text stringlengths 26 3.6k | page_title stringlengths 1 71 | source stringclasses 1
value | token_count int64 10 512 | id stringlengths 2 8 | url stringlengths 31 117 | topic stringclasses 4
values | section stringlengths 4 49 ⌀ | sublist stringclasses 9
values |
|---|---|---|---|---|---|---|---|---|
A Schwarz triangle is a spherical triangle that can be used to tile a sphere.
Tessellations in non-Euclidean geometries
It is possible to tessellate in non-Euclidean geometries such as hyperbolic geometry. A uniform tiling in the hyperbolic plane (that may be regular, quasiregular, or semiregular) is an edge-to-edge filling of the hyperbolic plane, with regular polygons as faces; these are vertex-transitive (transitive on its vertices), and isogonal (there is an isometry mapping any vertex onto any other).
A uniform honeycomb in hyperbolic space is a uniform tessellation of uniform polyhedral cells. In three-dimensional (3-D) hyperbolic space there are nine Coxeter group families of compact convex uniform honeycombs, generated as Wythoff constructions, and represented by permutations of rings of the Coxeter diagrams for each family.
In art
In architecture, tessellations have been used to create decorative motifs since ancient times. Mosaic tilings often had geometric patterns. Later civilisations also used larger tiles, either plain or individually decorated. Some of the most decorative were the Moorish wall tilings of Islamic architecture, using Girih and Zellige tiles in buildings such as the Alhambra and La Mezquita.
Tessellations frequently appeared in the graphic art of M. C. Escher; he was inspired by the Moorish use of symmetry in places such as the Alhambra when he visited Spain in 1936. Escher made four "Circle Limit" drawings of tilings that use hyperbolic geometry. For his woodcut "Circle Limit IV" (1960), Escher prepared a pencil and ink study showing the required geometry. Escher explained that "No single component of all the series, which from infinitely far away rise like rockets perpendicularly from the limit and are at last lost in it, ever reaches the boundary line."
Tessellated designs often appear on textiles, whether woven, stitched in, or printed. Tessellation patterns have been used to design interlocking motifs of patch shapes in quilts.
Tessellations are also a main genre in origami (paper folding), where pleats are used to connect molecules, such as twist folds, together in a repeating fashion. | Tessellation | Wikipedia | 481 | 321671 | https://en.wikipedia.org/wiki/Tessellation | Mathematics | Geometry | null |
In manufacturing
Tessellation is used in manufacturing industry to reduce the wastage of material (yield losses) such as sheet metal when cutting out shapes for objects such as car doors or drink cans.
Tessellation is apparent in the mudcrack-like cracking of thin films – with a degree of self-organisation being observed using micro and nanotechnologies.
In nature
The honeycomb is a well-known example of tessellation in nature with its hexagonal cells.
In botany, the term "tessellate" describes a checkered pattern, for example on a flower petal, tree bark, or fruit. Flowers including the fritillary, and some species of Colchicum, are characteristically tessellate.
Many patterns in nature are formed by cracks in sheets of materials. These patterns can be described by Gilbert tessellations, also known as random crack networks. The Gilbert tessellation is a mathematical model for the formation of mudcracks, needle-like crystals, and similar structures. The model, named after Edgar Gilbert, allows cracks to form starting from being randomly scattered over the plane; each crack propagates in two opposite directions along a line through the initiation point, its slope chosen at random, creating a tessellation of irregular convex polygons. Basaltic lava flows often display columnar jointing as a result of contraction forces causing cracks as the lava cools. The extensive crack networks that develop often produce hexagonal columns of lava. One example of such an array of columns is the Giant's Causeway in Northern Ireland. Tessellated pavement, a characteristic example of which is found at Eaglehawk Neck on the Tasman Peninsula of Tasmania, is a rare sedimentary rock formation where the rock has fractured into rectangular blocks.
Other natural patterns occur in foams; these are packed according to Plateau's laws, which require minimal surfaces. Such foams present a problem in how to pack cells as tightly as possible: in 1887, Lord Kelvin proposed a packing using only one solid, the bitruncated cubic honeycomb with very slightly curved faces. In 1993, Denis Weaire and Robert Phelan proposed the Weaire–Phelan structure, which uses less surface area to separate cells of equal volume than Kelvin's foam.
In puzzles and recreational mathematics | Tessellation | Wikipedia | 467 | 321671 | https://en.wikipedia.org/wiki/Tessellation | Mathematics | Geometry | null |
Tessellations have given rise to many types of tiling puzzle, from traditional jigsaw puzzles (with irregular pieces of wood or cardboard) and the tangram, to more modern puzzles that often have a mathematical basis. For example, polyiamonds and polyominoes are figures of regular triangles and squares, often used in tiling puzzles. Authors such as Henry Dudeney and Martin Gardner have made many uses of tessellation in recreational mathematics. For example, Dudeney invented the hinged dissection, while Gardner wrote about the "rep-tile", a shape that can be dissected into smaller copies of the same shape. Inspired by Gardner's articles in Scientific American, the amateur mathematician Marjorie Rice found four new tessellations with pentagons. Squaring the square is the problem of tiling an integral square (one whose sides have integer length) using only other integral squares. An extension is squaring the plane, tiling it by squares whose sizes are all natural numbers without repetitions; James and Frederick Henle proved that this was possible.
Examples | Tessellation | Wikipedia | 222 | 321671 | https://en.wikipedia.org/wiki/Tessellation | Mathematics | Geometry | null |
Microsoft Paint (commonly known as MS Paint or Paint for short) is a simple raster graphics editor that has been included with all versions of Microsoft Windows. The program opens, modifies and saves image files in Windows bitmap (BMP), JPEG, GIF, PNG, and single-page TIFF formats. The program can be in color mode or two-color black-and-white, but there is no grayscale mode. For its simplicity and wide availability, it rapidly became one of the most used Windows applications, introducing many to painting on a computer for the first time.
In July 2017, Microsoft added Paint to the list of deprecated features of Windows 10 and announced that it had become a free standalone application in Microsoft Store, with Paint 3D as its replacement. However, as a result of public demand from users, Paint has continued to be included with Windows 10 and even Windows 11, with Microsoft instead deprecating Paint 3D. Windows 11 also includes an updated version of Paint in later versions that added, among others updates, a revamped UI and dark mode support.
History
Paint was initially programmed, licensed and adapted from PC Paintbrush made by ZSoft, by Dan McCabe at Microsoft for Windows 1.0, released in late 1985. PC Paintbrush had been previously licensed and published with the Microsoft Mouse DOS drivers from version 4 (circa 1985), to compete with Mouse Systems publishing PCPaint with its own mice in 1984. PC Paintbrush’s inclusion in version 4 of the DOS drivers replaced the previously included Microsoft bitmap color editing application “Doodle,” released in 1983 with the first version of the Microsoft Mouse drivers. With improved functionality over Doodle, it competed successfully against PCPaint and Mouse Systems. Paint included with the first version of Windows, Windows 1.0 in November 1985, had 24 tools and could read and write files in the proprietary "MSP" format drawn in monochrome graphics. Aside from "pencil" and "shape" tools and a brush that draws in 24 "brush shapes and patterns", the toolset also contained two features unique for the time: one the ability to draw Bézier curves and the other that forces lines to be drawn on three angles to create an isometric three-quarter perspective. Paintbrush can only read MSP files; Microsoft has since deprecated the MSP format, repurposing the MSP extension for the Windows Installer Package format. | Microsoft Paint | Wikipedia | 503 | 321796 | https://en.wikipedia.org/wiki/Microsoft%20Paint | Technology | Multimedia_2 | null |
Paint was later superseded by Paintbrush in Windows 3.0, with a redesigned user interface, true color support, and support for the BMP and PCX file formats. This version was also based on a newer licensed version of PC Paintbrush by ZSoft.
Windows 9x
Microsoft shipped an updated version of Paint with Windows 95 and Windows NT 4.0. At this point Microsoft began updating the source code entirely from scratch, and did not license any further code or versions of PC Paintbrush. This version allows saving and loading a custom set of color wells as color palette (.pal) files. This functionality only works correctly if the color depth of images is 16-bits per pixel (bpp) or higher. Later versions of Paint do not support this feature.
In Windows 95–98, Windows 2000 and Windows Me, Paint can open JPEG, GIF and 48-bit (16-bpp) TIF images and save images in JPEG and GIF formats when appropriate graphics filters are installed. Such plug-ins are included with Microsoft Office and Microsoft PhotoDraw. This also allows Paint to use transparent backgrounds. Support for PCX files was dropped. Starting with Windows Me, the canvas size expands automatically when larger images are opened or pasted instead of asking like in previous versions of Windows.
Windows XP and Vista
In Windows XP and later, Paint uses GDI+ and therefore can natively save images as BMP, JPEG, GIF, TIFF and PNG without requiring additional graphics filters. Support for saving and loading custom color palettes was dropped.
