title: Unicode

text: The Consortium has the ambitious goal of eventually replacing existing character encoding schemes with Unicode and its standard Unicode Transformation Format (UTF) schemes, as many of the existing schemes are limited in size and scope and are incompatible with multilingual environments.


title: Unicode

text: , a total of 161 scripts are included in the latest version of Unicode (covering alphabets, abugidas and syllabaries), although there are still scripts that are not yet encoded, particularly those mainly used in historical, liturgical, and academic contexts. Further additions of characters to the already encoded scripts, as well as symbols, in particular for mathematics and music (in the form of notes and rhythmic symbols), also occur.


title: Unicode

text: The Unicode Roadmap Committee (Michael Everson, Rick McGowan, Ken Whistler, V.S. Umamaheswaran) maintain the list of scripts that are candidates or potential candidates for encoding and their tentative code block assignments on the Unicode Roadmap page of the Unicode Consortium website. For some scripts on the Roadmap, such as Jurchen and Khitan small script, encoding proposals have been made and they are working their way through the approval process. For other scripts, such as Mayan (besides numbers) and Rongorongo, no proposal has yet been made, and they await agreement on character repertoire and other details from the user communities involved.


title: Unicode

text: Some modern invented scripts which have not yet been included in Unicode (e.g., Tengwar) or which do not qualify for inclusion in Unicode due to lack of real-world use (e.g., Klingon) are listed in the ConScript Unicode Registry, along with unofficial but widely used Private Use Areas code assignments.


title: Unicode

text: There is also a Medieval Unicode Font Initiative focused on special Latin medieval characters. Part of these proposals have been already included into Unicode.


title: Unicode

text: The Script Encoding Initiative, a project run by Deborah Anderson at the University of California, Berkeley was founded in 2002 with the goal of funding proposals for scripts not yet encoded in the standard. The project has become a major source of proposed additions to the standard in recent years.


title: Unicode

text: The Unicode Consortium and the International Organization for Standardization (ISO) have together developed a shared repertoire following the initial publication of "The Unicode Standard" in 1991; Unicode and the ISO's Universal Coded Character Set (UCS) use identical character names and code points. However, the Unicode versions do differ from their ISO equivalents in two significant ways.


title: Unicode

text: While the UCS is a simple character map, Unicode specifies the rules, algorithms, and properties necessary to achieve interoperability between different platforms and languages. Thus, "The Unicode Standard" includes more information, covering—in depth—topics such as bitwise encoding, collation and rendering. It also provides a comprehensive catalog of character properties, including those needed for supporting bidirectional text, as well as visual charts and reference data sets to aid implementers. Previously, "The Unicode Standard" was sold as a print volume containing the complete core specification, standard annexes, and code charts. However, Unicode 5.0, published in 2006, was the last version printed this way. Starting with version 5.2, only the core specification, published as print-on-demand paperback, may be purchased. The full text, on the other hand, is published as a free PDF on the Unicode website.


title: Unicode

text: A practical reason for this publication method highlights the second significant difference between the UCS and Unicode—the frequency with which updated versions are released and new characters added. "The Unicode Standard" has regularly released annual expanded versions, occasionally with more than one version released in a calendar year and with rare cases where the scheduled release had to be postponed. For instance, in April 2020, only a month after version 13.0 was published, the Unicode Consortium announced they had changed the intended release date for version 14.0, pushing it back six months from March 2021 to September 2021 due to the COVID-19 pandemic.


title: Unicode

text: The latest version of Unicode, 15.0.0, was released on 13 September 2022. Several annexes were updated including Unicode Security Mechanisms (UTS #39), and a total of 4489 new characters were encoded, including 20 new emoji characters, such as "wireless" (network) symbol and hearts in different colors such as pink, two new scripts, CJK Unified Ideographs extension, and multiple additions to existing blocks.


title: Unicode

text: Thus far, the following major and minor versions of the Unicode standard have been published. Update versions, which do not include any changes to character repertoire, are signified by the third number (e.g., "version 4.0.1") and are omitted in the table below.


title: Unicode

text: The Unicode Standard defines a "codespace," a set of numerical values ranging from 0 through 10FFFF, called "code points" and denoted as through ("U+" followed by the code point value in hexadecimal, which is prepended with leading zeros to a minimum of four digits; "e. g.", for the division sign but ("not" ) for the Egyptian hieroglyph .). Of these 2 + 2 defined code points, the code points from through , which are used to encode surrogate pairs in UTF-16, are reserved by the Unicode Standard and may not be used to encode valid characters, resulting in a net total of 2 − 2 + 2 = 1,112,064 assignable code points.


title: Unicode

text: The Unicode codespace is divided into seventeen "planes", numbered 0 to 16. Plane 0 is the Basic Multilingual Plane (BMP), which contains most commonly used characters. All code points in the BMP are accessed as a single code unit in UTF-16 encoding and can be encoded in one, two or three bytes in UTF-8. Code points in Planes 1 through 16 ("supplementary planes") are accessed as surrogate pairs in UTF-16 and encoded in four bytes in UTF-8.


title: Unicode

text: Within each plane, characters are allocated within named "blocks" of related characters. Although blocks are an arbitrary size, they are always a multiple of 16 code points and often a multiple of 128 code points. Characters required for a given script may be spread out over several different blocks.


title: Unicode

text: Each code point has a single General Category property. The major categories are denoted: Letter, Mark, Number, Punctuation, Symbol, Separator and Other. Within these categories, there are subdivisions. In most cases other properties must be used to sufficiently specify the characteristics of a code point. The possible General Categories are:


title: Unicode

text: Code points in the range U+D800–U+DBFF (1,024 code points) are known as high-surrogate code points, and code points in the range U+DC00–U+DFFF (1,024 code points) are known as low-surrogate code points. A high-surrogate code point followed by a low-surrogate code point form a surrogate pair in UTF-16 to represent code points greater than U+FFFF. These code points otherwise cannot be used (this rule is ignored often in practice especially when not using UTF-16).


title: Unicode

text: A small set of code points are guaranteed never to be used for encoding characters, although applications may make use of these code points internally if they wish. There are sixty-six of these noncharacters: U+FDD0–U+FDEF and any code point ending in the value FFFE or FFFF (i.e., U+FFFE, U+FFFF, U+1FFFE, U+1FFFF, ... U+10FFFE, U+10FFFF). The set of noncharacters is stable, and no new noncharacters will ever be defined. Like surrogates, the rule that these cannot be used is often ignored, although the operation of the byte order mark (BOM) assumes that U+FFFE will never be the first code point in a text.


title: Unicode

text: Private-use code points are considered to be assigned characters, but they have no interpretation specified by the Unicode standard so any interchange of such characters requires an agreement between sender and receiver on their interpretation. There are three private-use areas in the Unicode codespace:


title: Unicode

text: Graphic characters are characters defined by Unicode to have particular semantics, and either have a visible glyph shape or represent a visible space. As of Unicode 15.0 there are 149,014 graphic characters.


title: Unicode

text: Format characters are characters that do not have a visible appearance, but may have an effect on the appearance or behavior of neighboring characters. For example, and may be used to change the default shaping behavior of adjacent characters (e.g., to inhibit ligatures or request ligature formation). There are 172 format characters in Unicode 15.0.


title: Unicode

text: Sixty-five code points (U+0000–U+001F and U+007F–U+009F) are reserved as control codes, and correspond to the C0 and C1 control codes defined in ISO/IEC 6429. U+0009 (Tab), U+000A (Line Feed), and U+000D (Carriage Return) are widely used in Unicode-encoded texts. In practice the C1 code points are often improperly-translated (mojibake) as the legacy Windows-1252 characters used by some English and Western European texts.


title: Unicode

text: Graphic characters, format characters, control code characters, and private use characters are known collectively as "assigned characters". Reserved code points are those code points which are available for use, but are not yet assigned. As of Unicode 15.0 there are 825,279 reserved code points.


title: Unicode

text: The set of graphic and format characters defined by Unicode does not correspond directly to the repertoire of "abstract characters" that is representable under Unicode. Unicode encodes characters by associating an abstract character with a particular code point. However, not all abstract characters are encoded as a single Unicode character, and some abstract characters may be represented in Unicode by a sequence of two or more characters. For example, a Latin small letter "i" with an ogonek, a dot above, and an acute accent, which is required in Lithuanian, is represented by the character sequence U+012F, U+0307, U+0301. Unicode maintains a list of uniquely named character sequences for abstract characters that are not directly encoded in Unicode.


title: Unicode

text: All graphic, format, and private use characters have a unique and immutable name by which they may be identified. This immutability has been guaranteed since Unicode version 2.0 by the Name Stability policy. In cases where the name is seriously defective and misleading, or has a serious typographical error, a formal alias may be defined, and applications are encouraged to use the formal alias in place of the official character name. For example, has the formal alias , and has the formal alias .


title: Unicode

text: Unicode includes a mechanism for modifying characters that greatly extends the supported glyph repertoire. This covers the use of combining diacritical marks that may be added after the base character by the user. Multiple combining diacritics may be simultaneously applied to the same character. Unicode also contains precomposed versions of most letter/diacritic combinations in normal use. These make conversion to and from legacy encodings simpler, and allow applications to use Unicode as an internal text format without having to implement combining characters. For example, "é" can be represented in Unicode as U+0065 () followed by U+0301 (), but it can also be represented as the precomposed character U+00E9 (). Thus, in many cases, users have multiple ways of encoding the same character. To deal with this, Unicode provides the mechanism of canonical equivalence.


title: Unicode

text: An example of this arises with Hangul, the Korean alphabet. Unicode provides a mechanism for composing Hangul syllables with their individual subcomponents, known as Hangul Jamo. However, it also provides 11,172 combinations of precomposed syllables made from the most common jamo.


title: Unicode

text: The CJK characters currently have codes only for their precomposed form. Still, most of those characters comprise simpler elements (called radicals), so in principle Unicode could have decomposed them as it did with Hangul. This would have greatly reduced the number of required code points, while allowing the display of virtually every conceivable character (which might do away with some of the problems caused by Han unification). A similar idea is used by some input methods, such as Cangjie and Wubi. However, attempts to do this for character encoding have stumbled over the fact that Chinese characters do not decompose as simply or as regularly as Hangul does.


