatic Pipeline conveyors with wheeled containers) at page 45 in: "Material handling in pyrometallurgy: proceedings of the International Symposium on Materials Handling in Pyrometallurgy, Hamilton, Ontario, August 26–30, 1990-Pergamon press" External links The importance of conveyor and sortation systems for controlled growth (2:03 min. video) Freight transport Packaging machinery Material-handling equipment	Conveyor system	[ "Engineering" ]	2,816	[ "Packaging machinery", "Industrial machinery" ]
13,215,004	https://en.wikipedia.org/wiki/Moreau%27s%20theorem	In mathematics, Moreau's theorem is a result in convex analysis named after French mathematician Jean-Jacques Moreau. It shows that sufficiently well-behaved convex functionals on Hilbert spaces are differentiable and the derivative is well-approximated by the so-called Yosida approximation, which is defined in terms of the resolvent operator. Statement of the theorem Let H be a Hilbert space and let φ : H → R ∪ {+∞} be a proper, convex and lower semi-continuous extended real-valued functional on H. Let A stand for ∂φ, the subderivative of φ; for α > 0 let Jα denote the resolvent: and let Aα denote the Yosida approximation to A: For each α > 0 and x ∈ H, let Then and φα is convex and Fréchet differentiable with derivative dφα = Aα. Also, for each x ∈ H (pointwise), φα(x) converges upwards to φ(x) as α → 0. References (Proposition IV.1.8) Convex analysis Theorems in functional analysis	Moreau's theorem	[ "Mathematics" ]	229	[ "Theorems in mathematical analysis", "Theorems in functional analysis" ]
13,215,186	https://en.wikipedia.org/wiki/Personal%20communications%20network	Personal communications network (PCN) is the European digital cellular mobile telephone network. The underlying standard is known as Digital Cellular System, which defines a variant of GSM operating at 1.7–1.88 GHz. GSM-1800 has since been adopted by other locations, not necessarily under the PCN/DCS name. The network structure, the signal structure and the transmission characteristics are similar between PCN and GSM-900. The PCN system was first initiated by Lord Young, UK Secretary of State for Trade and Industry, in 1988. The main characteristics of PCN are as follows: Operating frequency – 1.7–1.88 GHz (1710–1785 MHz and 1805–1880 MHz). Uses 30 GHz or up for microwave back bone system. Covers both small cells and large cells. Coverage inside and outside buildings. Hand over. Cell delivery. Portable hand set. User intelligent network. The UK government's Department for Enterprise produced 'Phones on the Move: Personal Communications in the 1990s - a discussion document' in January 1989. The document presented a vision for how mobile communications might develop which outlined ideas for both the PCNs and the CT2 standards. PCN is comparable to the North American Personal Communications Service band allocation. The 1800 MHz DCS band is reused in UMTS, LTE and 5G NR; it sees real-world deployment in LTE as "band 3". External links Press Notice: LORD YOUNG CALLS FOR APPLICATIONS TO RUN "PHONES ON THE MOVE" Telephony Wireless networking	Personal communications network	[ "Technology", "Engineering" ]	311	[ "Wireless networking", "Computer networks engineering" ]
13,215,593	https://en.wikipedia.org/wiki/Lp0%20on%20fire	lp0 on fire (also known as Printer on Fire) is an outdated error message generated on some Unix and Unix-like computer operating systems in response to certain types of printer errors. lp0 is the Unix device handle for the first line printer, but the error can be displayed for any printer attached to a Unix or Linux system. It indicates a printer error that requires further investigation to diagnose, but not necessarily that it is on fire. Printer flammability In the late 1950s, high speed computerized printing was still a somewhat experimental field. The first documented fire-starting printer was a Stromberg-Carlson 5000 xerographic printer (similar to a modern laser printer, but with a CRT as the light source instead of a laser), installed around 1959 at the Lawrence Livermore National Laboratory and modified with an extended fusing oven to achieve a print speed of one page per second. In the event of a printing stall, and occasionally during normal operation, the fusing oven would cause the paper to combust. This fire risk was aggravated by the fact that if the printer continued to operate, it would feed a fire with fresh paper at high speed. However, there is no evidence of the "lp0 on fire" message appearing in any software of the time. As the technology matured, most large printer installations were drum printers, a type of impact printer which could print an entire line of text at once through the use of a high speed rotary printing drum. It was thought that in the event of a severe jam, the friction of paper against the drum could ignite either the paper itself, or, in a dirty machine, the accumulated paper and ink dust in the mechanism. Whether this ever happened is not known; there are no reports of friction-related printer fires. The line printer employed a series of status codes, specifically ready, online, and check. If the online status was set to "off" and the check status was set to "on," the operating system would interpret this as the printer running out of paper. However, if the online code was set to "on" and the check code was also set to "on", it meant that the printer still had paper, but was suffering an error (and may still be attempting to run). Due to the potentially hazardous conditions which could arise in early line printers, UNIX displayed the message "on fire" to motivate any system operator viewing the message to go and check on the line printer immediately. In the early 1980s, Xerox created a prototype laser printer engine and provided units to various computer companies. To fuse the toner, the paper path passed a glowing wire. If paper jammed anywhere in the path, the sheet in the fuser caught fire. The prototype UNIX driver reported paper jams as "on fire." Later print engine models used a hot drum in place of the wire. Phrase origins Michael K. Johnson ("mkj" of Red Hat and Fedora fame) wrote the first Linux version of this error message in 1992. However, he, Herbert Rosmanith and Alan Cox (all Linux developers) have acknowledged that the phrase existed in Unix in different forms prior to his Linux printer implementation. Since then, the lp printer code has spread across all sorts of POSIX-compliant operating systems, which often still retain this legacy message. Modern printer drivers and support have improved and hidden low-level error messages from users, so most Unix/Linux users today have never seen the "on fire" message. The "on fire" message remains in the Linux source code as of version 6.0. The message is also present in other software modules, often to humorous effect. For example, in some kernels' CPU code, a CPU thermal failure could result in the message "CPU#0: Possible thermal failure (CPU on fire ?)" and similar humor can be found in the phrase "halt and catch fire". See also HTTP 418 Not a typewriter PC LOAD LETTER References Computer errors Computer humour Computer printers Fire	Lp0 on fire	[ "Chemistry", "Technology" ]	822	[ "Computer errors", "Combustion", "Fire" ]
13,215,976	https://en.wikipedia.org/wiki/Plug-%26-Play%20TV%20Games	Plug-&-Play TV Games is a series of plug-n-play game devices produced by Jakks Pacific. When connected to a television set via RCA connector cables, the user is able to play a pre-defined selection of video games. Some models are collections of ports of games by companies such as Atari and Namco, while others are collections of original games. Some versions facilitate the addition of games, via proprietary GameKey expansion cards, and/or include wireless features. List of games 1 vs 100 Activision Are You Smarter Than A 5th Grader? Atari series Atari Joystick Controller TV Video Game System Atari Paddle Controller TV Game System Avatar: The Last Airbender The Batman Bejeweled Deluxe Big Buck Hunter Pro Big Buck Safari Blue's Room Capcom Cars 2 Deal or No Deal Disney series Disney Princess Dora the Explorer series Dragon Ball Z DreamWorks Animation EA Sports Madden, NHL 95 & FIFA '96 Elmo's World Fantastic Four Frogger Go, Diego, Go! Hannah Montana High School Musical Jeopardy! Max Force Mortal Kombat ¡Mucha Lucha! My Little Pony Pac-Man and Ms. Pac-Man series (Namco series) PAW Patrol series Nicktoons series Pixar Power Rangers series The Price Is Right Phineas and Ferb Retro Arcade featuring Space Invaders Scooby-Doo Sesame Street Shrek Spider-Man series (Notable games include: The Amazing Spider-Man and the Masked Menace, Spider-Man's Villain Roundup, more) SpongeBob SquarePants series (Notable games include: The Fry-Cook Games, Jellyfish Dodge, more) Star Wars series Superman Super Silly Makeover Tele-Doodle Thomas & Friends series (Games include: Right on Time and Learning Circus Express) Triple Header Sports Toy Story series Ultimotion series (Unlicensed Wii Clones) The Walking Dead Zombie Hunter Wall-E Winnie the Pooh Winx Club Wheel of Fortune series WWE World Poker Tour C64 Direct to TV Your Windows XPLaptop References Video game platforms [ The person editing this and has done plenty of research from multiple trustworthy sources. ]	Plug-&-Play TV Games	[ "Technology" ]	432	[ "Computing platforms", "Video game platforms" ]
13,217,890	https://en.wikipedia.org/wiki/IMO%20number	The IMO number of the International Maritime Organization is a generic term covering two distinct meanings. The IMO ship identification number is a unique ship identifier; the IMO company and registered owner identification number is used to identify uniquely each company and/or registered owner managing ships of at least 100 gross tons (gt). The schemes are managed in parallel, but IMO company/owner numbers may also be obtained by managers of vessels not having IMO ship numbers. IMO numbers were introduced to improve maritime safety and reduce fraud and pollution, under the International Convention for the Safety of Life at Sea (SOLAS). The IMO ship number scheme has been mandatory, for SOLAS signatories, for passenger and cargo ships above a certain size since 1996, and voluntarily applicable to various other vessels since 2013/2017. The number identifies a ship and does not change when the ship's owner, country of registry (flag state) or name changes, unlike the official numbers used in some countries, e.g. the UK. The ship's certificates must also bear the IMO ship number. Since 1 July 2004, passenger ships are also required to carry the marking on a horizontal surface visible from the air. History IMO resolutions (1987–2017) In 1987 the IMO adopted Resolution A.600(15) to create the IMO ship identification number scheme aimed at the "enhancement of maritime safety and pollution prevention and the prevention of maritime fraud" by assigning to each ship a unique permanent identification number. Lloyd's Register had already introduced permanent numbers for all the ships in their published register in 1963, and these were modified to seven-digit numbers in 1969. It is this number series that was adopted as the basis for IMO ship numbers in 1987. Unique and permanent numbers are needed due to the frequent changes in ships' names or other details. As one example, the vessel with IMO ship number "IMO 9176187" was built in Japan, has been through the names Asia Melody, Cornelie Oldendorff, Maxima, Jaydee M, Evangelia, Evangeli, Shinsung Dream and Orange Dream, has operated under the flags of Panama, Liberia, Marshall Islands, the Republic of Korea and Sierra Leone, with numerous different owners/operators, and has had home ports of Majuro, Freetown and Cheju, but its IMO number has remained unchanged throughout. The original resolution applied to cargo vessels (meaning "ships which are not passenger ships") at least 300 gt and passenger vessels of at least 100 gt. This resolution was revoked in 2013, being replaced by Resolution A.1078(28), which allowed application of the Scheme to ships of 100 gt and above, including fishing vessels. That in turn was revoked in 2017 and replaced by Resolution A.1117(30), which allows its application to ships of 100 gt and above, "including fishing vessels of steel and non-steel hull construction; passenger ships of less than 100 gt, high-speed passenger craft and mobile offshore drilling units [...]; and all motorized inboard fishing vessels of less than 100 gt down to a size limit of 12 metres in length overall (LOA), authorized to operate outside waters under the national jurisdiction of the flag State". IMO resolutions are "for implementation on a voluntary basis". Although not mandatory under SOLAS, since IMO ship numbers became available also to fishing vessels in 2013, some regional fisheries management organisations, the European Union and other organizations or states have made them mandatory for fishing vessels above a certain size. SOLAS regulation (1994) SOLAS regulation XI-1/3 was adopted in 1994 and came into force on 1 January 1996, making IMO ship numbers mandatory for those countries that have ratified (or acceded to, accepted, approved, adopted, etc.) SOLAS. The IMO scheme and hence SOLAS regulation does not apply to: ships without mechanical means of propulsion pleasure yachts ships engaged on special service (e.g. lightships, SAR vessels) hopper barges hydrofoils, air cushion vehicles floating docks and structures classified in a similar manner ships of war and troopships wooden ships. Security enhancements 2002 In December 2002, the Diplomatic Conference on Maritime Security adopted a number of measures aimed at enhancing security of ships and port facilities. This included a modification to SOLAS Regulation XI-1/3 to require the IMO ship numbers to be permanently marked in a visible place either on the ship's hull or superstructure as well as internally and on the ship's certificates. Passenger ships should also carry the marking on a horizontal surface visible from the air. The enhanced regulations came into effect on 1 July 2004. Company and Registered Owner Regulation 2005 In May 2005, IMO adopted a new SOLAS regulation XI-1/3-1 on the mandatory company and registered owner identification number scheme, with entry into force on 1 January 2009. The regulation provides that every ship owner and management company shall have a unique identification number. Other amendments require these numbers to be added to the relevant certificates and documents in the International Safety Management Code (ISM) and the International Ship and Port Facility Security Code (ISPS). Like the IMO ship identification number, the company identification number is a seven-digit number with the prefix IMO. For example, for the ship Atlantic Star (IMO 8024026), IMO 5304986 referred to the former ship manager Pullmantur Cruises Ship Management Ltd and IMO 5364264 to her former owner, Pullmantur Cruises Empress Ltd. Assignment S&P Global is the manager of the scheme and, as such, identifies and assigns IMO numbers without charge. The organization was previously known as Lloyd's Register-Fairplay, IHS Fairplay and IHS Maritime. For new vessels, the IMO ship number is assigned to a hull during construction, generally upon keel laying. Many vessels which fall outside the mandatory requirements of SOLAS have numbers allocated by Lloyd's Register or IHS Markit in the same numerical series, including fishing vessels and commercial yachts. Structure IMO number of a vessel An IMO number is made of the three letters "IMO" followed by a seven-digit number. This consists of a six-digit sequential unique number followed by a check digit. The integrity of an IMO number can be verified using its check digit. The checksum of an IMO ship identification number is calculated by multiplying each of the first six digits by a factor of 7 to 2 corresponding to their position from right to left. The rightmost digit of this sum is the check digit. Example for IMO 9074729: (9×7) + (0×6) + (7×5) + (4×4) + (7×3) + (2×2) = 139. IMO number of a company The checksum of an IMO company and registered owner identification number is calculated somewhat differently. The first six digits are multiplied by the respective weights: 8, 6, 4, 2, 9, and 7 and then summed. From this sum modulo 11 is taken. The result of which is subtracted from 11. And modulo 10 of this difference results in the check digit. Example for company IMO 2041999: See also ENI number, a comparable system for European barges and other inland waterway vessels Maritime Mobile Service Identity (MMSI), 9-digit numbers identifying mobile radio stations, used alongside IMO numbers References External links IMO Identification Numbers for Ships, Companies & Registered Owners by IHS Markit IMO NUMBER SEARCH International Maritime Organization Law of the sea Ship identification numbers Ship registration	IMO number	[ "Mathematics" ]	1,574	[ "Ship identification numbers", "Mathematical objects", "Numbers" ]