In Windows Vista, the toolbar icons were updated and the default color palette was changed. Paint in Windows Vista can undo a change up to 10 times, compared to 3 in previous versions; it also includes a slider for image magnification and a crop function. This version saves in JPEG format by default.
Windows 7 and 8.x | Microsoft Paint | Wikipedia | 392 | 321796 | https://en.wikipedia.org/wiki/Microsoft%20Paint | Technology | Multimedia_2 | null |
The version of Paint in Windows 7 and later features a ribbon in its user interface. It also features "artistic" brushes composed of varying shades of gray and some degree of transparency that give a more realistic result. To add to the realism, the oil and watercolor brushes can only paint for a small distance before the user must re-click (this gives the illusion that the paintbrush has run out of paint). In addition, Paint can now undo up to 50 subsequent changes. It also has anti-aliased shapes, which can be resized freely until they are rasterized when another tool is selected. This version supports viewing (but not saving) transparent PNG and ICO file formats and saves files in the .png file format by default.
Text can now be pasted into text boxes that don't have enough room to display the text. A text box can then be enlarged or reshaped appropriately to fit the text if desired. Previous versions of Paint would display an error message if a user tried to paste more text than there was room for.
The Windows 8 version of Paint mostly corrects a long-standing defect from previous versions involving the inability to scroll the window when editing in Zoom view over 100%. However, when the user inserts text in Zoom view, they cannot move the text beyond the zoomed viewport while the text window is in edit mode with either the mouse or keyboard.
Windows 10
In the April 2017 "Creators Update" for Windows 10, Microsoft released Paint 3D alongside Paint. In addition to the traditional two-dimensional drawing tools, Paint 3D can import and manipulate three-dimensional models. Three months later, on July 23, 2017, Microsoft added Paint to the list of deprecated Windows features. The next day, in the wake of "an incredible outpouring of support and nostalgia", Microsoft clarified that Paint would become a free app on Microsoft Store, even though Paint 3D offers the same functionality.
Despite the deprecation, Paint continues to be a part of all versions of Windows 10 up to version 22H2. The closest that Microsoft ever got to enacting said decision was adding a removal notice to Paint's user interface in Windows 10 versions 1803 and 1809. | Microsoft Paint | Wikipedia | 452 | 321796 | https://en.wikipedia.org/wiki/Microsoft%20Paint | Technology | Multimedia_2 | null |
In March 2021, with the release of Windows 10 Insider build 21332 to the Dev Channel, Microsoft removed Paint 3D from clean installations of the build, in addition to the 3D Objects app. In April 2021, Microsoft released Windows 10 Insider build 21354, which made Paint (along with Snipping Tool) updatable from the Microsoft Store. It had also been moved from the Windows Accessories folder of the Start menu to its own section.
Windows 11
In August 2021, Microsoft teased an updated version of Paint for Windows 11, featuring a refreshed user interface (UI), improved font picker, and a dark theme. This newly updated version of Paint was released with Windows 11 Insider build 22468 in September 2021, and was officially released as part of the Windows 11 2022 Update in September 2022. In September 2023, Microsoft released an update that added layers, support for transparent PNG files, AI art generator and other AI tools and a background removal tool.
Despite new features being added into Paint in Windows 11, some older features have disappeared. Paint in Windows 11 also automatically anti-aliases all fonts that are inputted using the "Text" feature, even those that are aliased by design, such as Courier New. Smaller images are also harder to manipulate and work with in newer versions of Paint, as it automatically blurs images when they are resized or re-copied. This is especially noticeable when working with video game sprites and pixel art. These issues are due to interpolation algorithms that Paint is using, according to Microsoft.
Features
Paint has a few functions not mentioned in the help file: a stamp mode, trail mode, regular shapes, and moving pictures. For the stamp mode, the user can select a part of the image, hold the key, and move it to another part of the canvas. This, instead of cutting the piece out, creates a copy of it. The process can be repeated as many times as desired, as long as the key is held down. The trail mode works exactly the same, but it uses the instead of the key.
It is also possible to thicken or thin a line either before or simultaneously while it is being drawn via (NumPad only) or (NumPad only). | Microsoft Paint | Wikipedia | 461 | 321796 | https://en.wikipedia.org/wiki/Microsoft%20Paint | Technology | Multimedia_2 | null |
To crop whitespace or eliminate parts of a graphic, the blue handle in the lower right corner can be dragged to increase canvas size or crop a graphic. Users can also draw perfect shapes (which have a width equal to the height) using any shape tool by holding down the while dragging.
Older versions of Paint, such as the one bundled with Windows 3.1, featured a color-replace brush, which replaced a single color underneath the brush with another without affecting the rest of the image. In later versions of Paint, the color erase brush was removed as an option, however it can still be simulated by selecting the color to be replaced as the primary color, and the one it is replaced with as the secondary color, and then right-click dragging the erase tool.
Support for indexed palettes
By default, almost all versions of Paint are generally unable to properly downgrade created images to indexed palettes using fewer than 24 bits per pixel. When saving an image in a format that uses indexed palettes with fewer than 24 bits per pixel, a warning message appears about the loss of quality. Paint does not utilize binary, color or grayscale dithering or palette optimization, and the image will be saved with usually irreversibly scrambled colors.
Paint is nonetheless able to correctly load and save indexed palettes in any of the supported formats if an image is opened as an 8-bit or otherwise indexed palette image. In that case, the image's palette is preserved when saving. However, there is no way to see the actual palette; color choices for brushes, text, and erasers as well as user-defined colors will be limited to the closest available color in the indexed palette. | Microsoft Paint | Wikipedia | 342 | 321796 | https://en.wikipedia.org/wiki/Microsoft%20Paint | Technology | Multimedia_2 | null |
The fibula (: fibulae or fibulas) or calf bone is a leg bone on the lateral side of the tibia, to which it is connected above and below. It is the smaller of the two bones and, in proportion to its length, the most slender of all the long bones. Its upper extremity is small, placed toward the back of the head of the tibia, below the knee joint and excluded from the formation of this joint. Its lower extremity inclines a little forward, so as to be on a plane anterior to that of the upper end; it projects below the tibia and forms the lateral part of the ankle joint.
Structure
The bone has the following components:
Lateral malleolus
Interosseous membrane connecting the fibula to the tibia, forming a syndesmosis joint
The superior tibiofibular articulation is an arthrodial joint between the lateral condyle of the tibia and the head of the fibula.
The inferior tibiofibular articulation (tibiofibular syndesmosis) is formed by the rough, convex surface of the medial side of the lower end of the fibula, and a rough concave surface on the lateral side of the tibia.
Blood supply
The blood supply is important for planning free tissue transfer because the fibula is commonly used to reconstruct the mandible. The shaft is supplied in its middle third by a large nutrient vessel from the fibular artery. It is also perfused from its periosteum which receives many small branches from the fibular artery. The proximal head and the epiphysis are supplied by a branch of the anterior tibial artery. In harvesting the bone the middle third is always taken and the ends preserved (4 cm proximally and 6 cm distally)
Development
The fibula is ossified from three centers, one for the shaft, and one for either end. Ossification begins in the body about the eighth week of fetal life, and extends toward the extremities. At birth the ends are cartilaginous.
Ossification commences in the lower end in the second year, and in the upper about the fourth year. The lower epiphysis, the first to ossify, unites with the body about the twentieth year; the upper epiphysis joins about the twenty-fifth year. | Fibula | Wikipedia | 497 | 321814 | https://en.wikipedia.org/wiki/Fibula | Biology and health sciences | Skeletal system | Biology |
Head
The upper extremity or head of the fibula is of an irregular quadrate form, presenting above a flattened articular surface, directed upward, forward, and medialward, for articulation with a corresponding surface on the lateral condyle of the tibia.
On the lateral side is a thick and rough prominence continued behind into a pointed eminence, the apex (styloid process), which projects upward from the posterior part of the head.
The prominence, at its upper and lateral part, gives attachment to the tendon of the biceps femoris and to the fibular collateral ligament of the knee-joint, the ligament dividing the tendon into two parts.
The remaining part of the circumference of the head is rough, for the attachment of muscles and ligaments.
It presents in front a tubercle for the origin of the upper and anterior fibers of the peroneus longus, and a surface for the attachment of the anterior ligament of the head; and behind, another tubercle, for the attachment of the posterior ligament of the head and the origin of the upper fibers of the soleus.
Body
The body of the fibula presents four borders - the antero-lateral, the antero-medial, the postero-lateral, and the postero-medial; and four surfaces - anterior, posterior, medial, and lateral.
Borders
The antero-lateral border begins above in front of the head, runs vertically downward to a little below the middle of the bone, and then curving somewhat lateralward, bifurcates so as to embrace a triangular subcutaneous surface immediately above the lateral malleolus. This border gives attachment to an intermuscular septum, which separates the extensor muscles on the anterior surface of the leg from the peronaei longus and brevis on the lateral surface.