title: Unicode

text: A set of radicals was provided in Unicode 3.0 (CJK radicals between U+2E80 and U+2EFF, KangXi radicals in U+2F00 to U+2FDF, and ideographic description characters from U+2FF0 to U+2FFB), but the Unicode standard (ch. 12.2 of Unicode 5.2) warns against using ideographic description sequences as an alternate representation for previously encoded characters:


title: Unicode

text: Many scripts, including Arabic and Devanāgarī, have special orthographic rules that require certain combinations of letterforms to be combined into special ligature forms. The rules governing ligature formation can be quite complex, requiring special script-shaping technologies such as ACE (Arabic Calligraphic Engine by DecoType in the 1980s and used to generate all the Arabic examples in the printed editions of the Unicode Standard), which became the proof of concept for OpenType (by Adobe and Microsoft), Graphite (by SIL International), or AAT (by Apple).


title: Unicode

text: Instructions are also embedded in fonts to tell the operating system how to properly output different character sequences. A simple solution to the placement of combining marks or diacritics is assigning the marks a width of zero and placing the glyph itself to the left or right of the left sidebearing (depending on the direction of the script they are intended to be used with). A mark handled this way will appear over whatever character precedes it, but will not adjust its position relative to the width or height of the base glyph; it may be visually awkward and it may overlap some glyphs. Real stacking is impossible, but can be approximated in limited cases (for example, Thai top-combining vowels and tone marks can just be at different heights to start with). Generally this approach is only effective in monospaced fonts, but may be used as a fallback rendering method when more complex methods fail.


title: Unicode

text: Several subsets of Unicode are standardized: Microsoft Windows since Windows NT 4.0 supports WGL-4 with 657 characters, which is considered to support all contemporary European languages using the Latin, Greek, or Cyrillic script. Other standardized subsets of Unicode include the Multilingual European Subsets: MES-1 (Latin scripts only, 335 characters), MES-2 (Latin, Greek and Cyrillic 1062 characters) and MES-3A & MES-3B (two larger subsets, not shown here). Note that MES-2 includes every character in MES-1 and WGL-4.


title: Unicode

text: The standard DIN 91379 specifies a subset of Unicode letters, special characters, and sequences of letters and diacritic signs to allow the correct representation of names and to simplify data exchange in Europe. This specification supports all official languages of European Union countries as well as the official languages of Iceland, Liechtenstein, Norway, and Switzerland, and also the German minority languages. To allow the transliteration of names in other writing systems to the Latin script according to the relevant ISO standards all necessary combinations of base letters and diacritic signs are provided.


title: Unicode

text: Rendering software which cannot process a Unicode character appropriately often displays it as an open rectangle, or the Unicode "replacement character" (U+FFFD, �), to indicate the position of the unrecognized character. Some systems have made attempts to provide more information about such characters. Apple's Last Resort font will display a substitute glyph indicating the Unicode range of the character, and the SIL International's Unicode Fallback font will display a box showing the hexadecimal scalar value of the character.


title: Unicode

text: Unicode defines two mapping methods: the Unicode Transformation Format (UTF) encodings, and the Universal Coded Character Set (UCS) encodings. An encoding maps (possibly a subset of) the range of Unicode "code points" to sequences of values in some fixed-size range, termed "code units". All UTF encodings map code points to a unique sequence of bytes. The numbers in the names of the encodings indicate the number of bits per code unit (for UTF encodings) or the number of bytes per code unit (for UCS encodings and UTF-1). UTF-8 and UTF-16 are the most commonly used encodings. UCS-2 is an obsolete subset of UTF-16; UCS-4 and UTF-32 are functionally equivalent.


title: Unicode

text: UTF-8 uses one to four bytes per code point and, being compact for Latin scripts and ASCII-compatible, provides the "de facto" standard encoding for interchange of Unicode text. It is used by FreeBSD and most recent Linux distributions as a direct replacement for legacy encodings in general text handling.


title: Unicode

text: The UCS-2 and UTF-16 encodings specify the Unicode byte order mark (BOM) for use at the beginnings of text files, which may be used for byte-order detection (or byte endianness detection). The BOM, code point U+FEFF, has the important property of unambiguity on byte reorder, regardless of the Unicode encoding used; U+FFFE (the result of byte-swapping U+FEFF) does not equate to a legal character, and U+FEFF in places other than the beginning of text conveys the zero-width non-break space (a character with no appearance and no effect other than preventing the formation of ligatures).


title: Unicode

text: The same character converted to UTF-8 becomes the byte sequence codice_1. The Unicode Standard allows that the BOM "can serve as signature for UTF-8 encoded text where the character set is unmarked". Some software developers have adopted it for other encodings, including UTF-8, in an attempt to distinguish UTF-8 from local 8-bit code pages. However , the UTF-8 standard, recommends that byte order marks be forbidden in protocols using UTF-8, but discusses the cases where this may not be possible. In addition, the large restriction on possible patterns in UTF-8 (for instance there cannot be any lone bytes with the high bit set) means that it should be possible to distinguish UTF-8 from other character encodings without relying on the BOM.


title: Unicode

text: In UTF-32 and UCS-4, one 32-bit code unit serves as a fairly direct representation of any character's code point (although the endianness, which varies across different platforms, affects how the code unit manifests as a byte sequence). In the other encodings, each code point may be represented by a variable number of code units. UTF-32 is widely used as an internal representation of text in programs (as opposed to stored or transmitted text), since every Unix operating system that uses the gcc compilers to generate software uses it as the standard "wide character" encoding. Some programming languages, such as Seed7, use UTF-32 as internal representation for strings and characters. Recent versions of the Python programming language (beginning with 2.2) may also be configured to use UTF-32 as the representation for Unicode strings, effectively disseminating such encoding in high-level coded software.


title: Unicode

text: Punycode, another encoding form, enables the encoding of Unicode strings into the limited character set supported by the ASCII-based Domain Name System (DNS). The encoding is used as part of IDNA, which is a system enabling the use of Internationalized Domain Names in all scripts that are supported by Unicode. Earlier and now historical proposals include UTF-5 and UTF-6.


title: Unicode

text: GB18030 is another encoding form for Unicode, from the Standardization Administration of China. It is the official character set of the People's Republic of China (PRC). BOCU-1 and SCSU are Unicode compression schemes. The April Fools' Day RFC of 2005 specified two parody UTF encodings, UTF-9 and UTF-18.


title: Unicode

text: Unicode, in the form of UTF-8, has been the most common encoding for the World Wide Web since 2008. It has near-universal adoption, and much of the non-UTF-8 content is found in other Unicode encodings, e.g. UTF-16. , UTF-8 accounts for on average 97.8% of all web pages (and 988 of the top 1,000 highest ranked web pages). Although many pages only use ASCII characters to display content, UTF-8 was designed with 8-bit ASCII as a subset and almost no websites now declare their encoding to only be ASCII instead of UTF-8. Over a third of the languages tracked have 100% UTF-8 use.


title: Unicode

text: All internet protocols maintained by Internet Engineering Task Force, e.g. FTP, have required support for UTF-8 since the publication of in 1998, which specified that all IETF protocols "MUST be able to use the UTF-8 charset".


title: Unicode

text: Unicode has become the dominant scheme for internal processing and storage of text. Although a great deal of text is still stored in legacy encodings, Unicode is used almost exclusively for building new information processing systems. Early adopters tended to use UCS-2 (the fixed-length two-byte obsolete precursor to UTF-16) and later moved to UTF-16 (the variable-length current standard), as this was the least disruptive way to add support for non-BMP characters. The best known such system is Windows NT (and its descendants, 2000, XP, Vista, 7, 8, 10, and 11), which uses UTF-16 as the sole internal character encoding. The Java and .NET bytecode environments, macOS, and KDE also use it for internal representation. Partial support for Unicode can be installed on Windows 9x through the Microsoft Layer for Unicode.


title: Unicode

text: UTF-8 (originally developed for Plan 9) has become the main storage encoding on most Unix-like operating systems (though others are also used by some libraries) because it is a relatively easy replacement for traditional extended ASCII character sets. UTF-8 is also the most common Unicode encoding used in HTML documents on the World Wide Web.


title: Unicode

text: Multilingual text-rendering engines which use Unicode include Uniscribe and DirectWrite for Microsoft Windows, ATSUI and Core Text for macOS, and Pango for GTK+ and the GNOME desktop.


title: Unicode

text: Because keyboard layouts cannot have simple key combinations for all characters, several operating systems provide alternative input methods that allow access to the entire repertoire.


title: Unicode

text: ISO/IEC 14755, which standardises methods for entering Unicode characters from their code points, specifies several methods. There is the "Basic method", where a "beginning sequence" is followed by the hexadecimal representation of the code point and the "ending sequence". There is also a "screen-selection entry method" specified, where the characters are listed in a table in a screen, such as with a character map program.


title: Unicode

text: Online tools for finding the code point for a known character include Unicode Lookup by Jonathan Hedley and Shapecatcher by Benjamin Milde. In Unicode Lookup, one enters a search key (e.g. "fractions"), and a list of corresponding characters with their code points is returned. In Shapecatcher, based on Shape context, one draws the character in a box and a list of characters approximating the drawing, with their code points, is returned.


title: Unicode

text: MIME defines two different mechanisms for encoding non-ASCII characters in email, depending on whether the characters are in email headers (such as the "Subject:"), or in the text body of the message; in both cases, the original character set is identified as well as a transfer encoding. For email transmission of Unicode, the UTF-8 character set and the Base64 or the Quoted-printable transfer encoding are recommended, depending on whether much of the message consists of ASCII characters. The details of the two different mechanisms are specified in the MIME standards and generally are hidden from users of email software.


title: Unicode

text: The IETF has defined a framework for internationalized email using UTF-8, and has updated several protocols in accordance with that framework.


title: Unicode

text: The adoption of Unicode in email has been very slow. Some East Asian text is still encoded in encodings such as ISO-2022, and some devices, such as mobile phones, still cannot correctly handle Unicode data. Support has been improving, however. Many major free mail providers such as Yahoo! Mail, Gmail, and Outlook.com support it.


title: Unicode

text: All W3C recommendations have used Unicode as their "document character set" since HTML 4.0. Web browsers have supported Unicode, especially UTF-8, for many years. There used to be display problems resulting primarily from font related issues; e.g. v6 and older of Microsoft Internet Explorer did not render many code points unless explicitly told to use a font that contains them.