13,217,926	https://en.wikipedia.org/wiki/Tikker	A tikker, alternately spelled ticker, was a vibrating interrupter used in early wireless telegraphy radio receivers such as crystal radio receivers in order to receive continuous wave (CW) radiotelegraphy signals. In the early years of the 20th century, before modern AM or FM radio transmission was developed, radio transmitters communicated information by radiotelegraphy; the transmitter was switched off and on by the operator with a telegraph key, producing pulses of radio waves, to spell out text messages in Morse code. Around 1905 the first continuous wave radio transmitters began to replace the earlier spark transmitters. The Morse code signal of the spark transmitter consisted of pulses of radio waves called damped waves which repeated at an audio rate, so they were audible as a buzz or tone in a receiver's earphones. In contrast the new continuous wave transmitters produced a signal consisting of pulses of continuous waves, unmodulated sinusoidal carrier waves, which were inaudible in the earphones. So to receive this new modulation method, the receiver had to produce a tone during the pulses of carrier. The "tikker", invented in 1908 by Valdemar Poulsen, was the first primitive device that did this. It consisted of a vibrating switch contact between the receiver's detector and earphone, which was repeatedly opened by an electromagnet. It functioned as a crude modulator; it interrupted the signal from the detector at an audio rate, producing a buzz in the earphone whenever the carrier was present. Thus the "dots" and "dashes" of the Morse code were made audible. Around 1915 the tikker was replaced by a better means of accomplishing the same thing; the heterodyne receiver invented by Reginald Fessenden in 1902. In this an electronic oscillator generated a radio signal at a frequency fo offset from the incoming radio wave carrier fC. This was applied to the rectifying detector with the radio carrier. In the detector the two signals mixed, creating a heterodyne (beat) signal at the difference fC - fC between these frequencies, which was in the audio frequency range. The heterodyne provided the audible tone in the earphone whenever the carrier was present. After vacuum tube oscillators were invented in 1913 by Alexander Meissner the heterodyne receiver replaced the tikker. Today the heterodyne method is still used to receive CW signals, and the beat frequency oscillator (BFO) is a standard part of all communications receivers. References Radio technology	Tikker	[ "Technology", "Engineering" ]	518	[ "Information and communications technology", "Telecommunications engineering", "Radio technology" ]
13,218,926	https://en.wikipedia.org/wiki/Standard%20Commands%20for%20Programmable%20Instruments	The Standard Commands for Programmable Instruments (SCPI; often pronounced "skippy") defines a standard for syntax and commands to use in controlling programmable test and measurement devices, such as automatic test equipment and electronic test equipment. Overview SCPI was defined as an additional layer on top of the specification "Standard Codes, Formats, Protocols, and Common Commands". The standard specifies a common syntax, command structure, and data formats, to be used with all instruments. It introduced generic commands (such as CONFigure and MEASure) that could be used with any instrument. These commands are grouped into subsystems. SCPI also defines several classes of instruments. For example, any controllable power supply would implement the same DCPSUPPLY base functionality class. Instrument classes specify which subsystems they implement, as well as any instrument-specific features. The physical hardware communications link (physical layer) is not defined by SCPI. While it was originally created for the IEEE-488.1 (GPIB) bus, SCPI can also be used with RS-232, RS-422, RS-485, USB, Ethernet, VXIbus, HiSLIP, etc. SCPI commands are ASCII textual strings, which are sent to the instrument over the physical layer. Commands are a series of one or more keywords, many of which take parameters. In the specification, keywords are written CONFigure: The entire keyword can be used, or it can be abbreviated to just the uppercase portion. Responses to query commands are typically ASCII strings. However, for bulk data, binary formats can be used. The SCPI specification consists of four volumes: Volume 1: "Syntax and Style", Volume 2: "Command Reference", Volume 3: "Data Interchange Format", Volume 4: "Instrument Classes". The specification was originally released as non-free printed manuals, then later as one free PDF file that includes all four volumes. SCPI history First released in 1990, SCPI originated as an additional layer for IEEE-488. IEEE-488.1 specified the physical and electrical bus, and IEEE-488.2 specified protocol and data format, but neither specified instrument commands. Different manufacturers, and even different models, of the same type of instrument would use different command sets. SCPI created a standard which could be common across all manufacturers and models. It requires use of the IEEE-488.2 data formats, but does not mandate the IEEE-488.1 bus. In 2002-2003, the SCPI Consortium voted to become part of the IVI Foundation (Interchangeable Virtual Instruments). IEEE 488.2 history In 1987, IEEE introduced IEEE 488.2-1987 specification "Standard Codes, Formats, Protocols, and Common Commands", it was later revised in 1992 as IEEE 488.2-1992. While IEEE 488.2 provided a device-independent syntax, there was still no standard for instrument-specific commands. Commands to control the same class of instrument, e.g., multimeters, would vary between manufacturers and even models. The United States Air Force, and later Hewlett-Packard, recognized this problem. In 1989, HP developed their TML language which was the forerunner to SCPI. The IEC developed their own standards in parallel with the IEEE, with IEC 60625-2-1993 (IEC 625). In 2004, the IEEE and IEC combined their respective standards into a "dual logo" IEEE/IEC standard IEC 60488-2-2004, Part 2: Codes, Formats, Protocols and Common Commands, replaces IEEE 488.2-1992 and IEC 60625-2-1993. Command syntax SCPI commands to an instrument may either perform a set operation (e.g. switching a power supply on) or a query operation (e.g. reading a voltage). Queries are issued to an instrument by appending a question-mark to the end of a command. Some commands can be used for both setting and querying an instrument. For example, the data-acquisition mode of an instrument could be set by using the ACQuire:MODe command or it could be queried by using the ACQuire:MODe? command. Some commands can both set and query an instrument at once. For example, the CAL? command runs a self-calibration routine on some equipment, and then returns the results of the calibration. Similar commands are grouped into a hierarchy or "tree" structure. For example, any instruction to read a measurement from an instrument will begin with "MEASure". Specific sub-commands within the hierarchy are nested with a colon (:) character. For example, the command to "Measure a DC voltage" would take the form MEASure:VOLTage:DC?, and the command to "Measure an AC current" would take the form MEASure:CURRent:AC?. :MEASure :VOLTage :DC? :AC? :CURRent :DC? :AC? ... Case Though the command syntax above shows commands in mixed case, SCPI is not case sensitive. For example, for VOLTage, all of the following are valid representations:VOLTAGE, voltage, Voltage, VoLtAgE. Abbreviating commands The command syntax shows some characters in a mixture of upper and lower case. Abbreviating the command to only sending the upper case has the same meaning as sending the upper and lower case command. For example, the command “SYSTem:COMMunicate:SERial:BAUD 2400” would set an RS-232 serial communications interface to 2400 bit/s. This could also alternatively be abbreviated “SYST:COMM:SER:BAUD 2400”. The query command “SYSTem:COMMunicate:SERial:BAUD?” or “SYST:COMM:SER:BAUD?” would instruct the instrument to report its current baud rate. The only valid commands are the short form and long form of each command, all other subset variations are invalid. For example, COMM (short form) and COMMUNICATE (long form) are valid, but COM, COMMUN, COMMUNIC subsets are invalid, also appended letters are invalid too, such as COMMUNICATED. Concatenating commands Multiple commands can be issued to an instrument in a single string. They are made of simple commands separated by a semicolon character (;). For example, the command to "Measure a DC voltage then measure an AC current" would be issued as MEASure:VOLTage:DC?;:MEASure:CURRent:AC?. Simple commands which start with a colon (:) are interpreted with respect to the root of the command tree. Otherwise, they refer implicitly to the last node of the previous command (unless they already begin with an asterisk). For example, :SOURce:FREQuency:STARt 100;STOP 200 is a shorthand for the message :SOURce:FREQuency:STARt 100;:SOURce:FREQuency:STOP 200 Arguments Some commands accept or require one or more additional arguments. Arguments are given after the command, and are separated from the command using a space. For example, the command to set the trigger mode of an instrument to "normal" may be given as "TRIGger:MODe NORMal". Here, the word "NORMal" is used as the argument to the "TRIGger:MODe" command. When multiple arguments are provided, the arguments are written as a comma-separated list. For example, a query command that performs an AC Volts measurement on a digital multimeter, using the meter's 10 VRMS measurement range, and displaying the measured voltage value with 4-1/2 digits of resolution, would be written as "MEASure:VOLTage:AC? 10,4". Integer arguments For commands that accept integer arguments, values may be specified in multiple computer number formats: decimal, hexadecimal, octal, binary. The last three formats are defined by IEEE 488.2, which SCPI is based upon. Decimal numbers (radix 10) aren't prefixed, hexadecimal numbers (radix 16) are prefixed with #H or #h, octal numbers (radix 8) with #Q or #q, and binary numbers (radix 2) with #B or #b. Hexadecimal digits may use either uppercase letters (ABCDEF), or lowercase letters (abcdef), or mixed case letters (aBcDeF). For octal, the letter "Q" was chosen instead of the letter "O" to minimize the visual confusion with the number "0" (zero). The following argument examples are numerically equivalent: Decimal: 26 Hexadecimal: #H1A or #h1a Octal: #Q32 or #q32 Binary: #B11010 or #b11010 488.2 commands Since SCPI was defined as an additional layer on top of the IEEE 488.2 specification, a SCPI compliant device should recognize various 488.2 commands too. These commands might also be known unofficially as asterisk commands (or star commands), because they all start with the asterisk character. According to section 4.1.1 of Volume 1 of SCPI, all SCPI devices must implement the following 488.2 commands. In the real world some low-end devices may only support a subset of these 488.2 commands, or may even accept the commands but not perform any operation. A user should check the official programmers manual for each device before assuming all of these 488.2 commands are supported. CLS ESE ESE? ESR? IDN? OPC OPC? RST SRE SRE? STB? TST? WAI According to section 4.1.2 of Volume 1 of SCPI, all other 488.2 commands not listed above are considered optional and not required by SCPI. AAD CAL? DDT DDT? DLF DMC EMC EMC? GMC? IST? LMC? LRN? OPT? PCB PMC PRE PRE? PSC PSC? PUD PUD? RCL RDT RDT? SAV TRG RMC SDS See also IEEE-488 (GPIB) Virtual Instrument Software Architecture (VISA) Instrument driver List of TCP and UDP port numbers - scpi-raw on TCP port 5025 and UDP port 5025 References External links SCPI Organization, official website Specifications SCPI-1999, Volume 1-4, 819 page PDF file, free download (doesn't include asterisk () commands, because they are specified in IEEE 488.2 & IEC 60488-2) IEEE 488.2-1992, 254 page PDF file, costs USD$52 in 2024 (superseded by IEEE/IEC 60488-2-2004) IEEE/IEC 60488-2-2004, 264 page PDF file, costs USD$373 in 2024 Programming Manual Examples Multimeters Tektronix DMM6500, 1202 page PDF file. Oscilloscopes Keysight InfiniiVision Families, 1896 page PDF file. Rohde-Schwarz MXO 4 Series, 848 page PDF file. Tektronix MSO 4/5/6 Families, 2050 page PDF file. Electronic engineering Electronics standards Input/output Electronic test equipment	Standard Commands for Programmable Instruments	[ "Technology", "Engineering" ]	2,403	[ "Computer engineering", "Electronic test equipment", "Measuring instruments", "Electronic engineering", "Electrical engineering" ]