The antero-medial border, or interosseous crest, is situated close to the medial side of the preceding, and runs nearly parallel with it in the upper third of its extent, but diverges from it in the lower two-thirds. It begins above just beneath the head of the bone (sometimes it is quite indistinct for about 2.5 cm. below the head), and ends at the apex of a rough triangular surface immediately above the articular facet of the lateral malleolus. It serves for the attachment of the interosseous membrane, which separates the extensor muscles in front from the flexor muscles behind. | Fibula | Wikipedia | 512 | 321814 | https://en.wikipedia.org/wiki/Fibula | Biology and health sciences | Skeletal system | Biology |
The postero-lateral border is prominent; it begins above at the apex, and ends below in the posterior border of the lateral malleolus. It is directed lateralward above, backward in the middle of its course, backward, and a little medialward below, and gives attachment to an aponeurosis which separates the peronaei on the lateral surface from the flexor muscles on the posterior surface.
The postero-medial border, sometimes called the oblique line, begins above at the medial side of the head, and ends by becoming continuous with the interosseous crest at the lower fourth of the bone. It is well-marked and prominent at the upper and middle parts of the bone. It gives attachment to an aponeurosis which separates the tibialis posterior from the soleus and flexor hallucis longus.
Surfaces
The anterior surface is the interval between the antero-lateral and antero-medial borders. It is extremely narrow and flat in the upper third of its extent; broader and grooved longitudinally in its lower third; it serves for the origin of three muscles: the extensor digitorum longus, extensor hallucis longus, and peroneus tertius.
The posterior surface is the space included between the postero-lateral and the postero-medial borders; it is continuous below with the triangular area above the articular surface of the lateral malleolus; it is directed backward above, backward and medialward at its middle, directly medialward below. Its upper third is rough, for the origin of the soleus; its lower part presents a triangular surface, connected to the tibia by a strong interosseous ligament; the intervening part of the surface is covered by the fibers of origin of the flexor hallucis longus. Near the middle of this surface is the nutrient foramen, which is directed downward.
The medial surface is the interval included between the antero-medial and the postero-medial borders. It is grooved for the origin of the tibialis posterior.
The lateral surface is the space between the antero-lateral and postero-lateral borders. It is broad, and often deeply grooved; it is directed lateralward in the upper two-thirds of its course, backward in the lower third, where it is continuous with the posterior border of the lateral malleolus. This surface gives origin to the peronaei longus and brevis. | Fibula | Wikipedia | 501 | 321814 | https://en.wikipedia.org/wiki/Fibula | Biology and health sciences | Skeletal system | Biology |
Function
The fibula does not carry any significant load (weight) of the body. It extends past the lower end of the tibia and forms the outer part of the ankle providing stability to this joint. It has grooves(a depression) for certain ligaments which gives them leverage and multiplies the muscle force. It provides attachment points for the following muscles:
Clinical significance
As much of the fibula can be removed without it impacting an individual's ability to walk, the fibula is utilised as a source of bone material in fibular free flap surgeries.
Fractures
The most common type of fibula fracture is located at the distal end of the bone, and is classified as ankle fracture. In the Danis–Weber classification it has three categories:
Type A: Fracture of the lateral malleolus, distal to the syndesmosis (the connection between the distal ends of the tibia and fibula).
Type B: Fracture of the fibula at the level of the syndesmosis
Type C: Fracture of the fibula proximal to the syndesmosis.
A Maisonneuve fracture is a spiral fracture of the proximal third of the fibula associated with a tear of the distal tibiofibular syndesmosis and the interosseous membrane. There is an associated fracture of the medial malleolus or rupture of the deep deltoid ligament.
An avulsion fracture of the head of the fibula refers to the fracture of the fibular head because of a sudden contraction of the biceps femoris muscle that pulls its site of attachment on the bone. The attachment of the biceps femoris tendon on the fibular head is closely related to the lateral collateral ligament of the knee. Therefore, this ligament is prone to injury in this type of avulsion fracture.
History
Etymology
The word fibula can be dated back to c. 1670. It derives from Latin fībula, which describes a clasp or brooch – see fibula (brooch) – and was first used in English for the smaller bone in the lower leg c. 1706. The bone was so called because it resembles a clasp like a modern safety pin.
The adjective peroneal referring to the fibula bone or its surrounding structures derives from : perónē, the Ancient Greek word for a clasp. | Fibula | Wikipedia | 473 | 321814 | https://en.wikipedia.org/wiki/Fibula | Biology and health sciences | Skeletal system | Biology |
Other animals
Because the fibula bears relatively little weight in comparison with the tibia, it is typically narrower in all but the most primitive tetrapods. In many animals, it still articulates with the posterior part of the lower extremity of the femur, but this feature is frequently lost (as it is in humans). In some animals, the reduction of the fibula has proceeded even further than it has in humans, with the loss of the tarsal articulation, and, in extreme cases (such as the horse), partial fusion with the tibia. | Fibula | Wikipedia | 119 | 321814 | https://en.wikipedia.org/wiki/Fibula | Biology and health sciences | Skeletal system | Biology |
Coding theory is the study of the properties of codes and their respective fitness for specific applications. Codes are used for data compression, cryptography, error detection and correction, data transmission and data storage. Codes are studied by various scientific disciplines—such as information theory, electrical engineering, mathematics, linguistics, and computer science—for the purpose of designing efficient and reliable data transmission methods. This typically involves the removal of redundancy and the correction or detection of errors in the transmitted data.
There are four types of coding:
Data compression (or source coding)
Error control (or channel coding)
Cryptographic coding
Line coding
Data compression attempts to remove unwanted redundancy from the data from a source in order to transmit it more efficiently. For example, DEFLATE data compression makes files smaller, for purposes such as to reduce Internet traffic. Data compression and error correction may be studied in combination.
Error correction adds useful redundancy to the data from a source to make the transmission more robust to disturbances present on the transmission channel. The ordinary user may not be aware of many applications using error correction. A typical music compact disc (CD) uses the Reed–Solomon code to correct for scratches and dust. In this application the transmission channel is the CD itself. Cell phones also use coding techniques to correct for the fading and noise of high frequency radio transmission. Data modems, telephone transmissions, and the NASA Deep Space Network all employ channel coding techniques to get the bits through, for example the turbo code and LDPC codes.
History of coding theory
In 1948, Claude Shannon published "A Mathematical Theory of Communication", an article in two parts in the July and October issues of the Bell System Technical Journal. This work focuses on the problem of how best to encode the information a sender wants to transmit. In this fundamental work he used tools in probability theory, developed by Norbert Wiener, which were in their nascent stages of being applied to communication theory at that time. Shannon developed information entropy as a measure for the uncertainty in a message while essentially inventing the field of information theory.
The binary Golay code was developed in 1949. It is an error-correcting code capable of correcting up to three errors in each 24-bit word, and detecting a fourth.
Richard Hamming won the Turing Award in 1968 for his work at Bell Labs in numerical methods, automatic coding systems, and error-detecting and error-correcting codes. He invented the concepts known as Hamming codes, Hamming windows, Hamming numbers, and Hamming distance. | Coding theory | Wikipedia | 511 | 321869 | https://en.wikipedia.org/wiki/Coding%20theory | Mathematics | Discrete mathematics | null |
In 1972, Nasir Ahmed proposed the discrete cosine transform (DCT), which he developed with T. Natarajan and K. R. Rao in 1973. The DCT is the most widely used lossy compression algorithm, the basis for multimedia formats such as JPEG, MPEG and MP3.
Source coding
The aim of source coding is to take the source data and make it smaller.
Definition
Data can be seen as a random variable , where appears with probability .
Data are encoded by strings (words) over an alphabet .
A code is a function
(or if the empty string is not part of the alphabet).
is the code word associated with .
Length of the code word is written as
Expected length of a code is
The concatenation of code words .
The code word of the empty string is the empty string itself:
Properties
is non-singular if injective.
is uniquely decodable if injective.
is instantaneous if is not a proper prefix of (and vice versa).
Principle
Entropy of a source is the measure of information. Basically, source codes try to reduce the redundancy present in the source, and represent the source with fewer bits that carry more information.
Data compression which explicitly tries to minimize the average length of messages according to a particular assumed probability model is called entropy encoding.
Various techniques used by source coding schemes try to achieve the limit of entropy of the source. C(x) ≥ H(x), where H(x) is entropy of source (bitrate), and C(x) is the bitrate after compression. In particular, no source coding scheme can be better than the entropy of the source.
Example
Facsimile transmission uses a simple run length code. Source coding removes all data superfluous to the need of the transmitter, decreasing the bandwidth required for transmission.