title: Unicode

text: Although syntax rules may affect the order in which characters are allowed to appear, XML (including XHTML) documents, by definition, comprise characters from most of the Unicode code points, with the exception of:


title: Unicode

text: HTML characters manifest either directly as bytes according to document's encoding, if the encoding supports them, or users may write them as numeric character references based on the character's Unicode code point. For example, the references codice_2, codice_3, codice_4, codice_5, codice_6, codice_7, codice_8, codice_9, and codice_10 (or the same numeric values expressed in hexadecimal, with codice_11 as the prefix) should display on all browsers as Δ, Й, ק ,م, ๗, あ, 叶, 葉, and 말.


title: Unicode

text: When specifying URIs, for example as URLs in HTTP requests, non-ASCII characters must be percent-encoded.


title: Unicode

text: Unicode is not in principle concerned with fonts "per se", seeing them as implementation choices. Any given character may have many allographs, from the more common bold, italic and base letterforms to complex decorative styles. A font is "Unicode compliant" if the glyphs in the font can be accessed using code points defined in the Unicode standard. The standard does not specify a minimum number of characters that must be included in the font; some fonts have quite a small repertoire.


title: Unicode

text: Free and retail fonts based on Unicode are widely available, since TrueType and OpenType support Unicode (and Web Open Font Format (WOFF and WOFF2) is based on those). These font formats map Unicode code points to glyphs, but OpenType and TrueType font files are restricted to 65,535 glyphs. Collection files provide a "gap mode" mechanism for overcoming this limit in a single font file. (Each font within the collection still has the 65,535 limit, however.) A TrueType Collection file would typically have a file extension of ".ttc".


title: Unicode

text: Thousands of fonts exist on the market, but fewer than a dozen fonts—sometimes described as "pan-Unicode" fonts—attempt to support the majority of Unicode's character repertoire. Instead, Unicode-based fonts typically focus on supporting only basic ASCII and particular scripts or sets of characters or symbols. Several reasons justify this approach: applications and documents rarely need to render characters from more than one or two writing systems; fonts tend to demand resources in computing environments; and operating systems and applications show increasing intelligence in regard to obtaining glyph information from separate font files as needed, i.e., font substitution. Furthermore, designing a consistent set of rendering instructions for tens of thousands of glyphs constitutes a monumental task; such a venture passes the point of diminishing returns for most typefaces.


title: Unicode

text: Unicode partially addresses the newline problem that occurs when trying to read a text file on different platforms. Unicode defines a large number of characters that conforming applications should recognize as line terminators.


title: Unicode

text: In terms of the newline, Unicode introduced and . This was an attempt to provide a Unicode solution to encoding paragraphs and lines semantically, potentially replacing all of the various platform solutions. In doing so, Unicode does provide a way around the historical platform dependent solutions. Nonetheless, few if any Unicode solutions have adopted these Unicode line and paragraph separators as the sole canonical line ending characters. However, a common approach to solving this issue is through newline normalization. This is achieved with the Cocoa text system in Mac OS X and also with W3C XML and HTML recommendations. In this approach every possible newline character is converted internally to a common newline (which one does not really matter since it is an internal operation just for rendering). In other words, the text system can correctly treat the character as a newline, regardless of the input's actual encoding.


title: Unicode

text: Han unification (the identification of forms in the East Asian languages which one can treat as stylistic variations of the same historical character) has become one of the most controversial aspects of Unicode, despite the presence of a majority of experts from all three regions in the Ideographic Research Group (IRG), which advises the Consortium and ISO on additions to the repertoire and on Han unification.


title: Unicode

text: Unicode has been criticized for failing to separately encode older and alternative forms of kanji which, critics argue, complicates the processing of ancient Japanese and uncommon Japanese names. This is often due to the fact that Unicode encodes characters rather than glyphs (the visual representations of the basic character that often vary from one language to another). Unification of glyphs leads to the perception that the languages themselves, not just the basic character representation, are being merged. There have been several attempts to create alternative encodings that preserve the stylistic differences between Chinese, Japanese, and Korean characters in opposition to Unicode's policy of Han unification. An example of one is TRON (although it is not widely adopted in Japan, there are some users who need to handle historical Japanese text and favor it).


title: Unicode

text: Although the repertoire of fewer than 21,000 Han characters in the earliest version of Unicode was largely limited to characters in common modern usage, Unicode now includes more than 97,000 Han characters, and work is continuing to add thousands more historic and dialectal characters used in China, Japan, Korea, Taiwan, and Vietnam.


title: Unicode

text: Modern font technology provides a means to address the practical issue of needing to depict a unified Han character in terms of a collection of alternative glyph representations, in the form of Unicode variation sequences. For example, the Advanced Typographic tables of OpenType permit one of a number of alternative glyph representations to be selected when performing the character to glyph mapping process. In this case, information can be provided within plain text to designate which alternate character form to select.


title: Unicode

text: If the appropriate glyphs for characters in the same script differ only in the italic, Unicode has generally unified them, as can be seen in the comparison among a set of seven characters' italic glyphs as typically appearing in Russian, traditional Bulgarian, Macedonian and Serbian texts at right, meaning that the differences are displayed through smart font technology or manually changing fonts.


title: Unicode

text: Unicode was designed to provide code-point-by-code-point round-trip format conversion to and from any preexisting character encodings, so that text files in older character sets can be converted to Unicode and then back and get back the same file, without employing context-dependent interpretation. That has meant that inconsistent legacy architectures, such as combining diacritics and precomposed characters, both exist in Unicode, giving more than one method of representing some text. This is most pronounced in the three different encoding forms for Korean Hangul. Since version 3.0, any precomposed characters that can be represented by a combining sequence of already existing characters can no longer be added to the standard in order to preserve interoperability between software using different versions of Unicode.


title: Unicode

text: Injective mappings must be provided between characters in existing legacy character sets and characters in Unicode to facilitate conversion to Unicode and allow interoperability with legacy software. Lack of consistency in various mappings between earlier Japanese encodings such as Shift-JIS or EUC-JP and Unicode led to round-trip format conversion mismatches, particularly the mapping of the character JIS X 0208 '～' (1-33, WAVE DASH), heavily used in legacy database data, to either (in Microsoft Windows) or (other vendors).


title: Unicode

text: Some Japanese computer programmers objected to Unicode because it requires them to separate the use of and , which was mapped to 0x5C in JIS X 0201, and a lot of legacy code exists with this usage. (This encoding also replaces tilde '~' 0x7E with macron '¯', now 0xAF.) The separation of these characters exists in ISO 8859-1, from long before Unicode.


title: Unicode

text: Indic scripts such as Tamil and Devanagari are each allocated only 128 code points, matching the ISCII standard. The correct rendering of Unicode Indic text requires transforming the stored logical order characters into visual order and the forming of ligatures (aka conjuncts) out of components. Some local scholars argued in favor of assignments of Unicode code points to these ligatures, going against the practice for other writing systems, though Unicode contains some Arabic and other ligatures for backward compatibility purposes only. Encoding of any new ligatures in Unicode will not happen, in part because the set of ligatures is font-dependent, and Unicode is an encoding independent of font variations. The same kind of issue arose for the Tibetan script in 2003 when the Standardization Administration of China proposed encoding 956 precomposed Tibetan syllables, but these were rejected for encoding by the relevant ISO committee (ISO/IEC JTC 1/SC 2).


title: Unicode

text: Thai alphabet support has been criticized for its ordering of Thai characters. The vowels เ, แ, โ, ใ, ไ that are written to the left of the preceding consonant are in visual order instead of phonetic order, unlike the Unicode representations of other Indic scripts. This complication is due to Unicode inheriting the Thai Industrial Standard 620, which worked in the same way, and was the way in which Thai had always been written on keyboards. This ordering problem complicates the Unicode collation process slightly, requiring table lookups to reorder Thai characters for collation. Even if Unicode had adopted encoding according to spoken order, it would still be problematic to collate words in dictionary order. E.g., the word "perform" starts with a consonant cluster "สด" (with an inherent vowel for the consonant "ส"), the vowel แ-, in spoken order would come after the ด, but in a dictionary, the word is collated as it is written, with the vowel following the ส.


title: Unicode

text: Characters with diacritical marks can generally be represented either as a single precomposed character or as a decomposed sequence of a base letter plus one or more non-spacing marks. For example, ḗ (precomposed e with macron and acute above) and ḗ (e followed by the combining macron above and combining acute above) should be rendered identically, both appearing as an e with a macron and acute accent, but in practice, their appearance may vary depending upon what rendering engine and fonts are being used to display the characters. Similarly, underdots, as needed in the romanization of Indic, will often be placed incorrectly.. Unicode characters that map to precomposed glyphs can be used in many cases, thus avoiding the problem, but where no precomposed character has been encoded the problem can often be solved by using a specialist Unicode font such as Charis SIL that uses Graphite, OpenType, or AAT technologies for advanced rendering features.


title: Unicode

text: The Unicode standard has imposed rules intended to guarantee stability. Depending on the strictness of a rule, a change can be prohibited or allowed. For example, a "name" given to a code point cannot and will not change. But a "script" property is more flexible, by Unicode's own rules. In version 2.0, Unicode changed many code point "names" from version 1. At the same moment, Unicode stated that from then on, an assigned name to a code point would never change anymore. This implies that when mistakes are published, these mistakes cannot be corrected, even if they are trivial (as happened in one instance with the spelling for in a character name). In 2006 a list of anomalies in character names was first published, and, as of June 2021, there were 104 characters with identified issues, for example:


title: Unicode

text: While Unicode defines the script designator (name) to be "", in that script's character names a hyphen is added: .


title: Unicode

text: Unicode has a large number of homoglyphs, many of which look very similar or identical to ASCII letters. Substitution of these can make an identifier or URL that looks correct, but directs to a different location than expected, and could also be used for manipulating the output of natural language processing (NLP) systems.


title: Unicode

text: Mitigation requires disallowing these characters, displaying them differently, or requiring that they resolve to the same identifier; all of this is complicated due to the huge and constantly changing set of characters.