13,219,252	https://en.wikipedia.org/wiki/Zaurategrast	Zaurategrast (CDP323) is a small-molecule prodrug antagonist of the vascular cell adhesion molecule 1 (VCAM-1) binding to α4-integrins. It was originally developed by the British biopharmaceutical company Celltech plc. (now UCB S.A.) and was a putative new drug for oral treatment of multiple sclerosis. In October 2006, UCB and Biogen Idec announced a collaboration to jointly develop and commercialize zaurategrast for the treatment of multiple sclerosis and other potential indications. In June 2009, development of zaurategrast was discontinued due to discouraging results of a Phase II clinical trial. Mechanism of action The mechanism of action of zaurategrast were believed to rely on preventing immune cells to migrate from blood vessels through the vessel walls to reach various inflamed tissues, including the brain. This mechanism is thought to prevent overshooting immune reactions and subsequent tissue damage as seen during uncontrolled immune cell migration as in multiple sclerosis. Zaurategrast has the same mechanism of action as the monoclonal antibody natalizumab. Results in animal models Zaurategrast was investigated in chronic experimental autoimmune encephalomyelitis (EAE) in mice. The drug was effective when given prophylactically (i.e., before the disease was induced in mice) and when given therapeutically (i.e., after outbreak of the disease) and reduced the disease severity significantly. Clinical development The safety, tolerability, and pharmacokinetic profile of zaurategrast have been evaluated in 75 female and male healthy volunteers in three separate Phase 1 studies. Zaurategrast was well tolerated at oral doses up to 1000 mg given twice daily for 7 consecutive days with an adverse event profile comparable to that observed with placebo. There was no gender effect. The oral administration resulted in inhibition of VCAM-1 binding which could be maintained throughout a 12‑ or 24‑hour dose interval at well tolerated doses A Phase 2 study commenced in June 2007 in Europe and in the US. The study intends to enroll over 200 patients with relapsing MS who have failed earlier treatment with an interferon-beta and will compare two doses of the drug to placebo over a period of six months. The results are expected by the end of 2008., Preliminary interim efficacy analysis showed that patients enrolled in this clinical trial did not benefit as expected from zaurategrast compared to placebo after a six-month treatment period. No cases of progressive multifocal leukoencephalopathy were noted. References External links Listings in the US NIH trial registry Immunosuppressants Naphthyridines Propionic acids Organobromides Abandoned drugs Spiro compounds Cyclobutenes	Zaurategrast	[ "Chemistry" ]	601	[ "Organic compounds", "Spiro compounds", "Drug safety", "Abandoned drugs" ]
13,219,331	https://en.wikipedia.org/wiki/Export%20Land%20Model	The Export Land Model, or Export-Land Model, refers to work done by Dallas geologist Jeffrey Brown, building on the work of others, and discussed widely on The Oil Drum. It models the decline in oil exports that result when an exporting nation experiences both a peak in oil production and an increase in domestic oil consumption. In such cases, exports decline at a far faster rate than the decline in oil production alone. The Export Land Model is important to petroleum importing nations because when the rate of global petroleum production peaks and begins to decline, the petroleum available on the world market will decline much more steeply than the decline in total production. Theory As world oil exports approach (or pass) a global peak, the price of exported oil increases and further stimulates domestic economic growth and oil consumption in Export-Land countries, creating a positive feedback process between declining exports and higher prices. Eventually, however, the level of export decline outpaces the increasing oil price, slowing domestic growth. In some cases, an Export Land eventually becomes a net importer. It is unlikely that an Export Land would constrain domestic consumption to help importing countries. In fact, many oil exporting countries subsidize domestic consumption below price levels defined by the world market. Hypothetical example Given a hypothetical oil producing country (known by the model as an Export Land) that produces , consumes , and exports to oil consuming countries around the world, the model would be applied as such (illustrated in the graph above): Export Land hits the point of Peak Oil production, and over a five-year period production drops by 25%. Over the same time period, Export Land's consumption increases by 20% to 1.2 mbpd. This causes Export Land's net exports over the five-year period to fall from 1 mbpd to 0.3 mbpd, a decrease of 70% -- resulting from a combination of increasing domestic consumption in Export Land and a 25% drop in production. Counter-intuitively, the fractional decline in exports is much greater than the sum of the fractional increase in domestic consumption and the fractional decline in production. Real-world examples Several real-world nations exhibit the characteristics of the Export Land Model as pictured in the image gallery above. These four nations exhibit increasing domestic consumption along with declining production. Indonesia has already shifted from oil exporter to oil importer while Egypt is hovering on the brink. Malaysia and Mexico also have the hallmarks of the Export Land Model. Within 5 years, Mexico (the second biggest exporter of oil to the US) may become a net oil importer. Other nations where this may soon happen include Iran, Algeria and Malaysia. A recent report from CIBC World Markets also indicates that as much as 40% of Saudi Arabia's expected production increases will be offset by rising internal demand by 2010, and Iranian exports will decline by more than 50% for similar reasons. This report indicates that similar market pressures could reduce net worldwide oil exports by (about 3%). Nations may also reach their peak of oil production without fitting the Export Land model. For example, the United Kingdom began importing oil in 2006, after decades of exporting, due to declining production. But as domestic consumption in the UK has remained essentially unchanged for the last 20 years, their rising import levels essentially match their falling production levels. Similarly, Norway's exports began declining in 2001, but at the same rate as their production because their domestic consumption was also not growing. Unlike many exporters, these two countries don't subsidize local market oil price and have high fuel prices by world standards, thus one of the premises of the export land model (that domestic consumption should not be affected by world market price) does not apply to those countries. See also Energy development Energy security Oil price increases since 2003 Oil reserves World energy resources and consumption References Peak oil Petroleum politics	Export Land Model	[ "Chemistry" ]	791	[ "Petroleum", "Petroleum politics" ]
13,219,793	https://en.wikipedia.org/wiki/New%20Alchemy%20Institute	The New Alchemy Institute was a research center that did pioneering investigation into organic agriculture, aquaculture and bioshelter design between 1969 and 1991. It was founded by John Todd, Nancy Jack Todd, and William McLarney. Its purpose was to research human support systems of food, water, and shelter and to completely rethink how these systems were designed. Purpose of the Institute The New Alchemy Institute was founded on a , former dairy farm in Hatchville, part of Falmouth, Massachusetts, on Cape Cod. Their stated aim was to do research on behalf of the planet: "Among our major tasks is the creation of ecologically derived human support systems - renewable energy, agriculture, aquaculture, housing and landscapes. The strategies we research emphasize a minimal reliance on fossil fuels and operate on a scale accessible to individuals, families and small groups. It is our belief that ecological and social transformations must take place at the lowest functional levels of society if humankind is to direct its course towards a greener, saner world. Our programs are geared to produce not riches, but rich and stable lives, independent of world fashion and the vagaries of international economics. The New Alchemists work at the lowest functional level of society on the premise that society, like the planet itself, can be no healthier than the components of which it is constructed. The urgency of our efforts is based on our belief that the industrial societies which now dominate the world are in the process of destroying it." (Fall 1970, Bulletin of the New Alchemists. ) Areas of research Bioshelters A bioshelter is a solar greenhouse that is managed as a self-contained ecosystem. The groupings of plants, animals, soil and insects are selected so that closed loops of life cycles, materials, water, and energy are created, and require minimal inputs from outside the system. They emulate natural rhythms of growth and cycling of nutrients. New Alchemy built several bioshelters: "The Ark" located at the property in Hatchville, Massachusetts, United States "The Ark" located at Spry Point, Prince Edward Island, Canada was built in 1976 and demolished in the late 1990s. Organic agriculture New Alchemy investigated the practices of organic agriculture for both field crops, and greenhouse growing. They researched intensive gardening, biological pest control, cover cropping, irrigation using fish pond water, perennial food crops, and tree crops. Aquaculture New Alchemy experimented with growing edible fish in ponds in the bioshelters. The solar aquaculture ponds were above-ground, translucent tanks. The fertile pond water was used for irrigating the crops in the greenhouses. This proved to be a successful way to raise edible fish, floating hydroponic crops, and irrigated greenhouse food crops. Ideological basis The scientists working at New Alchemy were determined to rethink how human support systems were designed. They looked to nature as the ultimate designer, using careful observation of natural cycles and processes as the template for creating truly sustainable systems. Publications The research conducted at New Alchemy was documented in a series of journals and technical bulletins. A complete list is available at: New Alchemy Institute References External links New Alchemy Institute Ocean Arks International Environmental research institutes Research institutes in Massachusetts Research institutes in Canada	New Alchemy Institute	[ "Environmental_science" ]	679	[ "Environmental research institutes", "Environmental research" ]
13,221,438	https://en.wikipedia.org/wiki/Stephen%20Parke	Stephen Parke is a New Zealand-American theoretical physicist. He is a distinguished scientist and former head (2010–2015) of the Theoretical Physics Department at the Fermi National Accelerator Laboratory Batavia, Illinois. Born in Gisborne, New Zealand, Parke attended Campion College, Gisborne and St Peter's College, Auckland. He did his undergraduate studies, mathematics and physics, at the University of Auckland in New Zealand where his mentor was Dan Walls. He obtained a Fulbright Travel Grant and was awarded a Frank Knox Memorial Fellowship to attend graduate school at Harvard University. He was a graduate student of Sidney Coleman, obtaining a PhD in theoretical particle physics in 1980. He held a postdoctoral fellowship at the Stanford Linear Accelerator Center (1980–1983) collaborating with Sidney Drell before moving to the Fermi National Accelerator Laboratory as an Associate Scientist. He became an APS fellow in 1996 and in 2018 he was awarded a Doctorate of Science from the University of Auckland for his work on "Amplitudes in Gauge Theories". Parke's Erdos number is 3, having written papers with both Sidney Coleman and mathematician Terence Tao. Contributions to physics He is an originator of Parke–Taylor amplitudes, which he developed with his colleague, Tomasz Taylor. Parke-Taylor amplitudes represent a new approach to computing scattering amplitudes in quantum chromodynamics using symmetry methods such as supersymmetry. This work was further extended in collaboration with Michelangelo Mangano and Xu Zhan. The discovery of the Parke-Taylor amplitudes ignited the amplitude revolution: a major advance in our understanding and calculability of scattering amplitudes in gauge theories, the foundation of particle physics. This advance is discussed in detail in Chapter 11 of Graham Farmelo's book "The Universe speaks in Numbers". Parke's important Amplitude papers are linked here. With collaborator Gregory Mahon and others he pioneered the study of spin correlations in Top Quark pair production at Hadron collider which has lead to the confirmation of quantum entanglement at the highest possible energy by ATLAS and CMS. Here is a link to his important Top Quark papers. Parke is also an expert on neutrino physics. He gave the first analytical solution to the MSW effect including the non-adabatic region and has made important contributions to the physics of Long baseline Neutrino Oscillation experiments, T2K, NOvA, Hyper-Kamiokande and DUNE as well as the reactor experiments RENO, Daya Bay and JUNO. Here is a link to his important Neutrino papers. He has also written papers on Magnetic Monopoles and the decay of the false vacuum in curved space time. Personnal Life Parke's father was the orthopedic surgeon William Parke and mother Muriel Parke (née Stephens), a school teacher. His parents both born in Liverpool immigrated from the UK to New Zealand in 1949 to help with the polio epidemic raging in New Zealand at that time. Parke is a nephew of marine botanist Mary Parke. Parke is married to Winifred Haun, the MacArthur Foundation and 3Arts award-winning Choreographer and artistic director of the contemporary dance company Winifred Haun & Dancers. WH&D is one of the more diverse and innovative dance companies in Chicago. They have three amazing daughters: Athena, Iris and Selene. See also List of alumni of St Peter's College, Auckland for more biographical details References External links Parke's scientific publications are available on the INSPIRE-HEP Literature Database . HEPNames profile: Stephen Parke Stephen Parke at Fermilab Theoretical Physics Department Particle physicists Neutrino physicists American theoretical physicists Fellows of the American Physical Society 20th-century American physicists 21st-century American physicists Harvard University alumni American people of New Zealand descent New Zealand scientists New Zealand physicists University of Auckland alumni People from Gisborne, New Zealand Living people People educated at St Peter's College, Auckland Theoretical physicists Th People associated with Fermilab People educated at Campion College, Gisborne Year of birth missing (living people)	Stephen Parke	[ "Physics" ]	846	[ "Theoretical physics", "Theoretical physicists", "Particle physics", "Particle physicists" ]
13,221,513	https://en.wikipedia.org/wiki/Paul%20Mackenzie%20%28physicist%29	Paul B. Mackenzie (born 1950) is a theoretical physicist at the Fermi National Accelerator Laboratory. He did graduate work in physics at Cornell University where he was a student of G. Peter Lepage. He is an expert on Lattice Gauge Theory. He is the chair of the Executive Committee of USQCD, the US collaboration for developing the necessary supercomputing hardware and software for quantum chromodynamics formulated on a lattice. Selected publications Mackenzie's has published 71 scientific papers listed in the INSPIRE-HEP Literature Database. The most widely cited of them, "Viability of lattice perturbation theory" in Physical Review D 48 (5), pp. 2250–2264 (1993) has been cited 589 times by March 2009. The second most widely cited, "On the elimination of scale ambiguities in perturbative quantum chromodynamics " Physical Review D 28 (1), pp. 228–235 (1983) has been cited 406 times. Both papers are with Lepage, and the second also with Stan Brodsky. References External links Fermilab Theoretical Physics Department Fermilab Homepage for Paul Mackenzie People associated with Fermilab 20th-century American physicists Particle physicists Theoretical physicists Living people 1950 births	Paul Mackenzie (physicist)	[ "Physics" ]	263	[ "Theoretical physics", "Particle physicists", "Particle physics", "Theoretical physicists" ]