Channel coding
The purpose of channel coding theory is to find codes which transmit quickly, contain many valid code words and can correct or at least detect many errors. While not mutually exclusive, performance in these areas is a trade-off. So, different codes are optimal for different applications. The needed properties of this code mainly depend on the probability of errors happening during transmission. In a typical CD, the impairment is mainly dust or scratches.
CDs use cross-interleaved Reed–Solomon coding to spread the data out over the disk. | Coding theory | Wikipedia | 480 | 321869 | https://en.wikipedia.org/wiki/Coding%20theory | Mathematics | Discrete mathematics | null |
Although not a very good code, a simple repeat code can serve as an understandable example. Suppose we take a block of data bits (representing sound) and send it three times. At the receiver we will examine the three repetitions bit by bit and take a majority vote. The twist on this is that we do not merely send the bits in order. We interleave them. The block of data bits is first divided into 4 smaller blocks. Then we cycle through the block and send one bit from the first, then the second, etc. This is done three times to spread the data out over the surface of the disk. In the context of the simple repeat code, this may not appear effective. However, there are more powerful codes known which are very effective at correcting the "burst" error of a scratch or a dust spot when this interleaving technique is used.
Other codes are more appropriate for different applications. Deep space communications are limited by the thermal noise of the receiver which is more of a continuous nature than a bursty nature. Likewise, narrowband modems are limited by the noise, present in the telephone network and also modeled better as a continuous disturbance. Cell phones are subject to rapid fading. The high frequencies used can cause rapid fading of the signal even if the receiver is moved a few inches. Again there are a class of channel codes that are designed to combat fading.
Linear codes
The term algebraic coding theory denotes the sub-field of coding theory where the properties of codes are expressed in algebraic terms and then further researched.
Algebraic coding theory is basically divided into two major types of codes:
Linear block codes
Convolutional codes
It analyzes the following three properties of a code – mainly:
Code word length
Total number of valid code words
The minimum distance between two valid code words, using mainly the Hamming distance, sometimes also other distances like the Lee distance
Linear block codes
Linear block codes have the property of linearity, i.e. the sum of any two codewords is also a code word, and they are applied to the source bits in blocks, hence the name linear block codes. There are block codes that are not linear, but it is difficult to prove that a code is a good one without this property.
Linear block codes are summarized by their symbol alphabets (e.g., binary or ternary) and parameters (n,m,dmin) where | Coding theory | Wikipedia | 487 | 321869 | https://en.wikipedia.org/wiki/Coding%20theory | Mathematics | Discrete mathematics | null |
n is the length of the codeword, in symbols,
m is the number of source symbols that will be used for encoding at once,
dmin is the minimum hamming distance for the code.
There are many types of linear block codes, such as
Cyclic codes (e.g., Hamming codes)
Repetition codes
Parity codes
Polynomial codes (e.g., BCH codes)
Reed–Solomon codes
Algebraic geometric codes
Reed–Muller codes
Perfect codes
Locally recoverable code
Block codes are tied to the sphere packing problem, which has received some attention over the years. In two dimensions, it is easy to visualize. Take a bunch of pennies flat on the table and push them together. The result is a hexagon pattern like a bee's nest. But block codes rely on more dimensions which cannot easily be visualized. The powerful (24,12) Golay code used in deep space communications uses 24 dimensions. If used as a binary code (which it usually is) the dimensions refer to the length of the codeword as defined above.
The theory of coding uses the N-dimensional sphere model. For example, how many pennies can be packed into a circle on a tabletop, or in 3 dimensions, how many marbles can be packed into a globe. Other considerations enter the choice of a code. For example, hexagon packing into the constraint of a rectangular box will leave empty space at the corners. As the dimensions get larger, the percentage of empty space grows smaller. But at certain dimensions, the packing uses all the space and these codes are the so-called "perfect" codes. The only nontrivial and useful perfect codes are the distance-3 Hamming codes with parameters satisfying (2r – 1, 2r – 1 – r, 3), and the [23,12,7] binary and [11,6,5] ternary Golay codes. | Coding theory | Wikipedia | 391 | 321869 | https://en.wikipedia.org/wiki/Coding%20theory | Mathematics | Discrete mathematics | null |
Another code property is the number of neighbors that a single codeword may have.
Again, consider pennies as an example. First we pack the pennies in a rectangular grid. Each penny will have 4 near neighbors (and 4 at the corners which are farther away). In a hexagon, each penny will have 6 near neighbors. When we increase the dimensions, the number of near neighbors increases very rapidly. The result is the number of ways for noise to make the receiver choose a neighbor (hence an error) grows as well. This is a fundamental limitation of block codes, and indeed all codes. It may be harder to cause an error to a single neighbor, but the number of neighbors can be large enough so the total error probability actually suffers.
Properties of linear block codes are used in many applications. For example, the syndrome-coset uniqueness property of linear block codes is used in trellis shaping, one of the best-known shaping codes.
Convolutional codes
The idea behind a convolutional code is to make every codeword symbol be the weighted sum of the various input message symbols. This is like convolution used in LTI systems to find the output of a system, when you know the input and impulse response.
So we generally find the output of the system convolutional encoder, which is the convolution of the input bit, against the states of the convolution encoder, registers.
Fundamentally, convolutional codes do not offer more protection against noise than an equivalent block code. In many cases, they generally offer greater simplicity of implementation over a block code of equal power. The encoder is usually a simple circuit which has state memory and some feedback logic, normally XOR gates. The decoder can be implemented in software or firmware.
The Viterbi algorithm is the optimum algorithm used to decode convolutional codes. There are simplifications to reduce the computational load. They rely on searching only the most likely paths. Although not optimum, they have generally been found to give good results in low noise environments.
Convolutional codes are used in voiceband modems (V.32, V.17, V.34) and in GSM mobile phones, as well as satellite and military communication devices.
Cryptographic coding | Coding theory | Wikipedia | 485 | 321869 | https://en.wikipedia.org/wiki/Coding%20theory | Mathematics | Discrete mathematics | null |
Cryptography or cryptographic coding is the practice and study of techniques for secure communication in the presence of third parties (called adversaries). More generally, it is about constructing and analyzing protocols that block adversaries; various aspects in information security such as data confidentiality, data integrity, authentication, and non-repudiation are central to modern cryptography. Modern cryptography exists at the intersection of the disciplines of mathematics, computer science, and electrical engineering. Applications of cryptography include ATM cards, computer passwords, and electronic commerce.
Cryptography prior to the modern age was effectively synonymous with encryption, the conversion of information from a readable state to apparent nonsense. The originator of an encrypted message shared the decoding technique needed to recover the original information only with intended recipients, thereby precluding unwanted persons from doing the same. Since World War I and the advent of the computer, the methods used to carry out cryptology have become increasingly complex and its application more widespread.
Modern cryptography is heavily based on mathematical theory and computer science practice; cryptographic algorithms are designed around computational hardness assumptions, making such algorithms hard to break in practice by any adversary. It is theoretically possible to break such a system, but it is infeasible to do so by any known practical means. These schemes are therefore termed computationally secure; theoretical advances, e.g., improvements in integer factorization algorithms, and faster computing technology require these solutions to be continually adapted. There exist information-theoretically secure schemes that cannot be broken even with unlimited computing power—an example is the one-time pad—but these schemes are more difficult to implement than the best theoretically breakable but computationally secure mechanisms.
Line coding
A line code (also called digital baseband modulation or digital baseband transmission method) is a code chosen for use within a communications system for baseband transmission purposes. Line coding is often used for digital data transport.
Line coding consists of representing the digital signal to be transported by an amplitude- and time-discrete signal that is optimally tuned for the specific properties of the physical channel (and of the receiving equipment). The waveform pattern of voltage or current used to represent the 1s and 0s of a digital data on a transmission link is called line encoding. The common types of line encoding are unipolar, polar, bipolar, and Manchester encoding.
Other applications of coding theory | Coding theory | Wikipedia | 486 | 321869 | https://en.wikipedia.org/wiki/Coding%20theory | Mathematics | Discrete mathematics | null |
Another concern of coding theory is designing codes that help synchronization. A code may be designed so that a phase shift can be easily detected and corrected and that multiple signals can be sent on the same channel.
Another application of codes, used in some mobile phone systems, is code-division multiple access (CDMA). Each phone is assigned a code sequence that is approximately uncorrelated with the codes of other phones. When transmitting, the code word is used to modulate the data bits representing the voice message. At the receiver, a demodulation process is performed to recover the data. The properties of this class of codes allow many users (with different codes) to use the same radio channel at the same time. To the receiver, the signals of other users will appear to the demodulator only as a low-level noise.