title: Unicode

text: A security advisory was released in 2021 from two researchers, one from the University of Cambridge and the other from the same and from the University of Edinburgh, in which they assert that the BIDI codes can be used to make large sections of code do something different from what they appear to do.


title: Cockroach

text: Cockroaches (or roaches) are a paraphyletic group of insects belonging to Blattodea, containing all members of the group except termites. About 30 cockroach species out of 4,600 are associated with human habitats. Some species are well-known as pests.


title: Cockroach

text: The cockroaches are an ancient group, with their ancestors, known as "roachoids", originating during the Carboniferous period, some 320 million years ago. Those early ancestors, however, lacked the internal ovipositors of modern roaches. Cockroaches are somewhat generalized insects lacking special adaptations (such as the sucking mouthparts of aphids and other true bugs); they have chewing mouthparts and are probably among the most primitive of living Neopteran insects. They are common and hardy insects capable of tolerating a wide range of climates, from Arctic cold to tropical heat. Tropical cockroaches are often much larger than temperate species.


title: Cockroach

text: Modern cockroaches are not considered to be a monophyletic group, as it has been found based on genetics that termites are deeply nested within the group, with some groups of cockroaches more closely related to termites than they are to other cockroaches.


title: Cockroach

text: Some species, such as the gregarious German cockroach, have an elaborate social structure involving common shelter, social dependence, information transfer and kin recognition. Cockroaches have appeared in human culture since classical antiquity. They are popularly depicted as dirty pests, although the majority of species are inoffensive and live in a wide range of habitats around the world.


title: Cockroach

text: Cockroaches are members of the superorder Dictyoptera, which includes the termites and mantids, a group of insects once thought to be separate from cockroaches. Currently, 4,600 species and over 460 genera are described worldwide. The name "cockroach" comes from the Spanish word for cockroach, "cucaracha", transformed by 1620s English folk etymology into "cock" and "roach". The scientific name derives from the Latin "blatta", "an insect that shuns the light", which in classical Latin was applied not only to cockroaches, but also to mantids.


title: Cockroach

text: Historically, the name Blattaria was used largely interchangeably with the name Blattodea, but whilst Blattaria was used to refer to 'true' cockroaches exclusively, the Blattodea also includes the termites. The current catalogue of world cockroach species uses the name Blattodea for the group. Another name, Blattoptera, is also sometimes used to refer to extinct cockroach relatives. The earliest cockroach-like fossils ("blattopterans" or "roachoids") are from the Carboniferous period 320 million years ago, as are fossil roachoid nymphs.


title: Cockroach

text: According to one hypothesis, cockroaches were an ancient group of insects that arose during the Devonian period. Fossil roachoids that lived during that time differ from modern cockroaches in that they had long external ovipositors and are the ancestors of mantises, as well as modern cockroaches. As the body, hind wings and mouthparts are not preserved in fossils frequently, the relationship of these roachoids and modern cockroaches remains disputed. The first fossils of modern cockroaches with internal ovipositors appeared in the early Cretaceous. A recent phylogenetic analysis suggests that cockroaches originated at least in the Jurassic.


title: Cockroach

text: The evolutionary relationships of the Blattodea (cockroaches and termites) shown in the cladogram are based on Inward, Beccaloni and Eggleton (2007). The cockroach families Anaplectidae, Lamproblattidae, and Tryonicidae are not shown but are placed within the superfamily Blattoidea. The cockroach families Corydiidae and Ectobiidae were previously known as the Polyphagidae and Blattellidae.


title: Cockroach

text: Termites were previously regarded as a separate order Isoptera to cockroaches. However, recent genetic evidence strongly suggests that they evolved directly from 'true' cockroaches, and many authors now place them as an "epifamily" of Blattodea. This evidence supported a hypothesis suggested in 1934 that termites are closely related to the wood-eating cockroaches (genus "Cryptocercus"). This hypothesis was originally based on similarity of the symbiotic gut flagellates in termites regarded as living fossils and wood-eating cockroaches. Additional evidence emerged when F. A. McKittrick (1965) noted similar morphological characteristics between some termites and cockroach nymphs. The similarities among these cockroaches and termites have led some scientists to reclassify termites as a single family, the Termitidae, within the order Blattodea. Other scientists have taken a more conservative approach, proposing to retain the termites as the Termitoidae, an epifamily within the order. Such a measure preserves the classification of termites at family level and below.


title: Cockroach

text: Most species of cockroach are about the size of a thumbnail, but several species are larger. The world's heaviest cockroach is the Australian giant burrowing cockroach "Macropanesthia rhinoceros", which can reach in length and weigh up to . Comparable in size is the Central American giant cockroach "Blaberus giganteus". The longest cockroach species is "Megaloblatta longipennis", which can reach in length and across. A Central and South American species, "Megaloblatta blaberoides", has the largest wingspan of up to . At the other end of the size scale, "Attaphila" cockroaches that live with leaf-cutter ants include some of the world's smallest species, growing to about 3.5 mm in length.


title: Cockroach

text: Cockroaches are generalized insects with few special adaptations, and may be among the most primitive living Neopteran insects. They have a relatively small head and a broad, flattened body, and most species are reddish-brown to dark brown. They have large compound eyes, two ocelli, and long, flexible antennae. The mouthparts are on the underside of the head and include generalized chewing mandibles, salivary glands and various touch and taste receptors.


title: Cockroach

text: The body is divided into a thorax of three segments and a ten-segmented abdomen. The external surface has a tough exoskeleton which contains calcium carbonate; this protects the inner organs and provides attachment to muscles. This external exoskeleton is coated with wax to repel water. The wings are attached to the second and third thoracic segments. The tegmina, or first pair of wings, are tough and protective; these lay as a shield on top of the membranous hind wings, which are used in flight. All four wings have branching longitudinal veins, as well as multiple cross-veins.


title: Cockroach

text: The three pairs of legs are sturdy, with large coxae and five claws each. They are attached to each of the three thoracic segments. Of these, the front legs are the shortest and the hind legs the longest, providing the main propulsive power when the insect runs. The spines on the legs were earlier considered to be sensory, but observations of the insect's gait on sand and wire meshes have demonstrated that they help in locomotion on difficult terrain. The structures have been used as inspiration for robotic legs.


title: Cockroach

text: The abdomen has ten segments, each having a pair of spiracles for respiration. In addition to the spiracles, the final segment consists of a pair of cerci, a pair of anal styles, the anus and the external genitalia. Males have an aedeagus through which they secrete sperm during copulation, while females have spermatheca for storing sperm and an ovipositor through which the oothecae are laid.


title: Cockroach

text: Cockroaches are abundant throughout the world and live in a wide range of environments, especially in the tropics and subtropics. Cockroaches can withstand extremely low temperatures, allowing them to live in the Arctic. Some species are capable of surviving temperatures of by manufacturing an antifreeze made out of glycerol. In North America, 50 species separated into five families are found throughout the continent. 450 species are found in Australia. Only about four widespread species are commonly regarded as pests.


title: Cockroach

text: Cockroaches occupy a wide range of habitats. Many live in leaf litter, among the stems of matted vegetation, in rotting wood, in holes in stumps, in cavities under bark, under log piles and among debris. Some live in arid regions and have developed mechanisms to survive without access to water sources. Others are aquatic, living near the surface of water bodies, including bromeliad phytotelmata, and diving to forage for food. Most of these respire by piercing the water surface with the tip of the abdomen which acts as a snorkel, but some carry a bubble of air under their thoracic shield when they submerge. Others live in the forest canopy where they may be one of the main types of invertebrate present. Here they may hide during the day in crevices, among dead leaves, in bird and insect nests or among epiphytes, emerging at night to feed.


title: Cockroach

text: Cockroaches are social insects; a large number of species are either gregarious or inclined to aggregate, and a slightly smaller number exhibit parental care. It used to be thought that cockroaches aggregated because they were reacting to environmental cues, but it is now believed that pheromones are involved in these behaviors. Some species secrete these in their feces with gut microbial symbionts being involved, while others use glands located on their mandibles. Pheromones produced by the cuticle may enable cockroaches to distinguish between different populations of cockroach by odor. The behaviors involved have been studied in only a few species, but German cockroaches leave fecal trails with an odor gradient. Other cockroaches follow such trails to discover sources of food and water, and where other cockroaches are hiding. Thus, cockroaches have emergent behavior, in which group or swarm behavior emerges from a simple set of individual interactions.


title: Cockroach

text: Daily rhythms may also be regulated by a complex set of hormonal controls of which only a small subset have been understood. In 2005, the role of one of these proteins, pigment dispersing factor (PDF), was isolated and found to be a key mediator in the circadian rhythms of the cockroach.


title: Cockroach

text: Pest species adapt readily to a variety of environments, but prefer warm conditions found within buildings. Many tropical species prefer even warmer environments. Cockroaches are mainly nocturnal and run away when exposed to light. An exception to this is the Asian cockroach, which flies mostly at night but is attracted to brightly lit surfaces and pale colors.


title: Cockroach

text: Gregarious cockroaches display collective decision-making when choosing food sources. When a sufficient number of individuals (a "quorum") exploits a food source, this signals to newcomer cockroaches that they should stay there longer rather than leave for elsewhere. Other mathematical models have been developed to explain aggregation dynamics and conspecific recognition.


title: Cockroach

text: Cockroaches appear to use just two pieces of information to decide where to go, namely how dark it is and how many other cockroaches there are. A study used specially scented roach-sized robots that seem real to the roaches to demonstrate that once there are enough insects in a place to form a critical mass, the roaches accepted the collective decision on where to hide, even if this was an unusually lit place.


title: Cockroach

text: When reared in isolation, German cockroaches show behavior that is different from behavior when reared in a group. In one study, isolated cockroaches were less likely to leave their shelters and explore, spent less time eating, interacted less with conspecifics when exposed to them, and took longer to recognize receptive females. Because these changes occurred in many contexts, the authors suggested them as constituting a behavioral syndrome. These effects might have been due either to reduced metabolic and developmental rates in isolated individuals or the fact that the isolated individuals had not had a training period to learn about what others were like via their antennae.


title: Cockroach

text: Individual American cockroaches appear to have consistently different "personalities" regarding how they seek shelter. In addition, group personality is not simply the sum of individual choices, but reflects conformity and collective decision-making.