13,222,142	https://en.wikipedia.org/wiki/Audio%20equipment%20testing	Audio equipment testing is the measurement of audio quality through objective and/or subjective means. The results of such tests are published in journals, magazines, whitepapers, websites, and in other media. Those who test and evaluate equipment can be roughly divided into two groups: "Objectivists", who believe that all perceivable differences in audio equipment can be explained scientifically through measurement and double-blind listening tests; and the "Subjectivists", who believe that the human ear is capable of hearing details and differences that cannot be directly measured. Summary of Objective versus Subjective Audiophiles, in general: Both agree that measurements are not a substitute for listening tests. Both agree that different audio components may have different sound qualities. Disagree that subjective listeners can overcome placebo and confirmation bias in non-blind listening tests. Disagree about whether perceived sound quality can be measured through objective means. Objectivists Objectivists believe that audio components and systems must pass rigorously conducted double-blind tests and meet specified performance requirements in order to validate the claims made by their proponents. Objectivists point out that properly conducted and interpreted double-blind tests fail to support subjectivists' claims of significant or even subtle sonic differences between devices in cases where measurements predict that there should be no sonic differences in normal music listening. Objectivists feel that subjectivists often lack engineering training, technical knowledge, and objective credentials, but nevertheless make authoritative claims about product performance. Objectivists are likely to stress the importance of accounting for the influence of placebo and confirmation bias in subjective listening tests . Objectivists reject arguments that are based on accepted physical principles but applied to circumstances where they are irrelevant. For instance, the skin effect, which relates the efficiency of cables to the frequency transmitted, is often applied to audio frequencies where it is insignificant . Objectivists believe that subjectivists' preferences are often driven by gullibility and fashion—e.g., the late eighties' vogue for marking the edges of CDs with a green felt marker or suspending cables above the floor on small racks—and bear no relation to well-known laws of physics. Objectivists claim that subjectivists often reject attempts to notate differences in sound using objective measurements, despite the evidence of their effectiveness. Because measured audio distortion is higher in electromechanical components such as microphones, turntables, tonearms, phono cartridges, and loudspeakers than in purely electronic components such as preamplifiers and power amplifiers, objectivists generally do not accept that very subtle differences in the latter can have an appreciable effect on the perceived quality of reproduced sound. British audio equipment designer Peter Baxandall, who is often considered an objectivist, has written, "I ... confidently maintain that all first-class, competently designed amplifiers, tested under completely fair and carefully controlled conditions, including the avoidance of overloading, sound absolutely indistinguishable on normal programme material no matter how refined the listening tests, or the listeners, may be; and that when an inferior amplifier is compared with a very good one and a subjective quality difference is genuinely and reliably established, it is always possible, by straightforward scientific investigation, to find a rational explanation for this difference." Baxandall also proposed a "cancellation test", which he claimed would prove his point. Subjectivists Subjectivist Harry Pearson, long-time editor of The Absolute Sound, an audiophile magazine, has stated: "We believe that the sound of music, unamplified, occurring in a real space is a philosophic absolute against which we may judge the performance of devices designed to reproduce music." Subjectivists rely on demonstrations and comparisons but believe there are problems in applying double-blind methods to comparisons of audio devices. They believe that a relaxing environment and sufficient time measured in days or weeks is necessary for the discriminating ear to do its work. They believe that careful individual listening is an appropriate tool for discovering the true worth of a device or treatment, and will generally acquire equipment that suits their own listening or style preferences as opposed to measurable equipment performance. They are also likely to de-emphasize or ignore the potential impact of placebo and confirmation bias on subjective listening tests. Subjectivists claim that experienced listeners can be relied upon for valid advice on how equipment sounds. British Hi-fi critic, Martin Colloms, writes that "the ability to assess sound quality is not a gift, nor is it the feature of a hyperactive imagination; it is simply a learned skill", which can be acquired by example, education and practice. In any event, the eventual purchase decision will be made by the end-user, whose "perception is reality" and can be influenced by factors other than the equipment's actual performance. Opposing viewpoints The most significant difference between the two groups is that subjectivists claim there is a limit to what can be tested using objective measurements, while objectivists believe that since blind testing is the gold standard of all science, perceived sound quality should not be exempt from objective measurements. Objectivists tend to see the subjectivists as irrational and prone to gullibility, while subjectivists often dismiss objectivists as simple "meter men" who lack a nuanced appreciation of sound. Although the debate can be heated in certain quarters, both groups seek optimal listening experiences, and in some cases, the findings of one group has informed the other. Objectivists argue that vacuum-tube amplifiers often exhibit lower-fidelity than solid-state designs, and that in addition to their substantially higher total harmonic distortion level, they require rebiasing, tend to be less reliable, less powerful, generate more heat, and are usually more expensive. Subjectivists are often argue that while tube electronics are less linear than solid-state electronics at high-signal levels, they are much more linear at low-signal levels (less than one watt) and that many musical signals spend much of their time at these low levels. However, in cases where the subjectivists' claims can be verified by objective measure, it could not be considered a strictly "subjective" position. A more literally subjectivist argument is that listeners may be able to discern pleasurable benefits from tube equipment that would escape any attempt at objective measurement. Objectivists claim that digital sound can have higher fidelity than analog sound because it lacks clicks, pops, wow, flutter, audio feedback, degradation, generational loss, and rumble, has a higher signal-to-noise ratio, has a wider dynamic range, has less total harmonic distortion, and has a flatter and more extended frequency response. Subjectivists have argued that the process of converting a bit-stream to an analog waveform requires heavy filtering to remove spurious high-frequency information and that it should be expected that such filtering should involve some signal degradation and a large amount of phase shift in the passband. They point out that commonly used consumer-grade digital-to-analog converters (DACs) exhibit poor linearity at low levels. Both of these problems have since been verified by objective measure, and were then addressed by such solutions as digital filtering, oversampling, and the use of DACs operating at 20-bit (or higher) resolution. Today, many objectivists and subjectivists may agree that a preference for analog formats is often rooted in pleasing and familiar distortions and artifacts. At the same time, members of both camps might also agree that the best historical analog formats have often displayed great levels of audio fidelity as well. Musician Neil Young is a harsh critic of the sound of the original CD format but has expressed approval for the sound of higher definition formats such as SACD, which has a greater margin between its ideal behavior and the theoretical limits of human hearing. However, many independent listening tests and mathematical studies have shown that Young's assertions are basically untrue. Regardless, in 2011, Neil Young filed paperwork to trademark his own developing high-resolution audio player. Objectivists and Subjectivist were once at odds about the importance of total harmonic distortion. Both groups now seem to agree that the distribution of harmonic distortion can be important in perceived sound quality. This is another case where subjective opinion was eventually verified by objective measure, and taken into account by objectivist engineers. Although this is no longer technically a point of contention, objectivists may be more likely to stress the importance of reducing total harmonic distortion in a system, while subjectivists may more often stress the importance on creating a more pleasing distribution of harmonic distortion. Difficulty of testing It is difficult, but very important, to match sound levels before comparing systems, as minute increases in loudness—more than 0.15 dB or 0.1 dB—have been demonstrated to cause perceived improvements in sound quality. Listening tests are subjected to many variables, and results are notoriously unreliable. Thomas Edison, for example, showed that large audiences responded favorably when presented both live performances by artists and reproductions by his recording system, which today would be regarded as primitive in quality. Similarly, results of component evaluation between various listeners or even the same listener under different circumstances cannot be easily replicated or standardized. Similarly, the acoustic behavior of the listening room—the interaction between loudspeakers and the room's acoustics—and the interaction between an electromechanical device (loudspeaker) and an electronic device (amplifier) are subjected to many more variables than between electronic components. Thus the "difference" in sound quality between amplifiers is actually the ability of an amplifier to interface well with loudspeakers or a lucky combination of loudspeaker, amplifier, and room that works well together. The introduction of switching apparatus, with either metal connection (mechanical switches) or electronic processing (solid-state switches), may, some believe, obscure the differences between the two signal sources being tested. Skepticism advocate James Randi has offered a $1 million prize to subjectivists who can prove their most dubious claims through scientific blind testing. The prize remains unclaimed. See also Test CD References External links The Audio Critic - Thirty-year publication, now online only, with in-depth independent verification of vendors' claims. Stereophile - Largest, oldest, and most read subjectivist magazine includes online reviews and articles. Audiocheck - Site for testing audio equipment and speakers YouTube - 1-minute audio test for speakers and headphones PGY-I2S - I2S Audio Testing Software (Physical Layer to Audio experience) Audio electronics	Audio equipment testing	[ "Engineering" ]	2,153	[ "Audio electronics", "Audio engineering" ]
13,222,289	https://en.wikipedia.org/wiki/Roman%20concrete	Roman concrete, also called , was used in construction in ancient Rome. Like its modern equivalent, Roman concrete was based on a hydraulic-setting cement added to an aggregate. Many buildings and structures still standing today, such as bridges, reservoirs and aqueducts, were built with this material, which attests to both its versatility and its durability. Its strength was sometimes enhanced by the incorporation of pozzolanic ash where available (particularly in the Bay of Naples). The addition of ash prevented cracks from spreading. Recent research has shown that the incorporation of mixtures of different types of lime, forming conglomerate "clasts" allowed the concrete to self-repair cracks. Roman concrete was in widespread use from about 150 BC; some scholars believe it was developed a century before that. It was often used in combination with facings and other supports, and interiors were further decorated by stucco, fresco paintings, or coloured marble. Further innovative developments in the material, part of the so-called concrete revolution, contributed to structurally complicated forms. The most prominent example of these is the Pantheon dome, the world's largest and oldest unreinforced concrete dome. Roman concrete differs from modern concrete in that the aggregates often included larger components; hence, it was laid rather than poured. Roman concretes, like any hydraulic concrete, were usually able to set underwater, which was useful for bridges and other waterside construction. Historic references Vitruvius, writing around 25 BC in his Ten Books on Architecture, distinguished types of materials appropriate for the preparation of lime mortars. For structural mortars, he recommended pozzolana ( in Latin), the volcanic sand from the beds of Pozzuoli, which are brownish-yellow-gray in colour in that area around Naples, and reddish-brown near Rome. Vitruvius specifies a ratio of 1 part lime to 3 parts pozzolana for mortar used in buildings and a 1:2 ratio for underwater work. The Romans first used hydraulic concrete in coastal underwater structures, probably in the harbours around Baiae before the end of the 2nd century BC. The harbour of Caesarea is an example (22-15 BC) of the use of underwater Roman concrete technology on a large scale, for which enormous quantities of pozzolana were imported from Puteoli. For rebuilding Rome after the fire in 64 AD which destroyed large portions of the city, Nero's new building code largely called for brick-faced concrete. This appears to have encouraged the development of the brick and concrete industries. Material properties Roman concrete, like any concrete, consists of an aggregate and hydraulic mortar, a binder mixed with water that hardens over time. The composition of the aggregate varied, and included pieces of rock, ceramic tile, lime clasts, and brick rubble from the remains of previously demolished buildings. In Rome, readily available tuff was often used as an aggregate. Gypsum and quicklime were used as binders. Volcanic dusts, called pozzolana or "pit sand", were favoured where they could be obtained. Pozzolana makes the concrete more resistant to salt water than modern-day concrete. Pozzolanic mortar had a high content of alumina and silica. Research in 2023 found that lime clasts, previously considered a sign of poor aggregation technique, react with water seeping into any cracks. This produces reactive calcium, which allows new calcium carbonate crystals to form and reseal the cracks. These lime clasts have a brittle structure that was most likely created in a "hot-mixing" technique with quicklime rather than traditional slaked lime, causing cracks to preferentially move through the lime clasts, thus potentially playing a critical role in the self-healing mechanism. Concrete and, in particular, the hydraulic mortar responsible for its cohesion, was a type of structural ceramic whose utility derived largely from its rheological plasticity in the paste state. The setting and hardening of hydraulic cements derived from hydration of materials and the subsequent chemical and physical interaction of these hydration products. This differed from the setting of slaked lime mortars, the most common cements of