Another general class of codes are the automatic repeat-request (ARQ) codes. In these codes the sender adds redundancy to each message for error checking, usually by adding check bits. If the check bits are not consistent with the rest of the message when it arrives, the receiver will ask the sender to retransmit the message. All but the simplest wide area network protocols use ARQ. Common protocols include SDLC (IBM), TCP (Internet), X.25 (International) and many others. There is an extensive field of research on this topic because of the problem of matching a rejected packet against a new packet. Is it a new one or is it a retransmission? Typically numbering schemes are used, as in TCP.
Group testing
Group testing uses codes in a different way. Consider a large group of items in which a very few are different in a particular way (e.g., defective products or infected test subjects). The idea of group testing is to determine which items are "different" by using as few tests as possible. The origin of the problem has its roots in the Second World War when the United States Army Air Forces needed to test its soldiers for syphilis.
Analog coding
Information is encoded analogously in the neural networks of brains, in analog signal processing, and analog electronics. Aspects of analog coding include analog error correction,
analog data compression and analog encryption. | Coding theory | Wikipedia | 464 | 321869 | https://en.wikipedia.org/wiki/Coding%20theory | Mathematics | Discrete mathematics | null |
Neural coding
Neural coding is a neuroscience-related field concerned with how sensory and other information is represented in the brain by networks of neurons. The main goal of studying neural coding is to characterize the relationship between the stimulus and the individual or ensemble neuronal responses and the relationship among electrical activity of the neurons in the ensemble. It is thought that neurons can encode both digital and analog information, and that neurons follow the principles of information theory and compress information, and detect and correct
errors in the signals that are sent throughout the brain and wider nervous system. | Coding theory | Wikipedia | 112 | 321869 | https://en.wikipedia.org/wiki/Coding%20theory | Mathematics | Discrete mathematics | null |
Honeypot ants, also called honey ants, are ants which have specialized workers (repletes, plerergates, or rotunds) that consume large amounts of food to the point that their abdomens swell enormously. Other ants then extract nourishment from them, through the process of trophallaxis. They function as living larders. Honeypot ants belong to any of several genera, including Myrmecocystus and Camponotus. They were first documented in 1881 by Henry C. McCook, and described further in 1908 by William Morton Wheeler.
Behavior
Many insects, notably honey bees and some wasps, collect and store liquid for use at a later date. However, these insects store their food within their nest or in combs. Honey ants are unique in using their own bodies as living storage, used later by their fellow ants when food is otherwise scarce. When the liquid stored inside a honeypot ant is needed, the worker ants stroke the antennae of the honeypot ant, causing the honeypot ant to regurgitate the stored liquid from its crop.
Anatomy
The abdomen of species like Camponotus inflatus consists of hard dorsal sclerites (stiff plates) connected by a softer, more flexible arthrodial membrane. When the abdomen is empty, the arthrodial membrane is folded and the sclerites overlap, but when the abdomen fills the arthrodial membrane becomes fully stretched, leaving the sclerites widely separated.
Ecology
Myrmecocystus nests are found in a variety of arid or semiarid environments. Some species live in extremely hot deserts, others reside in transitional habitats, and still other species can be found in woodlands which are somewhat cool but still very dry for a large part of the year. For instance, the well-studied Myrmecocystus mexicanus resides in the arid and semiarid habitats of the southwestern United States. Sterile workers in this species act as plerergates or repletes during times of food scarcity. When the plerergates are fully engorged, they become immobile and hang from the ceilings of the underground nests. Other workers drain them of their liquid food stores to feed the rest of the colony. Plerergates can live anywhere in the nest, but in the wild, they are found deep underground, unable to move, swollen to the size of grapes. | Honeypot ant | Wikipedia | 490 | 321940 | https://en.wikipedia.org/wiki/Honeypot%20ant | Biology and health sciences | Hymenoptera | Animals |
In Camponotus inflatus in Australia, repletes formed 49% (516 ants) of a colony of 1063 ants, and 46% (1835 ants) of a colony of 4019 ants. The smaller colony contained six wingless queens. The larger colony had 66 chambers containing repletes, with a maximum of 191 repletes in a chamber. The largest replete was 15 millimetres long and had a mass of 1.4 grams. The nest had a maximum depth of 1.7 metres, and tunnels stretched 2.4 metres from the nest entrance. The workers went out foraging during daylight to collect nectar from Mulga nectaries, and meat from the carcass of a Tiliqua blue-tongued lizard.
Genera
Honeypot food storage has been adopted in several seasonally active ant genera:
Camponotus of Australia
Cataglyphis of North Africa
Leptomyrmex of Melanesia
Melophorus of Australia
Myrmecocystus of North America.
Plagiolepis of South Africa
Prenolepis of North America
In human culture
Honeypot ants such as Melophorus bagoti and Camponotus spp. are edible insects and form an occasional part of the diet of various Indigenous Australians. These people scrape the surface to locate the ants' vertical tunnels, and then dig as much as two metres deep to find the honeypots. Papunya, in Australia's Northern Territory, is named after a honey ant creation story, or Dreaming, which belongs to the people there, such as the Warlpiri. The honey ants were celebrated in the Western Desert Art Movement's The Honey Ant Mural, painted in 1971.
Indigenous medicinal use
Indigenous Australians from the Tjupan language group use honeypot ant honey to treat sore throats, and as a topical ointment to treat skin infections. A Sydney University study has investigated the efficacy of honey from Camponotus inflatus, and found it effective against the bacterium Staphylococcus aureus, and the fungi Aspergillus and Cryptococcus. The antimicrobial mechanism is significantly different to that of Mānuka honey. | Honeypot ant | Wikipedia | 441 | 321940 | https://en.wikipedia.org/wiki/Honeypot%20ant | Biology and health sciences | Hymenoptera | Animals |
The M4 carbine (officially Carbine, Caliber 5.56 mm, M4) is a 5.56×45mm NATO assault rifle developed in the United States during the 1980s. It is a shortened version of the M16A2 assault rifle. The M4 is extensively used by the US military, with decisions to largely replace the M16 rifle in US Army (starting 2010) and US Marine Corps (starting 2016) combat units as the primary infantry weapon and service rifle. The M4 has been adopted by over 60 countries worldwide, and has been described as "one of the defining firearms of the 21st century".
Since its adoption in 1994, the M4 has undergone over 90 modifications to improve the weapon's adaptability, ergonomics and modularity, including: the M4A1, which strengthened the barrel and replaced the burst-fire option with a fully automatic option; the SOPMOD, an accessory kit containing optical attachments; and the underbarrel weapons such as M203 and M320 grenade launchers to the Masterkey and M26-MASS shotguns.
In April 2022, the U.S. Army selected the XM7 rifle, a variant of SIG MCX Spear, as the winner of the Next Generation Squad Weapon Program to replace the M16/M4.
History
Development of the M4
Following the military adoption of the Armalite AR-15 as the M16 rifle, carbine variants were also adopted for CQC operations, the first of which was the CAR-15 family of weapons, which was used in the Vietnam War. However, these rifles had design issues, as the barrel length was halved to , which upset the ballistics, reducing its range and accuracy and leading to considerable muzzle flash and blast, meaning that a large flash suppressor had to be fitted. | M4 carbine | Wikipedia | 376 | 321957 | https://en.wikipedia.org/wiki/M4%20carbine | Technology | Specific firearms | null |
In 1982, the U.S. Government requested Colt to make a carbine version of the M16A2. At the time, the Colt M16A2 was the Colt 645, also known as the M16A1E1. Later that year, the U.S. Army Armament Munitions Chemical Command helped Colt develop a new variant of the XM177E2, and the U.S. Army redesignated the XM177E2 to the XM4 Carbine, giving the name as the successor to the M3 carbine. The carbine used the same upper and lower receiver as the M16A1, and fires the M855 cartridge along with the older M193 cartridges. In 1983, the 9th Infantry Division requested a Quick Reaction Program (QRP) for a 5.56mm carbine to replace the M1 carbine and M3 submachine gun in service. The XM4 was tested by the Army's Armament Research and Development Center (ARDC) in June 1983. Later, the gun was updated with improved furniture, and a barrel with rifling of 1 turn in . The ARDC recommended additional commonality with the M16A2 rifle, as well as lengthening the barrel to . In January 1984, the U.S. Army revised the QRP, and a month later, it formally approved development of the new carbine.
In June 1985, the Picatinny Arsenal was given a contract to produce 40 prototypes of the XM4. Initially a joint program between the Army and Marines, in 1986 the Army withdrew their funding. The XM4 was finished in 1987, and the Marines adopted 892 for that fiscal year, with the designation "carbine, 5.56mm, M4". Owing to experience from the 1991 Gulf War, the Army gave Colt its first production contracts for M4 carbines in May and July 1993, and M4A1 carbines for United States Special Operations Command (SOCOM) operators in February 1994. | M4 carbine | Wikipedia | 413 | 321957 | https://en.wikipedia.org/wiki/M4%20carbine | Technology | Specific firearms | null |
Interest in the M4 carbine was accelerated after the Battle of Mogadishu (1993), in which Rangers complained that their M16 rifles were "unwieldy", whereas members of Delta Force in the same battle, equipped with the CAR-15, had no such complaints. The M4 carbine first saw action in the hands of U.S. troops deployed to Kosovo in 1999 in support of the NATO-led Kosovo Force. It would subsequently be used heavily by U.S. forces during the war on terror, including in Operation Enduring Freedom and the Iraq War. In the Army, the M4 had largely replaced M16A2s as the primary weapon of forward deployed personnel by 2005. The M4 carbine also replaced most submachine guns and selected handguns in U.S. military service, as it fires more effective rifle ammunition that offers superior stopping power and is better able to penetrate modern body armor.