title: Cockroach

text: The gregarious German and American cockroaches have elaborate social structure, chemical signaling, and "social herd" characteristics. Lihoreau and his fellow researchers stated:


title: Cockroach

text: There is evidence that a few species of group-living roaches in the genera "Melyroidea" and "Aclavoidea" may exhibit a reproductive division of labor, which, if confirmed, would make these the only genuinely eusocial lineage known among roaches, in contrast to the subsocial members of the genus "Cryptocercus".


title: Cockroach

text: Some species make a buzzing noise while other cockroaches make a chirping noise. "Gromphadorhina" species and "Archiblatta hoeveni" produce sound through the modified spiracles on the fourth abdominal segment. In the former species, several different hisses are produced, including disturbance sounds, produced by adults and larger nymphs; and aggressive, courtship and copulatory sounds produced by adult males.


title: Cockroach

text: "Henschoutedenia epilamproides" has a stridulatory organ between its thorax and abdomen, but the purpose of the sound produced is unclear.


title: Cockroach

text: Several Australian species practice acoustic and vibration behaviour as an aspect of courtship. They have been observed producing hisses and whistles from air forced through the spiracles. Furthermore, in the presence of a potential mate, some cockroaches tap the substrate in a rhythmic, repetitive manner. Acoustic signals may be of greater prevalence amongst perching species, particularly those that live on low vegetation in Australia's tropics.


title: Cockroach

text: Cockroaches are generally omnivorous; the American cockroach ("Periplaneta americana"), for example, feeds on a great variety of foodstuffs including bread, fruit, leather, starch in book bindings, paper, glue, skin flakes, hair, dead insects and soiled clothing. Many species of cockroach harbor in their gut symbiotic protozoans and bacteria which are able to digest cellulose. In many species, these symbionts may be essential if the insect is to utilize cellulose; however, some species secrete cellulase in their saliva, and the wood-eating cockroach, "Panesthia cribrata", is able to survive indefinitely on a diet of crystallized cellulose while being free of microorganisms.


title: Cockroach

text: The similarity of these symbionts in the genus "Cryptocercus" to those in termites are such that these cockroaches have been suggested to be more closely related to termites than to other cockroaches, and current research strongly supports this hypothesis about their relationships. All species studied so far carry the obligate mutualistic endosymbiont bacterium "Blattabacterium", with the exception of "Nocticola", an Australian cave-dwelling genus without eyes, pigment or wings, which recent genetic studies indicate is a very primitive cockroach. It had previously been thought that all five families of cockroach were descended from a common ancestor that was infected with "B. cuenoti". It may be that "N. australiensis" subsequently lost its symbionts, or alternatively this hypothesis will need to be re-examined.


title: Cockroach

text: Like other insects, cockroaches breathe through a system of tubes called tracheae which are attached to openings called spiracles on all body segments. When the carbon dioxide level in the insect rises high enough, valves on the spiracles open and carbon dioxide diffuses out and oxygen diffuses in. The tracheal system branches repeatedly, the finest tracheoles bringing air directly to each cell, allowing gaseous exchange to take place.


title: Cockroach

text: While cockroaches do not have lungs as do vertebrates, and can continue to respire if their heads are removed, in some very large species, the body musculature may contract rhythmically to forcibly move air in and out of the spiracles; this may be considered a form of breathing.


title: Cockroach

text: Cockroaches use pheromones to attract mates, and the males practice courtship rituals, such as posturing and stridulation. Like many insects, cockroaches mate facing away from each other with their genitalia in contact, and copulation can be prolonged. A few species are known to be parthenogenetic, reproducing without the need for males.


title: Cockroach

text: Female cockroaches are sometimes seen carrying egg cases on the end of their abdomens; the German cockroach holds about 30 to 40 long, thin eggs in a case called an ootheca. She drops the capsule prior to hatching, though live births do occur in rare instances. The egg capsule may take more than five hours to lay and is initially bright white in color. The eggs are hatched from the combined pressure of the hatchlings gulping air. The hatchlings are initially bright white nymphs and continue inflating themselves with air, becoming harder and darker within about four hours. Their transient white stage while hatching and later while molting has led to claims of albino cockroaches. Development from eggs to adults takes three to four months. Cockroaches live up to a year, and the female may produce up to eight egg cases in a lifetime; in favorable conditions, she can produce 300 to 400 offspring. Other species of cockroaches, however, can produce far more eggs; in some cases a female needs to be impregnated only once to be able to lay eggs for the rest of her life.


title: Cockroach

text: The female usually attaches the egg case to a substrate, inserts it into a suitably protective crevice, or carries it about until just before the eggs hatch. Some species, however, are ovoviviparous, keeping the eggs inside their body, with or without an egg case, until they hatch. At least one genus, "Diploptera", is fully viviparous.


title: Cockroach

text: Cockroaches have incomplete metamorphosis, meaning that the nymphs are generally similar to the adults, except for undeveloped wings and genitalia. Development is generally slow, and may take a few months to over a year. The adults are also long-lived; some have survived for as many as four years in the laboratory.


title: Cockroach

text: When female American cockroaches ("Periplaneta americana") are housed in groups, this close association promotes parthenogenic reproduction. Oothecae, a type of egg mass, are produced asexually. The parthenogenetic process by which eggs are produced in "P. americana" is automixis. During automixis, meiosis occurs, but instead of giving rise to haploid gametes as ordinarily occurs, diploid gametes are produced (probably by terminal fusion) that can then develop into female cockroaches.


title: Cockroach

text: Cockroaches are among the hardiest insects. Some species are capable of remaining active for a month without food and are able to survive on limited resources, such as the glue from the back of postage stamps. Some can go without air for 45 minutes. Japanese cockroach ("Periplaneta japonica") nymphs, which hibernate in cold winters, have survived twelve hours at in laboratory experiments.


title: Cockroach

text: Experiments on decapitated specimens of several species of cockroach found a variety of behavioral functionality remained, including shock avoidance and escape behavior, although many insects other than cockroaches are also able to survive decapitation, and popular claims of the longevity of headless cockroaches do not appear to be based on published research. The severed head is able to survive and wave its antennae for several hours, or longer when refrigerated and given nutrients.


title: Cockroach

text: It is popularly suggested that cockroaches will "inherit the earth" if humanity destroys itself in a nuclear war. While cockroaches do, indeed, have a much higher radiation resistance than vertebrates, with a lethal dose perhaps six to 15 times that for humans, they are not exceptionally radiation-resistant compared to other insects, such as the fruit fly.


title: Cockroach

text: The cockroach's ability to withstand radiation has been explained through the cell cycle. Cells are most vulnerable to the effects of radiation while they are dividing. A cockroach's cells divide only once each molting cycle (which is weekly, for the juvenile German cockroach). Since not all cockroaches would be molting at the same time, many would be unaffected by an acute burst of radiation, although lingering and more acute radiation would still be harmful.


title: Cockroach

text: Because of their ease of rearing and resilience, cockroaches have been used as insect models in the laboratory, particularly in the fields of neurobiology, reproductive physiology and social behavior. The cockroach is a convenient insect to study as it is large and simple to raise in a laboratory environment. This makes it suitable both for research and for school and undergraduate biology studies. It can be used in experiments on topics such as learning, sexual pheromones, spatial orientation, aggression, activity rhythms and the biological clock, and behavioral ecology. Research conducted in 2014 suggests that humans fear cockroaches the most, even more than mosquitoes, due to an evolutionary aversion.


title: Cockroach

text: The Blattodea include some thirty species of cockroaches associated with humans; these species are atypical of the thousands of species in the order. They feed on human and pet food and can leave an offensive odor. They can passively transport pathogenic microbes on their body surfaces, particularly in environments such as hospitals. Cockroaches are linked with allergic reactions in humans. One of the proteins that trigger allergic reactions is tropomyosin, which can cause cross-reactive allergy to dust mites and shrimp. These allergens are also linked with asthma. Some species of cockroach can live for up to a month without food, so just because no cockroaches are visible in a home does not mean that they are not there. Approximately 20–48% of homes with no visible sign of cockroaches have detectable cockroach allergens in dust.


title: Cockroach

text: Many remedies have been tried in the search for control of the major pest species of cockroaches, which are resilient and fast-breeding. Household chemicals like sodium bicarbonate (baking soda) have been suggested, without evidence for their effectiveness. Garden herbs including bay, catnip, mint, cucumber, and garlic have been proposed as repellents. Poisoned bait containing hydramethylnon or fipronil, and boric acid powder is effective on adults. Baits with egg killers are also quite effective at reducing the cockroach population. Alternatively, insecticides containing deltamethrin or pyrethrin are very effective. In Singapore and Malaysia, taxi drivers use pandan leaves to repel cockroaches in their vehicles. Natural methods of cockroach control have been advanced by several published studies especially by "Metarhizium robertsii" (syn. "M. anisopliae").


title: Cockroach

text: Some parasites and predators are effective for biological control of cockroaches. Parasitoidal wasps such as "Ampulex" wasps sting nerve ganglia in the cockroach's thorax, causing temporary paralysis and allowing the wasp to deliver an incapacitating sting into the cockroach's brain. The wasp clips the antennae with its mandibles and drinks some hemolymph before dragging the prey to a burrow, where an egg (rarely two) is laid on it. The wasp larva feeds on the subdued living cockroach. Another wasp considered to be a promising candidate for biological control is the ensign wasp "Evania appendigaster", which attacks cockroach oothecae to lay a single egg inside. Ongoing research is still developing technologies allowing for mass-rearing these wasps for application releases. Widow spiders commonly prey on cockroaches.


title: Cockroach

text: Cockroaches can be trapped in a deep, smooth-walled jar baited with food inside, placed so that cockroaches can reach the opening, for example with a ramp of card or twigs on the outside. An inch or so of water or stale beer (by itself a cockroach attractant) in the jar can be used to drown any insects thus captured. The method works well with the American cockroach, but less so with the German cockroach.


title: Cockroach

text: A study conducted by scientists at Purdue University concluded that the most common cockroaches in the US, Australia and Europe were able to develop a “cross resistance” to multiple types of pesticide. This contradicted previous understanding that the animals can develop resistance against one pesticide at a time. The scientists suggested that cockroaches will no longer be easily controlled using a diverse spectrum of chemical pesticides and that a mix of other means, such as traps and better sanitation, will need to be employed.