the pre-Roman world. Once set, Roman concrete exhibited little plasticity, although it retained some resistance to tensile stresses.The setting of pozzolanic cements has much in common with setting of their modern counterpart, Portland cement. The high silica composition of Roman pozzolana cements is very close to that of modern cement to which blast furnace slag, fly ash, or silica fume have been added. The strength and longevity of Roman 'marine' concrete is understood to benefit from a reaction of seawater with a mixture of volcanic ash and quicklime to create a rare crystal called tobermorite, which may resist fracturing. As seawater percolated within the tiny cracks in the Roman concrete, it reacted with phillipsite naturally found in the volcanic rock and created aluminous tobermorite crystals. The result is a candidate for "the most durable building material in human history". In contrast, modern concrete exposed to saltwater deteriorates within decades. The Roman concrete at the Tomb of Caecilia Metella is another variation higher in potassium that triggered changes that "reinforce interfacial zones and potentially contribute to improved mechanical performance". Seismic technology For an environment as prone to earthquakes as the Italian peninsula, interruptions and internal constructions within walls and domes created discontinuities in the concrete mass. Portions of the building could then shift slightly when there was movement of the earth to accommodate such stresses, enhancing the overall strength of the structure. It was in this sense that bricks and concrete were flexible. It may have been precisely for this reason that, although many buildings sustained serious cracking from a variety of causes, they continue to stand to this day. Another technology used to improve the strength and stability of concrete was its gradation in domes. One example is the Pantheon, where the aggregate of the upper dome region consists of alternating layers of light tuff and pumice, giving the concrete a density of . The foundation of the structure used travertine as an aggregate, having a much higher density of . Modern use Scientific studies of Roman concrete since 2010 have attracted both media and industry attention. Because of its unusual durability, longevity, and lessened environmental footprint, corporations and municipalities are starting to explore the use of Roman-style concrete in North America. This involves replacing the volcanic ash with coal fly ash that has similar properties. Proponents say that concrete made with fly ash can cost up to 60% less, because it requires less cement. It also has a reduced environmental footprint, due to its lower cooking temperature and much longer lifespan. Usable examples of Roman concrete exposed to harsh marine environments have been found to be 2000 years old with little or no wear. In 2013, the University of California Berkeley published an article that described for the first time the mechanism by which the suprastable calcium-aluminium-silicate-hydrate compound binds the material together. During its production, less carbon dioxide is released into the atmosphere than any modern concrete production process. It is no coincidence that the walls of Roman buildings are thicker than those of modern buildings. However, Roman concrete was still gaining its strength for several decades after construction had been completed. See also Literature References External links Ancient Roman architecture Concrete Concrete buildings and structures Building materials Masonry Pavements Sculpture materials Ancient inventions Architecture in Italy Architectural history Ancient Roman construction techniques	Roman concrete	[ "Physics", "Engineering" ]	1,531	[ "Structural engineering", "Architectural history", "Masonry", "Building engineering", "Architecture", "Construction", "Materials", "Concrete", "Matter", "Building materials" ]
13,222,629	https://en.wikipedia.org/wiki/ADP-ribosylation	ADP-ribosylation is the addition of one or more ADP-ribose moieties to a protein. It is a reversible post-translational modification that is involved in many cellular processes, including cell signaling, DNA repair, gene regulation and apoptosis. Improper ADP-ribosylation has been implicated in some forms of cancer. It is also the basis for the toxicity of bacterial compounds such as cholera toxin, diphtheria toxin, and others. History The first suggestion of ADP-ribosylation surfaced during the early 1960s. At this time, Pierre Chambon and coworkers observed the incorporation of ATP into hen liver nuclei extract. After extensive studies on the acid insoluble fraction, several different research laboratories were able to identify ADP-ribose, derived from NAD+, as the incorporated group. Several years later, the enzymes responsible for this incorporation were identified and given the name poly(ADP-ribose)polymerase. Originally, this group was thought to be a linear sequence of ADP-ribose units covalently bonded through a ribose glycosidic bond. It was later reported that branching can occur every 20 to 30 ADP residues. The first appearance of mono(ADP-ribosyl)ation occurred a year later during a study of toxins: the diphtheria toxin of Corynebacterium diphtheriae was shown to be dependent on NAD+ in order for it to be completely effective, leading to the discovery of enzymatic conjugation of a single ADP-ribose group by mono(ADP-ribosyl)transferase. It was initially thought that ADP-ribosylation was a post translational modification involved solely in gene regulation. However, as more enzymes with the ability to ADP-ribosylate proteins were discovered, the multifunctional nature of ADP-ribosylation became apparent. The first mammalian enzyme with poly(ADP-ribose)transferase activity was discovered during the late 1980s. For the next 15 years, it was thought to be the only enzyme capable of adding a chain of ADP-ribose in mammalian cells. During the late 1980s, ADP-ribosyl cyclases, which catalyze the addition of cyclic-ADP-ribose groups to proteins, were discovered. Finally, sirtuins, a family of enzymes that also possess NAD+-dependent deacylation activity, were discovered to also possess mono(ADP-ribosyl)transferase activity. Catalytic mechanism The source of ADP-ribose for most enzymes that perform this modification is the redox cofactor NAD+. In this transfer reaction, the N-glycosidic bond of NAD+ that bridges the ADP-ribose molecule and the nicotinamide group is cleaved, followed by nucleophilic attack by the target amino acid side chain. (ADP-ribosyl)transferases can perform two types of modifications: mono(ADP-ribosyl)ation and poly(ADP-ribosyl)ation. Mono(ADP-ribosyl)ation Mono(ADP-ribosyl)transferases commonly catalyze the addition of ADP-ribose to arginine side chains using a highly conserved R-S-EXE motif of the enzyme. The reaction proceeds by breaking the bond between nicotinamide and ribose to form an oxonium ion. Next, the arginine side chain of the target protein then acts a nucleophile, attacking the electrophilic carbon adjacent to the oxonium ion. In order for this step to occur, the arginine nucleophile is deprotonated by a glutamate residue on the catalyzing enzyme. Another conserved glutamate residue forms a hydrogen bond with one of the hydroxyl groups on the ribose chain to further facilitate this nucleophilic attack. As a result of the cleavage reaction, nicotinamide is released. The modification can be reversed by (ADP-ribosyl)hydrolases, which cleave the N-glycosidic bond between arginine and ribose to release ADP-ribose and unmodified protein; NAD+ is not restored by the reverse reaction. Poly(ADP-ribosyl)ation Poly(ADP-ribose)polymerases (PARPs) are found mostly in eukaryotes and catalyze the transfer of multiple ADP-ribose molecules to target proteins. As with mono(ADP-ribosyl)ation, the source of ADP-ribose is NAD+. PARPs use a catalytic triad of His-Tyr-Glu to facilitate binding of NAD+ and positioning of the end of the existing poly(ADP-ribose) chain on the target protein; the Glu facilitates catalysis and formation of a (1''→2') O-glycosidic linkage between two ribose molecules. There are several other enzymes that recognize poly(ADP-ribose) chains, hydrolyse them or form branches; over 800 proteins have been annotated to contain the loosely defined poly(ADP-ribose) binding motif; therefore, in addition to this modification altering target protein conformation and structure, it may also be used as a tag to recruit other proteins or for regulation of the target protein. Amino acid specificity Many different amino acid side chains have been described as ADP-ribose acceptors. From a chemical perspective, this modification represents protein glycosylation: the transfer of ADP-ribose occurs onto amino acid side chains with a nucleophilic oxygen, nitrogen, or sulfur, resulting in N-, O-, or S-glycosidic linkage to the ribose of the ADP-ribose. Originally, acidic amino acids (glutamate and aspartate) were described as the main sites of ADP-ribosylation. However, many other ADP-ribose acceptor sites such as serine, arginine, cysteine, lysine, diphthamide, phosphoserine, and asparagine have been identified in subsequent works. Function Apoptosis During DNA damage or cellular stress PARPs are activated, leading to an increase in the amount of poly(ADP-ribose) and a decrease in the amount of NAD+. For over a decade it was thought that PARP1 was the only poly(ADP-ribose)polymerase in mammalian cells, therefore this enzyme has been the most studied. Caspases are a family of cysteine proteases that are known to play an essential role in programmed cell death. This protease cleaves PARP-1 into two fragments, leaving it completely inactive, to limit poly(ADP-ribose) production. One of its fragments migrates from the nucleus to the cytoplasm and is thought to become a target of autoimmunity. During caspase-independent apoptosis, also called parthanatos, poly(ADP-ribose) accumulation can occur due to activation of PARPs or inactivation of poly(ADP-ribose)glycohydrolase, an enzyme that hydrolyses poly(ADP-ribose) to produce free ADP-ribose. Studies have shown poly(ADP-ribose) drives the translocation of the apoptosis inducing factor protein to the nucleus where it will mediate DNA fragmentation. It has been suggested that if a failure of caspase activation under stress conditions were to occur, necroptosis would take place. Overactivation of PARPs has led to a necrotic cell death regulated by the tumor necrosis factor protein. Though the mechanism is not yet understood, PARP inhibitors have been shown to affect necroptosis. Gene regulation ADP-ribosylation can affect gene expression at nearly every level of regulation, including chromatin organization, transcription factor recruitment and binding, and mRNA processing. The organization of nucleosomes is key to regulation of gene expression: the spacing and organization of nucleosomes changes what regions of DNA are available for transcription machinery to bind and transcribe DNA. PARP1, a poly-ADP ribose polymerase, has been shown to affect chromatin structure and promote changes in the organization of nucleosomes through modification of histones. PARPs have been shown to affect transcription factor structure and cause recruitment of many transcription factors to form complexes at DNA and elicit transcription. Mono(ADP-ribosyl)transferases are also shown to affect transcription factor binding at promoters. For example, PARP14, a mono (ADP-ribosyl)transferase, has been shown to affect STAT transcription factor binding. Other (ADP-ribosyl)transferases have been shown to modify proteins that bind mRNA, which can cause silencing of that gene transcript. DNA repair Poly(ADP-ribose)polymerases (PARPs) can function in DNA repair of single strand breaks as well as double strand breaks. In single-strand break repair (base excision repair) the PARP can either facilitate removal of an oxidized sugar or strand cleavage. PARP1 binds the single-strand breaks and pulls any nearby base excision repair intermediates close. These intermediates include XRCC1 and APLF and they can be recruited directly or through the PBZ domain of the APLF. This leads to the synthesis of poly(ADP-ribose). The PBZ domain is present in many proteins involved in DNA repair and allows for the binding of the PARP and thus ADP-ribosylation which recruits repair factors to interact at the break site. PARP2 is a secondary responder to DNA damage but serves to provide functional redundancy in DNA repair. There are many mechanisms for the repair of damaged double stranded DNA. PARP1 may function as a synapsis factor in alternative non-homologous end joining. Additionally, it has been proposed that PARP1 is required to slow replication forks following DNA damage and promotes homologous recombination at replication forks that may be dysfunctional. It is possible that PARP1 and PARP3 work together in repair of double-stranded DNA and it has been shown that PARP3 is critical for double-stranded break resolution. There are two hypotheses by which PARP1 and PARP3 coincide. The first hypothesis states that the two (ADP-ribosyl)transferases serve to function for each other's inactivity. If PARP3 is lost, this results in single-strand breaks, and thus the recruitment of PARP1. A second hypothesis suggests that the two enzyme work together; PARP3 catalyzes mono(ADP-ribosyl)ation and short poly(ADP-ribosyl)ation and serves to activate PARP1. The PARPs have many protein targets at the site of DNA damage. KU protein and DNA-PKcs are both double-stranded break repair components with unknown sites of ADP-ribosylation. Histones are another protein target of the PARPs. All core histones and linker histone H1 are ADP-ribosylated following DNA damage. The function of these modifications is still unknown, but it has been proposed that ADP-ribosylation modulates higher-order chromatin structure in efforts to facilitate more accessible sites for repair factors to migrate to the DNA damage. Protein degradation The ubiquitin-proteasome system (UPS) figures prominently in protein degradation. The 26S proteasome consists of a catalytic subunit (the 20S core particle), and a regulatory subunit (the 19S cap). Poly-ubiquitin chains tag proteins for degradation by the proteasome, which causes hydrolysis of tagged proteins into smaller peptides. Physiologically, PI31 attacks 20S catalytic domain of 26S Proteasome that results in decreased proteasome activity. (ADP-ribosyl)transferase Tankyrase (TNKS) causes ADP-ribosylation of PI31 which in turn increases the proteasome activity. Inhibition of TNKs further shows the reduced 26S Proteasome assembly. Therefore, ADP-ribosylation promotes 26S Proteasome activity in both Drosophila and human cells. Enzyme regulation The activity of some enzymes is regulated by ADP-ribosylation. For instance, the activity of Rodospirillum rubrum di-nitrogenase-reductase is turned off by ADP-ribosylation of an arginine residue, and reactivated by the removal of the ADP-ribosyl group. Clinical significance Cancer PARP1 is involved in base excision repair (BER), single- and double-strand break repair, and chromosomal stability. It is also involved in transcriptional regulation through its facilitation of protein–protein interactions. PARP1 uses NAD+ in order to perform its function in apoptosis. If a PARP becomes overactive the cell will have decreased levels of NAD+ cofactor as well as decreased levels of ATP and thus will undergo necrosis. This is important