In 2007, the USMC ordered its officers (up to the rank of lieutenant colonel) and staff non-commissioned officers to carry the M4 carbine instead of the M9 handgun. This is in keeping with the Marine Corps doctrine, "Every Marine a rifleman." The Marine Corps, however, chose the full-sized M16A4 over the M4 as its standard infantry rifle. United States Navy corpsmen E5 and below are also issued M4s instead of the M9. While ordinary riflemen in the Marine Corps were armed with M16A4s, M4s were fielded by troops in positions where a full-length rifle would be too bulky, including vehicle operators, fireteam and squad leaders. As of 2013, the U.S. Marine Corps had 80,000 M4 carbines in their inventory. | M4 carbine | Wikipedia | 366 | 321957 | https://en.wikipedia.org/wiki/M4%20carbine | Technology | Specific firearms | null |
By July 2015, major Marine Corps commands were endorsing switching to the M4 over the M16A4 as the standard infantry rifle, just as the Army had done. This is because of the carbine's lighter weight, compact length, and ability to address modern combat situations that happen mostly within close quarters; if a squad needs to engage at longer ranges, the M27 Infantry Automatic Rifle can be used as a designated marksman rifle. Approval of the change would move the M16 to support personnel, while armories already had the 17,000 M4s in the inventory needed to outfit all infantrymen who needed one. In October 2015, Commandant Robert Neller formally approved of making the M4 carbine the primary weapon for all infantry battalions, security forces, and supporting schools in the USMC. The switch was to be completed by September 2016. In December 2017, the Marine Corps revealed a decision to equip every Marine in an infantry squad with the M27, while the M4 would be retained for leadership billets at the platoon level and above. MARSOC also retains the M4, as its shorter barrel is more suited to how they operate in confined spaces.
Improved M4
In 2009, the U.S. Army took complete ownership of the M4 design. This allowed companies other than Colt to compete with their own M4 designs. The Army planned on fielding the last of its M4 requirement in 2010. In October 2009, Army weapons officials proposed a series of changes to the M4 to Congress. Requested changes included an electronic round counter that records the number of shots fired, a heavier "SOCOM barrel", and possibly replacing the Stoner expanding gas system with a gas piston system. The heavier "SOCOM barrel" was first issued to special forces operators in the early 2000s to enable greater sustained automatic fire in certain immediate-action drills, although SOCOM itself would eventually return to the standard "government profile" barrel in its subsequent M4 improvement programs.
The benefits of these changes, however, have come under scrutiny from both the military and civilian firearms community. According to a PDF detailing the M4 Carbine improvement plans released by PEO Soldier, the direct impingement system would be replaced only after reviews were done comparing the direct impingement system to commercial gas piston operating system to find out and use the best available operating system in the U.S. Army's improved M4A1. | M4 carbine | Wikipedia | 493 | 321957 | https://en.wikipedia.org/wiki/M4%20carbine | Technology | Specific firearms | null |
In September 2010, the Army announced it would buy 12,000 M4A1s from Colt Firearms by the end of 2010, and would order 25,000 more M4A1s by early 2011. Additionally, the service branch planned to buy 12,000 M4A1 conversion kits in early 2011 and bought 65,000 more later that year. Eventually, the Army would upgrade all of its M4s to M4A1s, although the Marine Corps would largely abstain from the effort. Conversion of M4s to the M4A1 in the Army began in 2011, as part of the Product Improvement Program, which included the conversion of 300,000 M4 carbines to the M4A1. The 101st Airborne Division began fielding newly built M4A1s in 2012, and the U.S. 1st Infantry Division became the first unit to convert their M4s to M4A1-standard in May 2014. Upgrades included the heavier SOCOM barrel to better dissipate heat from sustained automatic firing, the full-auto trigger group with a more consistent trigger pull than the burst group's to enable better semi-automatic accuracy, and the ambidextrous selector lever for easier use with left-handed shooters. The M4-M4A1 conversion increases weapon weight from to , counting a back-up iron sight, forward pistol grip, empty magazine, and sling. Each carbine upgrade costs $240 per rifle, for a total cost of $120 million for half a million conversions. Three hundred conversions can be done per day to equip a brigade combat team per week, with all M4A1 conversions to be completed by 2019. | M4 carbine | Wikipedia | 338 | 321957 | https://en.wikipedia.org/wiki/M4%20carbine | Technology | Specific firearms | null |
In addition to upgrade kits, in April 2012, the U.S. Army announced it would begin purchasing over 120,000 M4A1 carbines to start reequipping front line units from the original M4 to the new M4A1 version. The first 24,000 were to be made by Remington Arms Company. Remington was to produce the M4A1s from mid-2013 to mid-2014. After completion of that contract, it was to be between Colt and Remington to produce over 100,000 more M4A1s for the U.S. Army. Because of efforts from Colt to sue the Army to force them not to use Remington to produce M4s, the Army reworked the original solicitation for new M4A1s to avoid legal issues from Colt. On 16 November 2012, Colt's protest of Remington receiving the M4A1 production contract was dismissed. Instead of the contract being re-awarded to Remington, the Army awarded the contract for 120,000 M4A1 carbines worth $77 million to FN Herstal on 22 February 2013. The order was expected to be completed by 2018.
Replacement efforts
Replacements for the M4 have mostly focused on two factors: improving its reliability, and its penetration. The first attempt to find a replacement for the M4 came in 1986, with the Advanced Combat Rifle program, in which the caseless Heckler & Koch G11 and various flechette rifles were tested, but this was quickly dropped as these designs were mostly prototypes, which demonstrated a lack of reliability. In the 1990s, the Objective Individual Combat Weapon competition was put forth to find a replacement for the M4. Two designs were produced, both by Heckler & Koch: the XM29 OICW, which incorporated a smart grenade launcher, but was canceled in 2004 as it was too heavy, and the XM8, which was canceled in 2005 as it did not offer significant enough improvements over the M4. | M4 carbine | Wikipedia | 399 | 321957 | https://en.wikipedia.org/wiki/M4%20carbine | Technology | Specific firearms | null |
The Heckler & Koch HK416 was introduced in 2005, incorporating the same lower receiver as the M4A1, but replacing its direct impingement system with a gas-operated rotating bolt, more comparable to that of the G36. The HK416 was adopted by the Navy SEALs, Delta Force, and other special forces. In 2010, it was adopted by the Marines as the M27 Infantry Automatic Rifle. The same year, the Rangers and Navy SEALs adopted the FN SCAR, but later withdrew their purchase, as it was not a significant enough improvement over the M4A1.
Individual Carbine
The U.S. Army briefly had a tender in 2011 called the Individual Carbine, which solicited proposals for a potential M4 carbine replacement, but this was canceled in 2013 after determining that none of the entrants offered an adequate improvement over the M4.
For the Individual Carbine competition, Colt submitted their Enhanced M4 design, also known as the Colt Advanced Piston Carbine (APC). The weapon has a suppression-ready fluted barrel, which is lighter and cools better than previous M4 barrels. It is claimed to have "markedly better" accuracy. To improve reliability, Colt used an articulating link piston (ALP), which "reduces the inherent stress in the piston stroke by allowing for deflection and thermal expansion". In traditional short-stroke gas piston operating systems designed for the AR platform, the force of the piston striking the bolt carrier can push the bolt carrier downwards and into the wall of the buffer tube, leading to accelerated wear and even chipped metal. This is known as carrier tilt. The ALP allows the operating rod to wiggle to correct for the downward pressure on the bolt and transfers the force straight backwards in line with the bore and buffer assembly, eliminating the carrier tilt. This relieves stress on parts and helps to increase accuracy. The Individual Carbine competition was canceled before a winning weapon was chosen.