title: Cockroach

text: Researcher from Heriot-Watt university demonstrated that power laser can with high effectivity neutralise cockroach in home, that can be alternative for pesticide.


title: Cockroach

text: Although considered disgusting in Western culture, cockroaches are eaten in many places around the world. Whereas household pest cockroaches may carry bacteria and viruses, cockroaches bred under laboratory conditions can be used to prepare nutritious food. In Thailand and Mexico, the heads and legs are removed, and the remainder may be boiled, sautéed, grilled, dried or diced. In China, cockroaches have become popular as medicine and cockroach farming is rising with over 100 farms.


title: Cockroach

text: The cockroaches are fried twice in a wok of hot oil, which makes them crispy with soft innards that are like cottage cheese. Fried cockroaches are ground and sold as pills for stomach, heart and liver diseases. A cockroach recipe from Formosa (Taiwan) specifies salting and frying cockroaches after removing the head and entrails.


title: Cockroach

text: While a small minority of cockroaches are associated with human habitats and viewed as repugnant by many people, a few species are of conservation concern. The Lord Howe Island wood-feeding cockroach ("Panesthia lata") is listed as endangered by the New South Wales Scientific Committee, but the cockroach may be extinct on Lord Howe Island itself. The introduction of rats, the spread of Rhodes grass ("Chloris gayana") and fires are possible reasons for their scarcity. Two species are currently listed as endangered and critically endangered by the IUCN Red List, "Delosia ornata" and "Nocticola gerlachi". Both cockroaches have a restricted distribution and are threatened by habitat loss and rising sea levels. Only 600 "Delosia ornata" adults and 300 nymphs are known to exist, and these are threatened by a hotel development. No action has been taken to save the two cockroach species, but protecting their natural habitats may prevent their extinction. In the former Soviet Union, cockroach populations have been declining at an alarming rate; this may be exaggerated, or the phenomenon may be temporary or cyclic. One species of roach, "Simandoa conserfariam", is considered extinct in the wild.


title: Cockroach

text: Cockroaches were known and considered repellent but medicinally useful in Classical times. An insect named in Greek "σίλφη" ("silphe") has been identified with the cockroach, though the scientific name "Silpha" refers to a genus of carrion beetles. It is mentioned by Aristotle, saying that it sheds its skin; it is described as foul-smelling in Aristophanes' play "Peace"; Euenus called it a pest of book collections, being "page-eating, destructive, black-bodied" in his "Analect". Virgil named the cockroach "Lucifuga" ("one that avoids light"). Pliny the Elder recorded the use of "Blatta" in various medicines; he describes the insect as disgusting, and as seeking out dark corners to avoid the light. Dioscorides recorded the use of the "Silphe", ground up with oil, as a remedy for earache.


title: Cockroach

text: Lafcadio Hearn (1850–1904) asserted that "For tetanus cockroach tea is given. I do not know how many cockroaches go to make up the cup; but I find that faith in this remedy is strong among many of the American population of New Orleans. A poultice of boiled cockroaches is placed over the wound." He adds that cockroaches are eaten, fried with garlic, for indigestion.


title: Cockroach

text: Several cockroach species, such as "Blaptica dubia", are raised as food for insectivorous pets. A few cockroach species are raised as pets, most commonly the giant Madagascar hissing cockroach, "Gromphadorhina portentosa". Whilst the hissing cockroaches may be the most commonly kept species, there are many species that are kept by cockroach enthusiasts; there is even a specialist society: the Blattodea Culture Group (BCG), which was a thriving organisation for about 15 years although now appears to be dormant. The BCG provided a source of literature for people interested in rearing cockroaches, which was otherwise limited to either scientific papers, general insect books, or books covering a variety of exotic pets; in the absence of an inclusive book, one member published "Introduction to Rearing Cockroaches", which still appears to be the only book dedicated to rearing cockroaches.


title: Cockroach

text: Cockroaches have been used for space tests. A cockroach given the name Nadezhda was sent into space by Russian scientists as part of a Foton-M mission, during which she mated, and later became the first terrestrial animal to produce offspring that had been conceived in space.


title: Cockroach

text: Because of their long association with humans, cockroaches are frequently referred to in popular culture. In Western culture, cockroaches are often depicted as dirty pests. In a 1750–1752 journal, Pehr Osbeck noted that cockroaches were frequently seen and found their way to the bakeries, after the sailing ship "Gothenburg" ran aground and was destroyed by rocks.


title: Cockroach

text: Donald Harington's satirical novel "The Cockroaches of Stay More" (Harcourt, 1989) imagines a community of "roosterroaches" in a mythical Ozark town where the insects are named after their human counterparts. Madonna has famously quoted, "I am a survivor. I am like a cockroach, you just can't get rid of me." An urban legend maintains that cockroaches are radiation-resistant, and thus would survive a nuclear war.


title: Lviv

text: Lviv () is the largest city in western Ukraine, and the seventh-largest in Ukraine, with a population of . It serves as the administrative centre of Lviv Oblast and Lviv Raion, and is one of the main cultural centres of Ukraine. It was named in honour of Leo, the eldest son of Daniel, King of Ruthenia.


title: Lviv

text: Lviv emerged as the centre of the historical regions of Red Ruthenia and Galicia in the 14th century, superseding Halych, Chełm, Belz and Przemyśl. It was the capital of the Kingdom of Galicia–Volhynia from 1272 to 1349, when it was conquered by King Casimir III the Great of Poland. From 1434, it was the regional capital of the Ruthenian Voivodeship in the Kingdom of Poland. In 1772, after the First Partition of Poland, the city became the capital of the Habsburg Kingdom of Galicia and Lodomeria. In 1918, for a short time, it was the capital of the West Ukrainian People's Republic. Between the wars, the city was the centre of the Lwów Voivodeship in the Second Polish Republic. After the German-Soviet invasion of Poland in 1939, Lviv became part of the Soviet Union.


title: Lviv

text: The once large Jewish community was sharply reduced in number by the Nazis during the Holocaust. For decades there was no working synagogue in the city after the final one was closed by the Soviets. The once predominant Polish population was for the greatest part sent to Poland in the context of a population exchange between Poland and Soviet Ukraine in 1944–46.


title: Lviv

text: The historical heart of the city, with its cobblestone streets and architectural assortment of Renaissance, Baroque, Neo-classicism and Art Nouveau, survived Soviet and German occupations during World War II largely unscathed. Due to its Mediterranean aura, many Soviet movies set in places like Venice or Rome were actually shot in Lviv. In 1991, Lviv became part of the independent nation of Ukraine.


title: Lviv

text: The city has many industries and institutions of higher education such as Lviv University and Lviv Polytechnic. Lviv is also the home of many cultural institutions, including a philharmonic orchestra and the Lviv Theatre of Opera and Ballet. The historic city centre is on the UNESCO World Heritage List.


title: Lviv

text: The coat of arms, the banner of the Lviv City Council and the logo are the officially approved symbols of Lviv. The names or images of architectural and historical monuments are also considered symbols of the city by the Statute of Lviv.


title: Lviv

text: Lviv's modern coat of arms is based on the coat of arms from the city seal from the middle of the 14th century—a stone gate with three towers, in the opening of the gate of which walks a golden lion. Lviv's large coat of arms is a shield with the coat of arms of the city, crowned with a silver city crown with three edges, held by a lion and an ancient warrior.


title: Lviv

text: Lviv's flag is a blue square banner with the city emblem image and yellow and blue triangles at the edges.


title: Lviv

text: Lviv's logo is an image of five colorful towers in Lviv and the slogan "Lviv — open to the world" under them. The Latin phrase "Semper fidelis" (Always True) was used as a motto on the former coat of arms of 1936–1939, but was no longer used after the Second World War.


title: Lviv

text: Lviv is on the edge of the Roztochia Upland, about 70 kilometres (43 miles) east of Polish border and 160 km (99 mi) north of the eastern Carpathian Mountains. The average altitude of Lviv is 296 metres (971 feet) above sea level. Its highest point is the "Vysokyi Zamok" (High Castle), 409 meters (1342 feet) above sea level. This castle has a commanding view of the historic city centre with its distinctive green-domed churches and intricate architecture.


title: Lviv

text: The old walled city was at the foothills of the High Castle on the banks of the Poltva River. In the 13th century, the river was used to transport goods. In the early 20th century, the Poltva was covered over in areas where it flows through the city; the river flows directly beneath Lviv's central street, Freedom Avenue ("Prospect Svobody"), and the Lviv Theatre of Opera and Ballet.


title: Lviv

text: Lviv's climate is humid continental (Köppen climate classification "Dfb") with cold winters and warm summers. The average temperatures are in January and in July. The average annual rainfall is with the maximum in summer. Mean sunshine duration per year at Lviv is about 1,804 hours.


title: Lviv

text: Archaeologists have demonstrated that the Lviv area was settled by the fifth century, with the gord at -Voznesensk Street in Lychakivskyi District attributed to White Croats. The city of Lviv was founded in 1250 by King Daniel of Galicia (1201–1264) in the Principality of Halych of Kingdom of Ruthenia and named in honour of his son Lev as Lvihorod which is consistent with names of other Ukrainian cities, such as Myrhorod, Sharhorod, Novhorod, Bilhorod, Horodyshche, and Horodok.


title: Lviv

text: Earlier there was a settlement in the form of a borough with a characteristic layout element—an elongated market square. Daniel's foundation of the stronghold was its next reconstruction after the Batu Khan invasion of 1240.


title: Lviv

text: Lviv was invaded by the Mongols in 1261. Various sources relate the events, which range from the destruction of the castle to a complete razing of the town. All sources agree that it was on the orders of the Mongol general Burundai. The Shevchenko Scientific Society ("Naukove tovarystvo im. Shevchenka") says that Burundai reduced the order to raze the city. The Galician-Volhynian chronicle states that in 1261 "Said Buronda to Vasylko: 'Since you are at peace with me then raze all your castles'". Basil Dmytryshyn states that the order was implied to be the fortifications as a whole: "If you wish to have peace with me, then destroy [all fortifications of] your towns". According to the "Universal-Lexicon der Gegenwart und Vergangenheit" the town's founder was ordered to destroy the town himself.