in carcinogenesis because it could lead to the selection of PARP1 deficient cells (but not depleted) due to their survival advantage during cancer growth. Susceptibility to carcinogenesis under PARP1 deficiency depends significantly on the type of DNA damage incurred. There are many implications that various PARPs are involved in preventing carcinogenesis. As stated previously, PARP1 and PARP2 are involved in BER and chromosomal stability. PARP3 is involved in centrosome regulation. Tankyrase is another (ADP-ribosyl)polymerase that is involved in telomere length regulation. PARP1 inhibition has also been widely studied in anticancer therapeutics. The mechanism of action of a PARP1 inhibitor is to enhance the damage done by chemotherapy on the cancerous DNA by disallowing the reparative function of PARP1 in BRCA1/2 deficient individuals . PARP14 is another ADP-ribosylating enzyme that has been well-studied in regards to cancer therapy targets; it is a signal transducer and activator of STAT6 transcription-interacting protein, and was shown to be associated with the aggressiveness of B-cell lymphomas. Bacterial toxins Bacterial ADP-ribosylating exotoxins (bAREs) covalently transfer an ADP-ribose moiety of NAD+ to target proteins of infected eukaryotes, to yield nicotinamide and a free hydrogen ion. bAREs are produced as enzyme precursors, consisting of a "A" and "B" domains: the "A" domain is responsible for ADP-ribosylation activity; and, the "B" domain for translocation of the enzyme across the membrane of the cell. These domains can exist in concert in three forms: first, as single polypeptide chains with A and B domains covalently linked; second, in multi-protein complexes with A and B domains bound by non-covalent interactions; and, third, in multi-protein complexes with A and B domains not directly interacting, prior to processing. Upon activation, bAREs ADP-ribosylate any number of eukaryotic proteins; such mechanism is crucial to the instigation of the diseased states associated with ADP-ribosylation. GTP-binding proteins, in particular, are well-established in bAREs pathophysiology. For examples, cholera and heat-labile enterotoxin target the α-subunit of Gs of heterotrimeric GTP-binding proteins. As the α-subunit is ADP-ribosylated, it is permanently in an "active", GTP-bound state; subsequent activation of intracellular cyclic AMP stimulates the release of fluid and ions from intestinal epithelial cells. Furthermore, C. Botulinum C3 ADP-ribosylates GTP-binding proteins Rho and Ras, and Pertussis toxin ADP-ribosylates Gi, Go, and Gt. Diphtheria toxin ADP-ribosylates ribosomal elongation factor EF-2, which attenuates protein synthesis. There are a variety of bacteria which employ bAREs in infection: CARDS toxin of Mycoplasma pneumoniae, cholera toxin of Vibrio cholerae; heat-labile enterotoxin of E. coli; exotoxin A of Pseudomonas aeruginosa; pertussis toxin of B. pertussis; C3 toxin of C. botulinum; and diphtheria toxin of Corynebacterium diphtheriae. See also Histone code Cell signaling PARP-1 Cholera toxin NAD+ ADP-ribosyltransferase Pertussis toxin Post-translational modification References Further reading Cell biology Signal transduction Post-translational modification	ADP-ribosylation	[ "Chemistry", "Biology" ]	3,628	[ "Cell biology", "Gene expression", "Signal transduction", "Biochemical reactions", "Post-translational modification", "Biochemistry", "Neurochemistry" ]
13,222,892	https://en.wikipedia.org/wiki/IC%204703	IC 4703 is the diffuse emission nebula or HII region associated with Messier 16, which is actually a cluster of stars. It is the nebulous region surrounding Messier 16. These two objects make up the Eagle Nebula. They are relatively bright and are located in the constellation Serpens Cauda. This region contains the picturesque Pillars of Creation. This is an active star forming region 7,000 light years away. It is approximately magnitude 8. The cluster was discovered by Jean-Philippe Loys de Cheseaux, but Charles Messier later rediscovered it and remarked on its apparent nebulous appearance. The cluster is estimated to be 5.5 million years old, and the nebula would be a bit older. The nebula is about 55 x 70 light years. The Eagle Nebula lies in the Sagittarius Arm of the Milky Way. References The Belt of Venus. M16 and IC 4703 - The Eagle Nebula. 9/12/07. The Belt of Venus See also Messier 16 Eagle Nebula 4703 H II regions Carina–Sagittarius Arm Serpens	IC 4703	[ "Astronomy" ]	224	[ "Nebula stubs", "Astronomy stubs", "Constellations", "Serpens" ]
13,223,304	https://en.wikipedia.org/wiki/Robert%20Bird%20Group	Robert Bird Group (RBG), established in 1982, is an Australian global consulting engineering firm. RBG became a member of the Surbana Jurong Group in late 2017. Services Robert Bird Group provides structural engineering, civil engineering, construction engineering (temporary works), geotechnical engineering (UK & Middle East), and virtual design and construction services. Major projects Australia 400 George Street AAMI Stadium Australia108 Crown Sydney Salesforce Tower Victoria One Eq. Tower Riparian Plaza 600 Collins Street The Tower, One St George Wharf Chapel Tower The Oracle Beach Tower One Central Park 35 Spring Street United Kingdom 100 Bishopsgate Spire London The Tower, One St George Wharf 70 Gracechurch Street Elizabeth House One The Elephant Trafalgar Place Phoenix Middle East & Northern Africa ICD Brookfield Place South-East Asia Merdeka PNB118 References Engineering consulting firms of Australia International engineering consulting firms	Robert Bird Group	[ "Engineering" ]	182	[ "Engineering consulting firms", "International engineering consulting firms" ]
13,223,329	https://en.wikipedia.org/wiki/NGC%207315	NGC 7315 is a lenticular galaxy in the constellation of Pegasus. It was discovered on 11 September 1872 by Édouard Stephan. It was described as "very faint, extremely small, round, brighter middle" by John Louis Emil Dreyer, the compiler of the New General Catalogue. One supernova has been observed in NGC 7315: SN 2007B (type Ia, mag. 16.7) was discovered on 5 January 2007 by Kōichi Itagaki. See also List of NGC objects (7001–7840) References Notes External links Lenticular galaxies Pegasus (constellation) 7315 12097 069241 Astronomical objects discovered in 1872 Discoveries by Édouard Stephan	NGC 7315	[ "Astronomy" ]	138	[ "Pegasus (constellation)", "Constellations" ]
966,583	https://en.wikipedia.org/wiki/T-VIS	Toyota Variable Induction System, or T-VIS, is a variable intake system designed by Toyota to improve the low-end performance of multi-valve engines. T-VIS is intended to improve the low-end torque of high-performance, four-stroke internal combustion engines - by changing the geometry of the intake manifold according to the engine rotation speed. The system uses two separate intake runners per cylinder, one being equipped with a butterfly valve that can either open or close the runner. All valves are attached to a common shaft which is rotated by a vacuum actuator outside the manifold. T-VIS does not actually keep one of the intake valves from opening or seal off the port for one valve. The engine control unit (ECU) allows vacuum into the actuator by powering a solenoid valve when the engine rotation speed is low. At higher engine speeds (e.g. 4,200 rpm), vacuum is cut off and a spring inside the actuator causes the butterfly valve to fully open. The idea behind the system is that in the lower engine speed band, the speed of the intake air will be increased because the intake runner cross section per cylinder is smaller. However, when engine speed increases, the second runner is opened, decreasing airflow speed, but increasing the airflow volume, better matching the engine's airflow needs at higher revolutions and improving top end power. With modified engines it may be desirable to have the T-VIS open earlier than stock, because modifications that improve an engine's power output may do so by increasing airflow per engine revolution, resulting in a high airflow at a lower rpm. In addition to providing more air at higher engine speeds, the system also creates a swirl in the combustion chamber at lower rpms. The swirl makes for more efficient combustion, and is due to the asymmetric nature of the airflow with one intake runner closed. Applications: 1982.08-1990 1G-GEU/1G-GE 1983-1989 4A-GE 1986-1989 3S-GE (Both Rev 1 and Rev 2 of the 1st Generation 3S-GE) 1986-1993/95 3S-GTE (through 1995 in US market, 1993 everywhere else; 1st & 2nd generation motors only) 1997-2000 7A-FE (lean burn models only) References See also Acoustic Control Induction System Variable length intake manifold Engine technology Toyota	T-VIS	[ "Technology" ]	489	[ "Engine technology", "Engines" ]
966,640	https://en.wikipedia.org/wiki/Leafnode	Leafnode is a store-and-forward NNTP (or Usenet) proxy server designed for small sites with just a few active newsgroups, but very easy to set up and maintain, when compared to INN. Originally created by Arnt Gulbrandsen in 1995 while he was working at Trolltech, it is currently maintained by Matthias Andree and Ralf Wildenhues. The term leaf node can also be used to describe a node on a binary tree (or any other sort of tree that has nodes) which has no sub-nodes. References External links Official website Leafnode at SourceForge.org Installing and Configuring LeafNode Usenet Usenet servers	Leafnode	[ "Technology" ]	145	[ "Computing stubs", "Computer network stubs" ]
966,653	https://en.wikipedia.org/wiki/Salting%20out	Salting out (also known as salt-induced precipitation, salt fractionation, anti-solvent crystallization, precipitation crystallization, or drowning out) is a purification technique that utilizes the reduced solubility of certain molecules in a solution of very high ionic strength. Salting out is typically used to precipitate large biomolecules, such as proteins or DNA. Because the salt concentration needed for a given protein to precipitate out of the solution differs from protein to protein, a specific salt concentration can be used to precipitate a target protein. This process is also used to concentrate dilute solutions of proteins. Dialysis can be used to remove the salt if needed. Principle Salt compounds dissociate in aqueous solutions. This property is exploited in the process of salting out. When the salt concentration is increased, some of the water molecules are attracted by the salt ions, which decreases the number of water molecules available to interact with the charged part of the protein. There are hydrophobic amino acids and hydrophilic amino acids in protein molecules. After protein folding in aqueous solution, hydrophobic amino acids usually form protected hydrophobic areas while hydrophilic amino acids interact with the molecules of solvation and allow proteins to form hydrogen bonds with the surrounding water molecules. If enough of the protein surface is hydrophilic, the protein can be dissolved in water. When salt is added to the solution, there is more frequent interaction between solvent molecules and salt ions. As a result, the protein and salt ions compete to interact with the solvent molecules with the result that there are fewer solvent molecules available for interaction with the protein molecules than before. The protein–protein interactions thus become stronger than the solvent–solute interactions and the protein molecules associate by forming hydrophobic interactions with each other. After dissociation in a given solvent, the negatively charged atoms from a chosen salt begin to compete for interactions with positively charged molecules present in the solution. Similarly, the positively charged cations compete for interactions with the negatively charged molecules of the solvent. This process is known as salting out. Soaps are easily precipitated by concentrated salt solution, the metal ion in the salt reacts with the fatty acids forming back the soap and glycerin (glycerol). To separate glycerin from the soap, the pasty boiling mass is treated with brine (NaCl solution). Contents of the kettle salt out (separate) into an upper layer that is a curdy mass of impure soap and a lower layer that consists of an aqueous salt solution with the glycerin dissolved in it. The slightly alkaline salt solution, termed spent lye, is extracted from the bottom of the pan or kettle and may be subsequently treated for glycerin recovery. Application As different proteins have different compositions of amino acids, different protein molecules precipitate at different concentrations of salt solution. Unwanted proteins can be removed from a protein solution mixture by salting out as long as the solubility of the protein in various concentrations of salt solution is known. After removing the precipitate by filtration or centrifugation, the desired protein can be precipitated by altering the salt concentration to the level at which the desired protein becomes insoluble. One demerit of salting out in purification of proteins is that, in addition to precipitating a specific protein of interest, contaminants are also precipitated as well. Thus to obtain a purer protein of interest, additional purification methods such as ion exchange chromatography may be required. See also Ionic strength Protein precipitation Salting in Ammonium sulfate precipitation Hofmeister series References Further reading External links Make The Most of Antisolvent Crystallization Salting out on UC Davis ChemWiki Laboratory techniques Separation processes	Salting out	[ "Chemistry" ]	791	[ "nan", "Separation processes" ]