Next Generation Squad Weapon | M4 carbine | Wikipedia | 406 | 321957 | https://en.wikipedia.org/wiki/M4%20carbine | Technology | Specific firearms | null |
After the failure of the Individual Carbine program, the Next Generation Squad Weapon (NGSW) was started in 2017. The program aimed to replace the M4 Carbine and the M249 SAW with weapons that would compensate for their perceived deficiencies when fighting at longer ranges, as well as addressing concerns about the effectiveness of traditional 5.56x45mm ammunition against troops wearing body armor in a future peer or near-peer conflict. In order to achieve these goals, all weapon submissions were to be chambered in a new 6.8x51 mm caliber. SIG Sauer, Textron Systems, FN Herstal, True Velocity (previously Lonestar Future Weapons and General Dynamics), and PCP Tactical took part in the program. Textron submitted a cased-telescoped (CT) ammunition-firing rifle for the program; FN Herstal submitted their HAMR IAR re-chambered in 6.8mm caliber; PCP Tactical submitted a modified Desert Tech MDRx; SIG Sauer submitted a redesigned MCX variant known as the MCX-SPEAR. In early 2022, the program concluded, with SIG Sauer being declared the winner. Their rifle entry was designated the XM5 (later changed to XM7 to avoid confusion with the Colt M5), and the XM250 Squad Automatic Weapon. Operational testing and fielding were scheduled for 2024.
Design | M4 carbine | Wikipedia | 287 | 321957 | https://en.wikipedia.org/wiki/M4%20carbine | Technology | Specific firearms | null |
The M4, and its variants, is a lightweight 5.56×45mm NATO (and .223 Remington) caliber, gas-operated, magazine-fed, air-cooled selective fire AR-15-pattern firearm. Its gas operation consists of an internal piston (often incorrectly referred to as direct impingement), a rotating bolt, and bolt carrier that reciprocates into a receiver extension that is inline with the barrel. The gas system, bolt carrier, and bolt-locking design is ammunition specific, since it does not have an adjustable gas port or valve to adjust the weapon to various propellant and projectile or barrel length specific pressure behavior. The receiver is made of forged 7075-T6 aluminum, while the barrel, bolt, bolt carrier, and fire control group are made of steel; these components can be easily serviced and replaced by unit armories, enabling the addition of enhanced components and thus making the platform readily upgradable. The flattop upper receiver's Picatinny rail enables the replacement of the removable carrying handle with various optics. The furniture, including the buttstock, grip, and handguard are made of reinforced plastic, although the modular nature of the weapon means that these can be swapped by the end user. The receiver extension can accommodate either a multi-position telescoping stock or a fixed A2 or LE tactical stock. The M4 is a shorter and lighter variant of the M16A2 rifle, sharing much of the same operation mechanisms and has 80% parts commonality; the chief differences are a shorter barrel of 14.5 inches rather than 20 inches as well as a shortened receiver extension and buffer.
Two fire control groups exist for the M4 family, the three-round burst for the baseline model and the fully automatic for the M4A1. Some M4A1 may also have a heavier profile barrel initially developed for SOCOM for prolonged automatic fire; models with this heavier "SOCOM profile" barrel use the same M4A1 designation, and existing weapons can swap to the heavier profile barrel at the unit armory level. Despite being its namesake, SOCOM itself has reverted to the original lighter "government profile" barrel while adopting a longer "mid length" gas system with its newer Upper Receiver Group-Improved (URG-I) modifications. As the modifications only affect the upper receiver assembly, rifles with the URG-I still retain the M4A1 designation. | M4 carbine | Wikipedia | 492 | 321957 | https://en.wikipedia.org/wiki/M4%20carbine | Technology | Specific firearms | null |
The M4's maneuverability makes it beneficial for non-infantry troops (vehicle crews, clerks and staff officers), as well as for close quarters battle. The M4, along with the M16A4, has mostly replaced the M16A2 in the Army and Marines. The U.S. Air Force, for example, has transitioned completely to the M4 for Security Forces squadrons, while other armed personnel retain the M16A2. The U.S. Navy uses M4A1s for Special Operations and vehicle crews. However, the M4's shorter barrel reduces its range, with its rear iron sights integrated in the (removable) carry handle only adjustable from up to , compared to the M16A2 rear iron sights integrated in the fixed carry handle, which can reach up to .
Accessories
Like all the variants of the M16, the M4 and the M4A1 can be fitted with many accessories, such as slings, night-vision devices, flash suppressors, suppressors, laser sights, telescopic sights, bipods, M9 bayonet, either M203 or M320 grenade launcher, M26-MASS shotgun, forward hand grips, a detachable rail-mounted carrying handle, or anything else compatible with a MIL-STD-1913 picatinny rail.
Other common accessories include the AN/PEQ-2, AN/PEQ-15 multi-mode laser, AN/PEQ-16 Mini Integrated Pointing Illumination Module (MIPIM), Trijicon TA01 and TA31 Advanced Combat Optical Gunsights (ACOG), EOTech 550 series holographic sights, and Aimpoint M68 Close Combat Optic. Visible and infrared lights of various manufacturers are commonly attached using various mounting methods. As with all versions of the M16, the M4 accepts a blank-firing attachment (BFA) for training purposes. | M4 carbine | Wikipedia | 393 | 321957 | https://en.wikipedia.org/wiki/M4%20carbine | Technology | Specific firearms | null |
The M4 and the M4A1 feed from 30-round STANAG magazines. Other types of STANAG compatible magazines with different capacities may also be used. In January 2017, a USMC unit deployed with suppressors mounted to every infantry M4 service weapon. Exercises showed that having all weapons suppressed improved squad communication and surprise during engagements; disadvantages included additional heat and weight, increased maintenance, and the greater cost of equipping so many troops with the attachment. In July 2020, the Marine Corps announced it would be ordering suppressors for use by all M4 carbines used by close combat units. The Marines began to roll out suppressors for all M4/M4A1 carbines in infantry, reconnaissance and special operations units in December 2020.
Special Operations Peculiar Modification
In 1992, U.S. Special Operations Command (USSOCOM) developed the Special Operations Peculiar Modification (SOPMOD) Block I kit for the carbines used by US Special Operations Forces units operating under its command. The kit features an M4A1, a Rail Interface System (RIS) handguard developed by Knight's Armament Company (KAC), a shortened quick-detachable M203 grenade launcher and leaf sight, a KAC sound suppressor, a KAC back-up rear sight, an Insight Technologies AN/PEQ-2A visible laser/infrared designator, along with Trijicon's ACOG TA-01NSN model and Reflex sights, and a night vision sight, among many other accessories. This kit was designed to be configurable (modular) for various missions, and the kit is currently in service with special operations units. | M4 carbine | Wikipedia | 341 | 321957 | https://en.wikipedia.org/wiki/M4%20carbine | Technology | Specific firearms | null |
In 2002, the Block II modification kit was adopted featuring two new upper receivers: the Special Purpose Receiver (SPR) with a barrel and Close Quarter Battle Receiver (CQBR) with a barrel. M4A1s fitted with the SPR were designated by the Navy as the Mk 12 Special Purpose Rifle, a type of designated marksman rifle. M4A1s with the CQBR were designated the Mk 18 Mod 0. The Block II program then focused on component improvements to the M4A1, with the adoption of the heavier "SOCOM profile" barrel in 2004 and free-float Rail Interface System II (RIS-II) handguard from Daniel Defense in 2008. Owing to the modularity of the AR-15/M4 platform, some operators have replaced issued optics, handguards, and buttstocks with aftermarket ones.
In 2018, the Upper Receiver Group-Improved (URG-I) modification kit (unofficially the Block III) was approved for the conversion of Block I and Block II carbine's upper receiver "to an improved barrel and rail assembly.." which includes a lighter free-float handguard from Geissele Automatics that incorporates the Magpul Industries M-LOK rail interface system. The URG-I also replaces the Block II's heavier barrel with a standard "government profile" cold hammer forged barrel with a longer gas system.
Variants
The initial order of M4 carbines had a fixed carrying handle and rear sight similar to the M16A2. The flattop upper receiver with the Picatinny rail was introduced with the M4A1 variant in 1994, and all subsequent orders for all M4 variants would have a flattop upper receiver. Variants of the carbine built by different manufacturers are also in service with many other foreign special forces units, such as the Australian Special Air Service Regiment (SASR). While the SASR uses weapons of essentially the same pattern built by Colt for export (Colt uses different models to separate weapons for the U.S. military and those for commercial/export purposes), the British Special Air Service uses a variant on the basic theme, the Colt Canada C8SFW.
M4 MWS (Modular Weapon System) | M4 carbine | Wikipedia | 454 | 321957 | https://en.wikipedia.org/wiki/M4%20carbine | Technology | Specific firearms | null |
Colt Model 925 carbines were tested and fitted with the KAC M4 RAS under the designation M4E2, but this designation appears to have been scrapped in favor of mounting this system to existing carbines without changing the designation. The U.S. Army Field Manual specifies for the Army that adding the Rail Adapter System (RAS) turns the weapon into the M4 MWS or modular weapon system.