title: Lviv

text: After Daniel's death, King Lev rebuilt the town around 1270 at its present location, choosing Lviv as his residence, and made it the capital of Galicia-Volhynia. The city is first mentioned in the Halych-Volhynian Chronicle regarding the events that were dated 1256. The town grew quickly due to an influx of Polish people from Kraków, Poland, after they had suffered a widespread famine there. Around 1280 Armenians lived in Galicia and were mainly based in Lviv where they had their own Archbishop.


title: Lviv

text: In the 13th and early 14th centuries, Lviv was largely a wooden city, except for its several stone churches. Some of them, like the Church of Saint Nicholas, have survived, although in a thoroughly rebuilt form. The town was inherited by the Grand Duchy of Lithuania in 1340 and ruled by voivode Dmytro Dedko, the favourite of the Lithuanian prince Liubartas, until 1349.


title: Lviv

text: The region and the region adjacent to Lviv, Leopold, Poland, was a destination of 50,000 Armenians fleeing from the Saljuq and Mongol invasions of Armenia.


title: Lviv

text: During the wars over the succession of Galicia-Volhynia Principality in 1339 King Casimir III of Poland undertook an expedition and conquered Lviv in 1340, burning down the old princely castle. Poland ultimately gained control over Lviv and the adjacent region in 1349. From then on the population was subjected to attempts to both Polonize and Catholicize the population. The Lithuanians ravaged Lviv land in 1351 during the Halych-Volhyn Wars with Lviv being plundered and destroyed by Prince Liubartas in 1353.


title: Lviv

text: Casimir built a new city center (or founded a new town) in a basin, surrounded it by walls, and replaced the wooden palace by masonry castle – one of the two built by him. The old (Ruthenian) settlement, after it had been rebuilt, became known as the Krakovian Suburb.


title: Lviv

text: In 1349, the Kingdom of Ruthenia with its capital Lviv was annexed by the Crown of the Kingdom of Poland. The kingdom was transformed into the Ruthenian domain of the Crown with Lwów as the capital. On 17 June 1356 King Casimir III the Great granted it Magdeburg rights, which implied that all city matters were to be resolved by a council elected by the wealthy citizens. In 1362, the High Castle was completely rebuilt with stone replacing the previous wood. In 1358, the city became a seat of Roman Catholic Archdiocese, which initiated the spread of Latin Church onto the Ruthenian lands.


title: Lviv

text: After Casimir had died in 1370, he was succeeded as king of Poland by his nephew, King Louis I of Hungary, who in 1372 put Lwów together with the region of Kingdom of Galicia–Volhynia under the administration of his relative Vladislaus II of Opole, Duke of Opole. When in 1387 Władysław retreated from the post of its governor, Galicia-Volhynia became occupied by the Hungarians, but soon Jadwiga, the youngest daughter of Louis, but also the ruler of Poland and wife of King of Poland Władysław II Jagiełło, unified it directly with the Crown of the Kingdom of Poland.


title: Lviv

text: The city's prosperity during the following centuries is owed to the trade privileges granted to it by Casimir, King Jadwiga and the subsequent Polish monarchs. Germans, Poles and Czechs formed the largest groups of newcomers. Most of the settlers were polonised by the end of the 15th century, and the city became a Polish island surrounded by Orthodox Ruthenian population.


title: Lviv

text: In 1412, the local archdiocese has developed into the Roman Catholic Metropolis, which since 1375 as diocese had been in Halych. The new metropolis included regional diocese in Lwów, Przemyśl, Chełm, Włodzimierz, Łuck, Kamieniec, as well as Siret and Kijów (see Old Cathedral of St. Sophia, Kyiv). The first Catholic Archbishop who resided in Lwów was Jan Rzeszowski.


title: Lviv

text: In 1434, the Ruthenian domain of the Crown was transformed into the Ruthenian Voivodeship. In 1444, the city was granted the staple right, which resulted in its growing prosperity and wealth, as it became one of the major trading centres on the merchant routes between Central Europe and Black Sea region. It was also transformed into one of the main fortresses of the kingdom, and was a royal city, like Kraków or Gdańsk. During the 17th century, Lwów was the second largest city of the Polish–Lithuanian Commonwealth, with a population of about 30,000.


title: Lviv

text: In 1572, one of the first publishers of books in what is now Ukraine, Ivan Fedorov, a graduate of the University of Kraków, settled here for a brief period. The city became a significant centre for Eastern Orthodoxy with the establishment of an Orthodox brotherhood, a Greek-Slavonic school and a printer which published the first full versions of the Bible in Church Slavonic in 1580. A Jesuit Collegium was founded in 1608, and on 20 January 1661 King John II Casimir of Poland issued a decree granting it "the honour of the academy and the title of the university".


title: Lviv

text: The 17th century brought invading armies of Swedes, Hungarians, Turks, Russians and Cossacks to its gates. In 1648 an army of Cossacks and Crimean Tatars besieged the town. They captured the High Castle, murdering its defenders. The city itself was not sacked due to the fact that the leader of the revolution Bohdan Khmelnytsky accepted a ransom of 250,000 ducats, and the Cossacks marched north-west towards Zamość. It was one of two major cities in Poland which was not captured during the so-called "Deluge": the other one was Gdańsk (Danzig).


title: Lviv

text: At that time, Lwów witnessed a historic scene, as here King John II Casimir made his famous Lwów Oath. On 1 April 1656, during a holy mass in Lwów's Cathedral, conducted by the papal legate Pietro Vidoni, John Casimir in a grandiose and elaborate ceremony entrusted the Commonwealth under the Blessed Virgin Mary's protection, whom he announced as "The Queen of the Polish Crown and other of his countries". He also swore to "protect the Kingdom's folk from any impositions and unjust bondage".


title: Lviv

text: Two years later, John Casimir, in honour of the bravery of its residents, declared Lwów to be equal to two historic capitals of the Commonwealth, Kraków and Vilnius. In the same year, 1658, Pope Alexander VII declared the city to be Semper fidelis, in recognition of its key role in defending Europe and Roman Catholicism from Muslim invasion.


title: Lviv

text: In 1672 it was surrounded by the Ottomans who also failed to conquer it. Three years later, the Battle of Lwów (1675) took place near the city. Lwów was captured for the first time since the Middle Ages by a foreign army in 1704 when Swedish troops under King Charles XII entered the city after a short siege. The plague of the early 18th century caused the death of about 10,000 inhabitants (40% of the city's population).


title: Lviv

text: In 1772, following the First Partition of Poland, the region was annexed by the Habsburg monarchy to the Austrian Partition. Known in German as "Lemberg", the city became the capital of the Kingdom of Galicia and Lodomeria. Lemberg grew dramatically during the 19th century, increasing in population from approximately 30,000 at the time of the Austrian annexation in 1772, to 196,000 by 1910 and to 212,000 three years later; while the poverty in Austrian Galicia was raging. In the late 18th and early 19th centuries a large influx of Austrians and German-speaking Czech bureaucrats gave the city a character that by the 1840s was quite Austrian, in its orderliness and in the appearance and popularity of Austrian coffeehouses.


title: Lviv

text: During Habsburg's rule, Lviv became one of the most important Polish, Ukrainian and Jewish cultural centres. In Lviv, according to the Austrian census of 1910, which listed religion and language, 51% of the city's population was Roman Catholics, 28% Jews, and 19% belonged to the Ukrainian Greek Catholic Church. Linguistically, 86% of the city's population used the Polish language and 11% preferred the Ruthenian.


title: Lviv

text: In 1773, the first newspaper in Lemberg, "Gazette de Leopoli", began to be published. In 1784, a Latin language university was opened with lectures in German, Polish and even Ruthenian; after closing in 1805, it was reopened in 1817. By 1825, German became the sole language of instruction. Lemberg University was opened by Maria Theresa in 1784. By 1787, her successor Joseph II, Holy Roman Emperor opened "Studium Ruthenum" for students who did not know enough Latin to take regular courses.


title: Lviv

text: During the 19th century, the Austrian administration attempted to Germanise the city's educational and governmental institutions. Many cultural organisations which did not have a pro-German orientation were closed. After the revolutions of 1848, the language of instruction at the university shifted from German to include Ukrainian and Polish. Around that time, a certain sociolect developed in the city known as the Lwów dialect. Considered to be a type of Polish dialect, it draws its roots from numerous other languages besides Polish. In 1853, kerosene lamps as street lighting were introduced by Ignacy Łukasiewicz and Jan Zeh. Then in 1858, these were updated to gas lamps, and in 1900 to electric ones.


title: Lviv

text: After the so-called "Ausgleich" of February 1867, the Austrian Empire was reformed into a dualist Austria-Hungary and a slow yet steady process of liberalisation of Austrian rule in Galicia started. From 1873, Galicia was de facto an autonomous province of Austria-Hungary, with Polish and Ruthenian as official languages. Germanisation was halted and the censorship lifted as well. Galicia was subject to the Austrian part of the Dual Monarchy, but the Galician Sejm and provincial administration, both established in Lviv, had extensive privileges and prerogatives, especially in education, culture, and local affairs. In 1894, the General National Exhibition was held in Lviv. The city started to grow rapidly, becoming the fourth largest in Austria-Hungary, according to the census of 1910. Many Belle Époque public edifices and tenement houses were erected, with many of the buildings from the Austrian period, such as the Lviv Theatre of Opera and Ballet, built in the Viennese neo-Renaissance style.


title: Lviv

text: At that time, Lviv was home to a number of renowned Polish-language institutions, such as the Ossolineum, with the second-largest collection of Polish books in the world, the Polish Academy of Arts, the National Museum (since 1908), the Historical Museum of the City of Lwów (since 1891), the Polish Copernicus Society of Naturalists, the Polish Historical Society, Lwów University, with Polish as the official language since 1882, the Lwów Scientific Society, the Lwów Art Gallery, the Polish Theatre, and the Polish Archdiocese.


title: Lviv

text: Furthermore, Lviv was the centre of a number of Polish independence organisations. In June 1908, Józef Piłsudski, Władysław Sikorski and Kazimierz Sosnkowski founded here the Union of Active Struggle. Two years later, the paramilitary organisation, called the Riflemen's Association, was also founded in the city by Polish activists.