966,654	https://en.wikipedia.org/wiki/DNA-binding%20protein	DNA-binding proteins are proteins that have DNA-binding domains and thus have a specific or general affinity for single- or double-stranded DNA. Sequence-specific DNA-binding proteins generally interact with the major groove of B-DNA, because it exposes more functional groups that identify a base pair. Examples DNA-binding proteins include transcription factors which modulate the process of transcription, various polymerases, nucleases which cleave DNA molecules, and histones which are involved in chromosome packaging and transcription in the cell nucleus. DNA-binding proteins can incorporate such domains as the zinc finger, the helix-turn-helix, and the leucine zipper (among many others) that facilitate binding to nucleic acid. There are also more unusual examples such as transcription activator like effectors. Non-specific DNA-protein interactions Structural proteins that bind DNA are well-understood examples of non-specific DNA-protein interactions. Within chromosomes, DNA is held in complexes with structural proteins. These proteins organize the DNA into a compact structure called chromatin. In eukaryotes, this structure involves DNA binding to a complex of small basic proteins called histones. In prokaryotes, multiple types of proteins are involved. The histones form a disk-shaped complex called a nucleosome, which contains two complete turns of double-stranded DNA wrapped around its surface. These non-specific interactions are formed through basic residues in the histones making ionic bonds to the acidic sugar-phosphate backbone of the DNA, and are therefore largely independent of the base sequence. Chemical modifications of these basic amino acid residues include methylation, phosphorylation and acetylation. These chemical changes alter the strength of the interaction between the DNA and the histones, making the DNA more or less accessible to transcription factors and changing the rate of transcription. Other non-specific DNA-binding proteins in chromatin include the high-mobility group (HMG) proteins, which bind to bent or distorted DNA. Biophysical studies show that these architectural HMG proteins bind, bend and loop DNA to perform its biological functions. These proteins are important in bending arrays of nucleosomes and arranging them into the larger structures that form chromosomes. Recently FK506 binding protein 25 (FBP25) was also shown to non-specifically bind to DNA which helps in DNA repair. Proteins that specifically bind single-stranded DNA A distinct group of DNA-binding proteins are the DNA-binding proteins that specifically bind single-stranded DNA. In humans, replication protein A is the best-understood member of this family and is used in processes where the double helix is separated, including DNA replication, recombination and DNA repair. These binding proteins seem to stabilize single-stranded DNA and protect it from forming stem-loops or being degraded by nucleases. Binding to specific DNA sequences In contrast, other proteins have evolved to bind to specific DNA sequences. The most intensively studied of these are the various transcription factors, which are proteins that regulate transcription. Each transcription factor binds to one specific set of DNA sequences and activates or inhibits the transcription of genes that have these sequences near their promoters. The transcription factors do this in two ways. Firstly, they can bind the RNA polymerase responsible for transcription, either directly or through other mediator proteins; this locates the polymerase at the promoter and allows it to begin transcription. Alternatively, transcription factors can bind enzymes that modify the histones at the promoter. This alters the accessibility of the DNA template to the polymerase. These DNA targets can occur throughout an organism's genome. Thus, changes in the activity of one type of transcription factor can affect thousands of genes. Thus, these proteins are often the targets of the signal transduction processes that control responses to environmental changes or cellular differentiation and development. The specificity of these transcription factors' interactions with DNA come from the proteins making multiple contacts to the edges of the DNA bases, allowing them to read the DNA sequence. Most of these base-interactions are made in the major groove, where the bases are most accessible. Mathematical descriptions of protein-DNA binding taking into account sequence-specificity, and competitive and cooperative binding of proteins of different types are usually performed with the help of the lattice models. Computational methods to identify the DNA binding sequence specificity have been proposed to make a good use of the abundant sequence data in the post-genomic era. In addition, progress has happened on structure-based prediction of binding specificity across protein families using deep learning. Protein–DNA interactions Protein–DNA interactions occur when a protein binds a molecule of DNA, often to regulate the biological function of DNA, usually the expression of a gene. Among the proteins that bind to DNA are transcription factors that activate or repress gene expression by binding to DNA motifs and histones that form part of the structure of DNA and bind to it less specifically. Also proteins that repair DNA such as uracil-DNA glycosylase interact closely with it. In general, proteins bind to DNA in the major groove; however, there are exceptions. Protein–DNA interaction are of mainly two types, either specific interaction, or non-specific interaction. Recent single-molecule experiments showed that DNA binding proteins undergo of rapid rebinding in order to bind in correct orientation for recognizing the target site. Design Designing DNA-binding proteins that have a specified DNA-binding site has been an important goal for biotechnology. Zinc finger proteins have been designed to bind to specific DNA sequences and this is the basis of zinc finger nucleases. Recently transcription activator-like effector nucleases (TALENs) have been created which are based on natural proteins secreted by Xanthomonas bacteria via their type III secretion system when they infect various plant species. Detection methods There are many in vitro and in vivo techniques which are useful in detecting DNA-Protein Interactions. The following lists some methods currently in use: Electrophoretic mobility shift assay (EMSA) is a widespread qualitative technique to study protein–DNA interactions of known DNA binding proteins. DNA-Protein-Interaction - Enzyme-Linked ImmunoSorbant Assay (DPI-ELISA) allows the qualitative and quantitative analysis of DNA-binding preferences of known proteins in vitro. This technique allows the analysis of protein complexes that bind to DNA (DPI-Recruitment-ELISA) or is suited for automated screening of several nucleotide probes due to its standard ELISA plate formate. DNase footprinting assay can be used to identify the specific sites of binding of a protein to DNA at basepair resolution. Chromatin immunoprecipitation is used to identify the in vivo DNA target regions of a known transcription factor. This technique when combined with high throughput sequencing is known as ChIP-Seq and when combined with microarrays it is known as ChIP-chip. Yeast one-hybrid System (Y1H) is used to identify which protein binds to a particular DNA fragment. Bacterial one-hybrid system (B1H) is used to identify which protein binds to a particular DNA fragment. Structure determination using X-ray crystallography has been used to give a highly detailed atomic view of protein–DNA interactions. Besides these methods, other techniques such as SELEX, PBM (protein binding microarrays), DNA microarray screens, DamID, FAIRE or more recently DAP-seq are used in the laboratory to investigate DNA-protein interaction in vivo and in vitro. Manipulating the interactions The protein–DNA interactions can be modulated using stimuli like ionic strength of the buffer, macromolecular crowding, temperature, pH and electric field. This can lead to reversible dissociation/association of the protein–DNA complex. See also bZIP domain ChIP-exo Comparison of nucleic acid simulation software DNA-binding domain Helix-loop-helix Helix-turn-helix HMG-box Leucine zipper Lexitropsin (a semi-synthetic DNA-binding ligand) Deoxyribonucleoprotein Protein–DNA interaction site prediction software RNA-binding protein Single-strand binding protein Zinc finger References External links Protein-DNA binding: data, tools & models (annotated list, constantly updated) Abalone tool for modeling DNA-ligand interactions. DBD database of predicted transcription factors Uses a curated set of DNA-binding domains to predict transcription factors in all completely sequenced genomes DNA-binding proteins Molecular genetics DNA replication Transcription factors Biophysics	DNA-binding protein	[ "Physics", "Chemistry", "Biology" ]	1,747	[ "Genetics techniques", "Applied and interdisciplinary physics", "Gene expression", "Signal transduction", "DNA replication", "Molecular genetics", "Biophysics", "Induced stem cells", "Molecular biology", "Transcription factors" ]
966,794	https://en.wikipedia.org/wiki/Isoelectric%20focusing	Isoelectric focusing (IEF), also known as electrofocusing, is a technique for separating different molecules by differences in their isoelectric point (pI). It is a type of zone electrophoresis usually performed on proteins in a gel that takes advantage of the fact that overall charge on the molecule of interest is a function of the pH of its surroundings. Procedure IEF involves adding an ampholyte solution into immobilized pH gradient (IPG) gels. IPGs are the acrylamide gel matrix co-polymerized with the pH gradient, which result in completely stable gradients except the most alkaline (>12) pH values. The immobilized pH gradient is obtained by the continuous change in the ratio of immobilines. An immobiline is a weak acid or base defined by its pK value. A protein that is in a pH region below its isoelectric point (pI) will be positively charged and so will migrate toward the cathode (negatively charged electrode). As it migrates through a gradient of increasing pH, however, the protein's overall charge will decrease until the protein reaches the pH region that corresponds to its pI. At this point it has no net charge and so migration ceases (as there is no electrical attraction toward either electrode). As a result, the proteins become focused into sharp stationary bands with each protein positioned at a point in the pH gradient corresponding to its pI. The technique is capable of extremely high resolution with proteins differing by a single charge being fractionated into separate bands. Molecules to be focused are distributed over a medium that has a pH gradient (usually created by aliphatic ampholytes). An electric current is passed through the medium, creating a "positive" anode and "negative" cathode end. Negatively charged molecules migrate through the pH gradient in the medium toward the "positive" end while positively charged molecules move toward the "negative" end. As a particle moves toward the pole opposite of its charge it moves through the changing pH gradient until it reaches a point in which the pH of that molecule's isoelectric point is reached. At this point the molecule no longer has a net electric charge (due to the protonation or deprotonation of the associated functional groups) and as such will not proceed any further within the gel. The gradient is established before adding the particles of interest by first subjecting a solution of small molecules such as polyampholytes with varying pI values to electrophoresis. The method is applied particularly often in the study of proteins, which separate based on their relative content of acidic and basic residues, whose value is represented by the pI. Proteins are introduced into an immobilized pH gradient gel composed of polyacrylamide, starch, or agarose where a pH gradient has been established. Gels with large pores are usually used in this process to eliminate any "sieving" effects, or artifacts in the pI caused by differing migration rates for proteins of differing sizes. Isoelectric focusing can resolve proteins that differ in pI value by as little as 0.01. Isoelectric focusing is the first step in two-dimensional gel electrophoresis, in which proteins are first separated by their pI value and then further separated by molecular weight through SDS-PAGE. Isoelectric focusing, on the other hand, is the only step in preparative native PAGE at constant pH. Living cells According to some opinions, living eukaryotic cells perform isoelectric focusing of proteins in their interior to overcome a limitation of the rate of metabolic reaction by diffusion of enzymes and their reactants, and to regulate the rate of particular biochemical processes. By concentrating the enzymes of particular metabolic pathways into distinct and small regions of its interior, the cell can increase the rate of particular biochemical pathways by several orders of magnitude. By modification of the isoelectric point (pI) of molecules of an enzyme by, e.g., phosphorylation or dephosphorylation, the cell can transfer molecules of the enzyme between different parts of its interior, to switch on or switch off particular biochemical processes. Microfluidic chip based Microchip based electrophoresis is a promising alternative to capillary electrophoresis since it has the potential to provide rapid protein analysis, straightforward integration with other microfluidic unit operations, whole channel detection, nitrocellulose films, smaller sample sizes and lower fabrication costs. Multi-junction The increased demand for faster and easy-to-use protein separation tools has accelerated the evolution of IEF towards in-solution separations. In this context, a multi-junction IEF system was developed to perform fast and gel-free IEF separations. The multi-junction IEF system utilizes a series of vessels with a capillary passing through each vessel. Part of the capillary in each vessel is replaced by a semipermeable membrane. The vessels contain buffer solutions with different pH values, so that a pH gradient is effectively established inside the capillary. The buffer solution in each vessel has an electrical contact with a voltage divider connected to a high-voltage power supply, which establishes an electrical field along the capillary. When a sample (a mixture of peptides or proteins) is injected in the capillary, the presence of the electrical field and the pH gradient separates these molecules according to their isoelectric points. The multi-junction IEF system has been used to separate tryptic peptide mixtures for two-dimensional proteomics and blood plasma proteins from Alzheimer's disease patients for biomarker discovery. References Electrophoresis Industrial processes Protein methods Molecular biology techniques	Isoelectric focusing	[ "Chemistry", "Biology" ]	1,180	[ "Biochemistry methods", "Instrumental analysis", "Protein methods", "Protein biochemistry", "Biochemical separation processes", "Molecular biology techniques", "Molecular biology", "Electrophoresis" ]
966,847	https://en.wikipedia.org/wiki/Mayall%20II	Mayall II, also known as NGC-224-G1, SKHB 1, GSC 2788:2139, HBK 0-1, M31GC J003247+393440 or Andromeda's Cluster, is a globular cluster orbiting M31, the Andromeda Galaxy. It is located from the Andromeda Galaxy's galactic core, and is the brightest (by absolute magnitude) globular cluster in the Local Group, with an absolute visual magnitude of −10.94 and the luminosity of 2 million Suns. It has an apparent magnitude of 13.81 in V band. Mayall II is considered to have twice the mass of Omega Centauri, and may contain a central, intermediate-mass (~ 2 M⊙) black hole. It was first identified as a possible globular cluster by American astronomers Nicholas Mayall and Olin J. Eggen in 1953 using a Palomar Schmidt plate exposed in 1948. Because of the widespread distribution of metallicity, indicating multiple star generations and a large stellar creation period, many contend that it is not a true globular cluster, but is actually the galactic core that remains of a dwarf galaxy consumed by Andromeda. Origin of names Mayall II is named after Nicholas U. Mayall, who, with Olin J. Eggen, discovered it in 1953. SKHB 1 is named for Wallace L. W. Sargent, Charles T. Kowal, F. D. A. Hartwick and Sidney van den Bergh. They also named it G1 in 1977. HBK 0-1 is named for John Huchra, J. P. Brodie and S. M. Kent in 1991. See also Messier 54 Omega Centauri Mayall's Object References External links Astrophysical Journal, Vol. 370, p. 495–504 Publications of the Astronomical Society of the Pacific, Vol. 65, No. 382, p. 24–29 Astronomical Journal, vol. 82, p. 947–953 NightSkyInfo.com: Mayall II Andromeda Galaxy Globular clusters Andromeda (constellation)	Mayall II	[ "Astronomy" ]	450	[ "Andromeda (constellation)", "Constellations" ]
966,856	https://en.wikipedia.org/wiki/Valuation%20ring	In abstract algebra, a valuation ring is an integral domain D such that for every non-zero element x of its field of fractions F, at least one of x or x−1 belongs to D. Given a field F, if D is a subring of F such that either x or x−1 belongs to D for every nonzero x in F, then D is said to be a valuation ring for the field F or a place of F. Since F in this case is indeed the field of fractions of D, a valuation ring for a field is a valuation ring. Another way to characterize the valuation rings of a field F is that valuation rings D of F have F as their field of fractions, and their ideals are totally ordered by inclusion; or equivalently their principal ideals are totally ordered by inclusion. In particular, every valuation ring is a local ring. The valuation rings of a field are the maximal elements of the set of the local subrings in the field partially ordered by dominance or refinement, where dominates if and . Every local ring in a field K is dominated by some valuation ring of K. An integral domain whose localization at any prime ideal is a valuation ring is called a Prüfer domain. Definitions There are several equivalent definitions of valuation ring (see below for the characterization in terms of dominance). For an integral domain D and its field of fractions K, the following are equivalent: For every non-zero x in K, at least one of x or x−1 is in D. The ideals of D are totally ordered by inclusion. The principal ideals of D are totally ordered by inclusion (i.e. the elements in D are, up to units, totally ordered by divisibility.) There is a totally ordered abelian group Γ (called the value group) and a valuation ν: K → Γ ∪ {∞} with D = { x ∈ K \| ν(x) ≥ 0 }. The equivalence of the first three definitions follows easily. A theorem of states that any ring satisfying the first three conditions satisfies the fourth: take Γ to be the quotient K×/D× of the unit group of K by the unit group of D, and take ν to be the natural projection. We can turn Γ into a totally ordered group by declaring the residue classes of elements of D as "positive". Even further, given any totally ordered abelian group Γ, there is a valuation ring D with value group Γ (see Hahn series). From the fact that the ideals of a valuation ring are totally ordered, one can conclude that a valuation ring is a local domain, and that every finitely generated ideal of a valuation ring is principal (i.e., a valuation ring is a Bézout domain). In fact, it is a theorem of Krull that an integral domain is a valuation ring if and only if it is a local Bézout domain. It also follows from this that a valuation ring is Noetherian if and only if it is a principal ideal domain. In this case, it is either a field or it has exactly one non-zero prime ideal; in the latter case it is called a discrete valuation ring. (By convention, a field is not a discrete valuation ring.) A value group is called discrete if it is isomorphic to the additive group of the integers, and a valuation ring has a discrete valuation group if and only if it is a discrete valuation ring. Very rarely, valuation ring may refer to a ring that satisfies the second or third condition but is not necessarily a domain. A more common term for this type of ring is uniserial ring. Examples Any field is a valuation ring. For example, the field of rational functions on an algebraic variety . A simple non-example is the integral domain since the inverse of a generic is . The field of power series: has the valuation . The subring is a valuation ring as well. the localization of the integers at the prime ideal (p), consisting of ratios where the numerator is any integer and the denominator is not divisible by p. The field of fractions is the field of rational numbers The ring of meromorphic functions on the entire complex plane which have a Maclaurin series (Taylor series expansion at zero) is a valuation ring. The field of fractions are the functions meromorphic on the whole plane. If f does not have a Maclaurin series then 1/f does. Any ring of p-adic integers for a given prime p is a local ring, with field of fractions the p-adic numbers . The integral closure of the p-adic integers is also a local ring, with field of fractions (the algebraic closure of the p-adic numbers). Both and are valuation rings. Let k be an ordered field. An element of k is called finite if it lies between two integers n < x < m; otherwise it is called infinite. The set D of finite elements of k is a valuation ring. The set of elements x such that x ∈ D and x−1 ∉ D is the set of infinitesimal elements; and an element x such that x ∉ D and x−1 ∈ D is called infinite. The ring F of finite elements of a hyperreal field R (an ordered field containing the real numbers) is a valuation ring of R. F consists of all hyperreal numbers differing from a standard real by an infinitesimal amount, which is equivalent to saying a hyperreal number x such that −n < x < n for some standard integer n. The residue field, finite hyperreal numbers modulo the ideal of infinitesimal hyperreal numbers, is isomorphic to the real numbers. A common geometric example comes from algebraic plane curves. Consider the polynomial ring and an irreducible polynomial in that ring. Then the ring is the ring of polynomial functions on the curve . Choose a point such that and it is a regular point on the curve; i.e., the local ring R at the point is a regular local ring of Krull dimension one or a discrete valuation ring. For example, consider the inclusion . These are all subrings in the field of bounded-below power series . Dominance and integral closure The units, or invertible elements, of a valuation ring are the elements x in D such that x −1 is also a member of D. The other elements of D – called nonunits – do not have an inverse in D, and they form an ideal M. This ideal is maximal among the (totally ordered) ideals of D. Since M is a maximal ideal, the quotient ring D/M is a field, called the residue field of D. In general, we say a local ring dominates a local ring if and ; in other words, the inclusion is a local ring homomorphism. Every local ring in a field K is dominated by some valuation ring of K. Indeed, the set consisting of all subrings R of K containing A and is nonempty and is inductive; thus, has a maximal element by Zorn's lemma. We claim R is a valuation ring. R is a local ring with maximal ideal containing by maximality. Again by maximality it is also integrally closed. Now, if , then, by maximality, and thus we can write: . Since is a unit element, this implies that is integral over R; thus is in R. This proves R is a valuation ring. (R dominates A since its maximal ideal contains by construction.) A local ring R in a field K is a valuation ring if and only if it is a maximal element of the set of all local rings contained in K partially ordered by dominance. This easily follows from the above. Let A be a subring of a field K and a ring homomorphism into an algebraically closed field k. Then f extends to a ring homomorphism , D some valuation ring of K containing A. (Proof: Let be a maximal extension, which clearly exists by Zorn's lemma. By maximality, R is a local ring with maximal ideal containing the kernel of f. If S is a local ring dominating R, then S is algebraic over R; if not, contains a polynomial ring to which g extends, a contradiction to maximality. It follows is an algebraic field extension of . Thus, extends g; hence, S = R.) If a subring R of a field K contains a valuation ring D of K, then, by checking Definition 1, R is also a valuation ring of K. In particular, R is local and its maximal ideal contracts to some prime ideal of D, say, . Then since dominates , which is a valuation ring since the ideals are totally ordered. This observation is subsumed to the following: there is a bijective correspondence the set of all subrings of K containing D. In particular, D is integrally closed, and the Krull dimension of D is the number of proper subrings of K containing D. In fact, the integral closure of an integral domain A in the field of fractions K of A is the intersection of all valuation rings of K containing A. Indeed, the integral closure is contained in the intersection since the valuation rings are integrally closed. Conversely, let x be in K but not integral over A. Since the ideal is not , it is contained in a maximal ideal . Then there is a valuation ring R that dominates the localization of at . Since , . The dominance is used in algebraic geometry. Let X be an algebraic variety over a field k. Then we say a valuation ring R in has "center x on X" if dominates the local ring of the structure sheaf at x. Ideals in valuation rings We may describe the ideals in the valuation ring by means of its value group. Let Γ be a totally ordered abelian group. A subset Δ of Γ is called a segment if it is nonempty and, for any α in Δ, any element between −α and α is also in Δ (end points included). A subgroup of Γ is called an isolated subgroup if it is a segment and is a proper subgroup. Let D be a valuation ring with valuation v and value group Γ. For any subset A of D, we let be the complement of the union of and in . If I is a proper ideal, then is a segment of . In fact, the mapping defines an inclusion-reversing bijection between the set of proper ideals of D and the set of segments of . Under this correspondence, the nonzero prime ideals of D correspond bijectively to the isolated subgroups of Γ. Example: The ring of p-adic integers is a valuation ring with value group . The zero subgroup of corresponds to the unique maximal ideal and the whole group to the zero ideal. The maximal ideal is the only isolated subgroup of . The set of isolated subgroups is totally ordered by inclusion. The height or rank r(Γ) of Γ is defined to be the cardinality of the set of isolated subgroups of Γ. Since the nonzero prime ideals are totally ordered and they correspond to isolated subgroups of Γ, the height of Γ is equal to the Krull dimension of the valuation ring D associated with Γ. The most important special case is height one, which is equivalent to Γ being a subgroup of the real numbers under addition (or equivalently, of the positive real numbers under multiplication.) A valuation ring with a valuation of height one has a corresponding absolute value defining an ultrametric place. A special case of this are the discrete valuation rings mentioned earlier. The rational rank rr(Γ) is defined as the rank of the value group as an abelian group, Places General definition A place of a field K is a ring homomorphism p from a valuation ring D of K to some field such that, for any , . The image of a place is a field called the residue field of p. For example, the canonical map is a place. Example Let A be a Dedekind domain and a prime ideal. Then the canonical map is a place. Specialization of places We say a place p specializes to a place , denoted by , if the valuation ring of p contains the valuation ring of p. In algebraic geometry, we say a prime ideal specializes to if . The two notions coincide: if and only if a prime ideal corresponding to p specializes to a prime ideal corresponding to in some valuation ring (recall that if are valuation rings of the same field, then D corresponds to a prime ideal of .) Example For example, in the function field of some algebraic variety every prime ideal contained in a maximal ideal gives a specialization . Remarks It can be shown: if , then for some place q of the residue field of p. (Observe is a valuation ring of and let q be the corresponding place; the rest is mechanical.) If D is a valuation ring of p, then its Krull dimension is the cardinarity of the specializations other than p to p. Thus, for any place p with valuation ring D of a field K over a field k, we have: . If p is a place and A is a subring of the valuation ring of p, then is called the center of p in A. Places at infinity For the function field on an affine variety there are valuations which are not associated to any of the primes of . These valuations are called the places at infinity. For example, the affine line has function field . The place associated to the localization of at the maximal ideal is a place at infinity. Notes Citations Sources Commutative algebra Field (mathematics) Localization (mathematics) Ring theory	Valuation ring	[ "Mathematics" ]	2,814	[ "Fields of abstract algebra", "Commutative algebra", "Ring theory" ]
966,859	https://en.wikipedia.org/wiki/Total%20Ozone%20Mapping%20Spectrometer	The Total Ozone Mapping Spectrometer (TOMS) was a NASA satellite instrument, specifically a spectrometer, for measuring the ozone layer. Of the five TOMS instruments which were built, four entered successful orbit. The satellites carrying TOMS instruments were: Nimbus 7; launched October 24, 1978. Operated until 1 August 1994. Carried TOMS instrument number 1. Meteor-3-5; launched 15 August 1991. Operated until December 1994. Was the first and last Soviet satellite to carry a USA made instrument. Carried TOMS instrument number 2. ADEOS I; launched 17 August 1996. Operated until 30 June 1997. Mission was cut short by a spacecraft failure. TOMS-Earth Probe; launched on July 2, 1996. Operated until 2 December 2006. Carried TOMS instrument number 3. QuikTOMS; launched 21 September 2001. Suffered launch failure and did not enter orbit. Nimbus 7 and Meteor-3-5 provided global measurements of total column ozone on a daily basis and together provided a complete data set of daily ozone from November 1978 to December 1994. After an eighteen-month period when the program had no on-orbit capability, TOMS-Earth Probe launched on 2 July 1996, followed by . ADEOS I was launched on August 17, 1996, and the TOMS-instrument onboard provided data until the satellite which housed it lost power on June 30, 1997. TOMS-Earth Probe (Total Ozone Mapping Spectrometer - Earth Probe, TOMS-EP, originally just TOMS, COSPAR 1996-037A) was launched on July 2, 1996, from Vandenberg AFB by a Pegasus XL rocket. The satellite project was originally known as TOMS, back in 1989 when it was selected as a SMEX mission in the Explorer program. However, it found no funding as an Explorer mission and transferred to NASA's Earth Probe program, getting funding and becoming TOMS-EP. The small, 295 kg satellite was built for NASA by TRW; the single instrument was the TOMS 3 spectrometer. The satellite had a two-year planned life. TOMS-EP suffered a two-year delay to its launch due to launch failures of the first two Pegasus XL rockets. The launch delays led to alternations in the mission; the satellite was placed in a lower than originally planned orbit to achieve higher resolution and to enable more thorough study of UV-absorbing aerosols in the troposphere. The lower orbit was meant to complement measurements from ADEOS I enabling TOMS-EP to provide supplemental measurements. After ADEOS I failed in orbit, TOMS-EP was boosted to a higher orbit to replace ADEOS I. The transmitter for TOMS-Earth Probe failed on December 2, 2006. The only total failure in the series was QuikTOMS, which was launched on September 21, 2001, on a Taurus rocket from Vandenberg AFB, but did not achieve orbit. Since January 1, 2006, data from the Aura Ozone Monitoring Instrument (OMI) has replaced data from TOMS-Earth Probe. The Ozone Mapping and Profiler Suite on Suomi NPP and NOAA-20 have further continued the data record. Gallery References External links TOMS home page TOMS Volcanic Emissions Group Further reading Scientific instruments Satellite meteorology Spacecraft instruments Spectrometers Ozone depletion Earth observation satellite sensors	Total Ozone Mapping Spectrometer	[ "Physics", "Chemistry", "Technology", "Engineering" ]	690	[ "Spectrum (physical sciences)", "Scientific instruments", "Measuring instruments", "Spectrometers", "Spectroscopy" ]

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