title: Lviv

text: At the same time, Lviv became the city where famous Ukrainian writers (such as Ivan Franko, Panteleimon Kulish and Ivan Nechuy-Levytsky) published their work. It was a centre of Ukrainian cultural revival. The city also housed the largest and most influential Ukrainian institutions in the world, including the Prosvita society dedicated to spreading literacy in the Ukrainian language, the Shevchenko Scientific Society, the Dniester Insurance Company and base of the Ukrainian cooperative movement, and it served as the seat of the Ukrainian Catholic Church. Lviv was also a major centre of Jewish culture, in particular as a centre of the Yiddish language, and was the home of the world's first Yiddish-language daily newspaper, the "Lemberger Togblat", established in 1904.


title: Lviv

text: In the Battle of Galicia at the early stages of the First World War, Lviv was captured by the Russian army in September 1914 following the Battle of Gnila Lipa. The Lemberg Fortress fell on 3 September. The historian Pál Kelemen provided a first-hand account of the chaotic evacuation of the city by the Austro-Hungarian Army and civilians alike.


title: Lviv

text: The town was retaken by Austria-Hungary in June the following year during the Gorlice–Tarnów offensive. Lviv and its population, therefore, suffered greatly during the First World War as many of the offensives were fought across its local geography causing significant collateral damage and disruption.


title: Lviv

text: After the collapse of the Habsburg Monarchy at the end of the First World War Lwów became an arena of battle between the local Polish population and the Ukrainian Sich Riflemen. Both nations perceived the city as an integral part of their new statehoods which at that time were forming in the former Austrian territories. On the night of 31 October – 1 November 1918 the Western Ukrainian People's Republic was proclaimed with Lwów as its capital. 2,300 Ukrainian soldiers from the Ukrainian Sich Riflemen (Sichovi Striltsi), which had previously been a corps in the Austrian Army, made an attempt to take over Lviv. The city's Polish majority opposed the Ukrainian declaration and began to fight against the Ukrainian troops. During this combat an important role was taken by young Polish city defenders called Lwów Eaglets.


title: Lviv

text: The Ukrainian forces withdrew outside Lwów's confines by 21 November 1918, after which elements of Polish soldiers began to loot and burn much of the Jewish and Ukrainian quarters of the city, killing approximately 340 civilians (see: Lwów pogrom). The retreating Ukrainian forces besieged the city. The Sich riflemen reformed into the Ukrainian Galician Army (UHA). The Polish forces aided from central Poland, including General Haller's "Blue Army", equipped by the French, relieved the besieged city in May 1919 forcing the UHA to the east.


title: Lviv

text: Despite Entente mediation attempts to cease hostilities and reach a compromise between belligerents the Polish–Ukrainian War continued until July 1919 when the last UHA forces withdrew east of the River Zbruch. The border on the River Zbruch was confirmed at the Treaty of Warsaw, when in April 1920 Field Marshal Piłsudski signed an agreement with Symon Petlura where it was agreed that for military support against the Bolsheviks the Ukrainian People's Republic renounced its claims to the territories of Eastern Galicia.


title: Lviv

text: In August 1920, Lwów was attacked by the Red Army under the command of Aleksandr Yegorov and Stalin during the Polish–Soviet War but the city repelled the attack. For the courage of its inhabitants Lwów was awarded the Virtuti Militari cross by Józef Piłsudski on 22 November 1920.


title: Lviv

text: On 23 February 1921, the council of the League of Nations declared that Galicia (including the city) lay outside the territory of Poland and that Poland did not have the mandate to establish administrative control in that country, and that Poland was merely the occupying military power of Galicia (as a whole), whose sovereign remained the Allied Powers and fate would be determined by the Council of Ambassadors at the League of Nations. On 14 March 1923, the Council of Ambassadors decided that Galicia would be incorporated into Poland "whereas it is recognised by Poland that ethnographical conditions necessitate an autonomous regime in the Eastern part of Galicia." "This proviso was never honoured by the interwar Polish government." After 1923, Galicia was internationally recognized as part of the Polish state.


title: Lviv

text: During the interwar period, Lwów held the rank of the Second Polish Republic's third most populous city (following Warsaw and Łódź), and it became the seat of the Lwów Voivodeship. Following Warsaw, Lwów was the second most important cultural and academic centre of interwar Poland. For example, in 1920 professor Rudolf Weigl of the Lwów University developed a vaccine against typhus fever. Furthermore, the geographic location of Lwów gave it an important role in stimulating international trade and fostering the city's and Poland's economic development. A major trade fair called "Targi Wschodnie" was established in 1921. In the academic year 1937–1938, there were 9,100 students attending five institutions of higher education, including the Lwów University as well as the Polytechnic.


title: Lviv

text: While about two-thirds of the city's inhabitants were Poles, some of whom spoke the characteristic Lwów dialect, the eastern part of the Lwów Voivodeship had a relative Ukrainian majority in most of its rural areas. Although Polish authorities obliged themselves internationally to provide Eastern Galicia with an autonomy (including a creation of a separate Ukrainian university in Lwów) and even though in September 1922 adequate Polish Sejm's Bill was enacted, it was not fulfilled.


title: Lviv

text: The Polish government discontinued many Ukrainian schools which functioned during the Austrian rule, and closed down Ukrainian departments at the University of Lwów with the exception of one. Prewar Lwów also had a large and thriving Jewish community, which constituted about a quarter of the population.


title: Lviv

text: Unlike in Austrian times, when the size and number of public parades or other cultural expressions corresponded to each cultural group's relative population, the Polish government emphasised the Polish nature of the city and limited public displays of Jewish and Ukrainian culture. Military parades and commemorations of battles at particular streets within the city, all celebrating the Polish forces who fought against the Ukrainians in 1918, became frequent, and in the 1930s a vast memorial monument and burial ground of Polish soldiers from that conflict was built in the city's Lychakiv Cemetery.


title: Lviv

text: Germany invaded Poland on 1 September 1939 and by 14 September Lwów was completely encircled by German Army units. Subsequently, the Soviets invaded Poland on 17 September. On 22 September 1939 Lwów capitulated to the Red Army. The USSR annexed the eastern half of the Second Polish Republic with Ukrainian and Belorussian populations. The city became the capital of the newly formed Lviv Oblast. The Soviets reopened uni-lingual Ukrainian schools, which were discontinued by the Polish government.


title: Lviv

text: The only change over imposed by the Soviets was the language of instruction, with the actual net loss of about 1,000 schools in short order. Ukrainian was made compulsory in the University of Lviv with almost all its books in Polish. It became thoroughly Ukrainized and was renamed after Ukrainian writer Ivan Franko. The Polish academics were laid off. Soviet rule turned out to be much more oppressive than Polish rule; the rich world of Ukrainian publications in Polish Lwów, for instance, was gone in Soviet Ukrainian Lviv, and many journalism jobs were lost with it.


title: Lviv

text: On 22 June 1941, Nazi Germany and several of its allies invaded the USSR. In the initial stage of Operation Barbarossa (30 June 1941) Lviv was taken by the Germans. The evacuating Soviets killed most of the prison population, with arriving Wehrmacht forces easily discovering evidence of the Soviet mass murders in the city committed by the NKVD and NKGB. Ukrainian nationalists, organised as a militia, and the civilian population was allowed to take revenge on the "Jews and the Bolsheviks" and indulged in several mass killings in Lviv and the surrounding region, which resulted in the deaths estimated at between 4,000 and 10,000 Jews. On 30 June 1941 Yaroslav Stetsko proclaimed in Lviv the Government of an independent Ukrainian state allied with Nazi Germany. This was done without preapproval from the Germans and after 15 September 1941, the organisers were arrested.


title: Lviv

text: The Sikorski–Mayski Agreement signed in London on 30 July 1941 between Polish government-in-exile and USSR's government invalidated the September 1939 Soviet-German partition of Poland, as the Soviets declared it null and void. Meanwhile, German-occupied Eastern Galicia at the beginning of August 1941 was incorporated into the General Government as "Distrikt Galizien" with Lviv as the district's capital. German policy towards the Polish population in this area was as harsh as in the rest of the General Government.


title: Lviv

text: Germans during the occupation of the city committed numerous atrocities including the killing of Polish university professors in 1941. German Nazis viewed the Ukrainian Galicians, former inhabitants of Austrian Crown Land, as to some point more aryanised and civilised than the Ukrainian population living in the territories belonging to the USSR before 1939. As a result, they escaped the full extent of German acts in comparison to Ukrainians who lived to the east, in the German-occupied Soviet Ukraine turned into the "Reichskommissariat Ukraine".


title: Lviv

text: According to the Third Reich's racial policies, local Jews then became the main target of German repressions in the region. Following the German occupation, the Jewish population was concentrated in the Lwów Ghetto established in the city's Zamarstynów (today "Zamarstyniv") district and the Janowska concentration camp was also set up. In the Janowska concentration camp, the Nazis conducted torture and executions to music. The Lviv National Opera members, who were prisoners, played one and the same tune, Tango of Death.


title: Lviv

text: On the eve of Lviv's liberation, German Nazis ordered 40 orchestra musicians to form a circle. The security ringed the musicians tightly and ordered them to play. First, the orchestra conductor, Mund, was executed. Then the commandant ordered the musicians to come to the center of the circle one by one, put their instruments onto the ground and strip naked, after which they were killed by a headshot. A photo of the orchestra players was one of the incriminating documents at the Nuremberg trials.


title: Lviv

text: In 1931 there were 75,316 Yiddish-speaking inhabitants, but by 1941 approximately 100,000 Jews were present in Lviv. The majority of these Jews were either killed within the city or deported to Belzec extermination camp. In the summer of 1943, on the orders of Heinrich Himmler, SS-Standartenführer Paul Blobel was tasked with the destruction of any evidence of Nazi mass murders in the Lviv area. On 15 June Blobel, using forced labourers from Janowska, dug up a number of mass graves and incinerated the remains.


title: Lviv

text: Later, on 19 November 1943, inmates at Janowska staged an uprising and attempted a mass escape. A few succeeded, but most were recaptured and killed. The SS staff and their local auxiliaries then, at the time of the Janowska camp's liquidation, murdered at least 6,000 more inmates, as well as the Jews in other forced labour camps in Galicia. By the end of the war, the Jewish population of the city was virtually eliminated, with only around 200 to 800 survivors remaining.