M4A1
The M4A1 carbine is a fully automatic variant of the basic M4 carbine. The M4A1 was developed in May 1991 and entered service in 1994; starting in 2014 the U.S. Army began upgrading all of its existing M4s to the M4A1 standard. The M4A1 was the first M4 model with the removable carry handle. The M4A1 has a "S-1-F" (safe/semi-automatic/fully automatic) trigger group, while the M4 has a "S-1-3" (safe/semi-automatic/3-round burst) trigger group. The M4A1 is used by almost all U.S. special operation units; and is the standard service rifle across the U.S. Army (including conventional forces). It has a maximum effective range of . The fully automatic trigger gives a more consistent trigger pull, which leads to better accuracy. According to Mark Westrom, owner of ArmaLite, Inc., automatic fire is better for clearing rooms than burst fire.
A subvariant of the M4A1 uses a heavier barrel than the standard M4, as the regular M4 barrel, which can fire 6,000 rounds before requiring inspection for possible replacement, was not sufficient for the higher consumption of ammunition by SOCOM operators. The redesigned barrel, colloquially referred to as the "SOCOM barrel", has an increased diameter in the area between the receiver and front sight. Despite the different barrel profile, this subvariant did not receive a new designation, and was still referred to as the M4A1. Ironically, SOCOM itself would dispense with its namesake heavier barrel and return to the original "government profile" with its Upper Receiver Group-Improved (URG-I) program's mid-length gassed, cold hammer forged barrels.
Mk 18 CQBR | M4 carbine | Wikipedia | 474 | 321957 | https://en.wikipedia.org/wiki/M4%20carbine | Technology | Specific firearms | null |
The Close Quarters Battle Receiver (CQBR) was originally a Special Operations Peculiar Modification (SOPMOD) program item that would increase the close quarters maneuverability of the M4A1 by mating the lower receiver with a barreled upper receiver; with the CQBR installed, the weapon would then be classified as the Mk. 18 CQBR. The Mk. 18 CQBR may be issued as a standalone complete weapon system to SOCOM personnel, or as a separate upper receiver for their M4A1 to enable greater mission flexibility.
Mk 12 SPR
The SOPMOD program also introduced the Special Purpose Receiver (SPR), a barreled upper receiver that would be mated to an M4A1 lower receiver to allow the weapon to serve as a designated marksman rifle (DMR). Although originally intended as an upper receiver kit for the M4A1 like the CQBR, the SPR would eventually be issued as a standalone complete rifle designated the Mk. 12 Special Purpose Rifle, with some assembled from M4A1 lower receivers.
SOPMOD Block II
The SOPMOD Block II is a more radical modification kit for the baseline M4A1 that can be fitted at first-echelon unit maintenance level. Components of the Block II were phased in gradually, but the most distinctive feature is the free-floated Daniel Defense Rail Interface System II (RIS II), first issued in 2008. The RIS II is available in 9.5 inches for the Mk 18 Mod 1 or 12.5 inches for the M4A1. Other components of the Block II include the L3 Advanced Target Pointer Illuminator Aiming Laser (ATPIAL), or the AN/PEQ-15 as well as the LA5 high-power variants, and the ELCAN SpecterDR 1-4 optic.
Upper Receiver Group-Improved (URG-I)
The Upper Receiver Group-Improved (URG-I) is a U.S. Army Special Operations Command (USASOC) program to further improve the durability and reliability of the SOPMOD Block II by introducing additional component improvements. First fielded in 2018, the main improvements are the lighter Geissele Mark 16 free-float rail that incorporates M-LOK as the mounting method and a Daniel Defense cold hammer-forged barrel that returns to the lighter "government" profile contour as well as a mid-length gas system. Although initially an Army program, the URG-I has seen use by other components of SOCOM as well. | M4 carbine | Wikipedia | 512 | 321957 | https://en.wikipedia.org/wiki/M4%20carbine | Technology | Specific firearms | null |
GAU-5/A
The GAU-5/A Aircrew Self Defense Weapon (ASDW) is an Air Force modified M4 with a detachable barrel and handguard assembly, folding pistol grip, and fold-down iron sights to enable compact packaging. This weapon is stowed in ejection seats of tactical aircraft and is intended to allow aircrew who egress in hostile environments to better defend themselves until rescue than existing handguns. The weapons entered service in 2018. Confusingly, this weapon shares the same designation as the Air Force CAR-15 variant in service since 1966.
Performance
The M4 carbine has been used for close quarters operations where the M16 would be too long and bulky to use effectively. It has been a compact, light, customizable, and accurate weapon. Like other firearms, failure to properly maintain the M4 can result in malfunctions. This became apparent as it saw continued use in the sandy environments of Iraq and Afghanistan. Despite this, in post-combat surveys, 94% of soldiers rated the M4 as an effective weapons system. | M4 carbine | Wikipedia | 227 | 321957 | https://en.wikipedia.org/wiki/M4%20carbine | Technology | Specific firearms | null |
2006 CNA report
In December 2006, the Center for Naval Analyses (CNA) released a report on U.S. small arms in combat. The CNA conducted surveys on 2,608 troops returning from combat in Iraq and Afghanistan over the previous 12 months. Only troops who fired their weapons at enemy targets were allowed to participate. 917 troops were armed with M4 Carbines, making up 35% of the survey. 89% of M4 users reported they were satisfied with the weapon. 90% were satisfied with handling qualities such as handguards, size, and weight. M4 users had the highest levels of satisfaction with weapon performance, including 94% with accuracy, 92% with range, and 93% with rate of fire. Only 19% of M4 users reported a stoppage, and 82% of those that experienced a stoppage said it had little impact on their ability to clear the stoppage and re-engage their target. The lowest rated weapon was the M9, and the M249 had the highest rate of stoppages. 53% of the M4 users never experienced failures of their magazines to feed. 81% did not need their rifles repaired while in theater. 80% were confident in the M4's reliability, defined as confidence their weapon will fire without malfunction, and 83% were confident in its durability, defined as confidence their weapon will not break or need repair. Both factors were attributed to high levels of soldiers performing their own maintenance. 54% of M4 users offered recommendations for improvements. 20% of requests were for greater bullet lethality, and 10% were for better quality magazines, as well as other minor recommendations. Only 75% of M16 users were satisfied with it, and some expressed their desire to be issued the M4. Some issues from this report have been addressed with the issuing of the improved STANAG magazine in March 2009, and the M855A1 Enhanced Performance Round in June 2010. | M4 carbine | Wikipedia | 401 | 321957 | https://en.wikipedia.org/wiki/M4%20carbine | Technology | Specific firearms | null |
2007 dust test
In summer and fall 2007, the Army tested the M4 against three other carbines in "sandstorm conditions" at Aberdeen Proving Ground, Maryland: the Heckler & Koch XM8, Fabrique Nationale de Herstal SOF Combat Assault Rifle (SCAR) and the Heckler & Koch HK416. Ten of each type of rifle were used to fire 6,000 rounds each, for a total of 60,000 rounds per rifle type. The M4 suffered far more stoppages than its competitors: 882 stoppages, 19 requiring an armorer to fix. The XM8 had the fewest stoppages, 116 minor stoppages and 11 major ones, followed by the FN SCAR with 226 stoppages and the HK416 with 233.
Despite 863 minor stoppages—termed "class one" stoppages, which require 10 seconds or less to clear, or "class two" stoppages, which require more than ten seconds to clear—the M4 functioned well, with over 98% of the 60,000 total rounds firing without a problem. The Army said it planned to improve the M4 with a new cold-hammer-forged barrel to give longer life and more reliable magazines to reduce the stoppages. Magazine failures caused 239 of the M4's failures. Army officials said the new magazines could be combat-ready by spring if testing went well. The Army began issuing an improved STANAG magazine in March 2009.
According to the Army, the M4 only suffered 296 stoppages and said that the high number reported could be attributed to discrepancies in the scoring process. The Army testing command stated that, if the number of stoppages caused by a broken part met some threshold, they would be eliminated from the final report pending redesign of the part. The methodology of the test has been debated, as many of the M4s in the test had already seen use, whereas the other rifles were brand new, and that the wide variance in results between summer and fall showed that the test was not accurate, as it was not repeatable with consistent results. Furthermore, the trial M4s had burst-mode fire groups, which are more complicated and prone to failure than the fully automatic fire groups the other manufacturers presented for testing. | M4 carbine | Wikipedia | 474 | 321957 | https://en.wikipedia.org/wiki/M4%20carbine | Technology | Specific firearms | null |
There were three extreme dust tests performed in 2007. The second test results showed a large difference from the last test with the M4 having 148 class 1 stoppages caused by rifle malfunctions and 148 class 1 stoppages caused by magazine stoppages. The full-size M16 rifle had 61 stoppages during the same extreme dust test.
Reliability
In early 2010, two journalists from the New York Times spent three months with soldiers and Marines in Afghanistan. While there, they questioned around 100 infantrymen about the reliability of their M4 carbines, as well as the M16 rifle. Troops did not report reliability problems with their rifles. While only 100 troops were asked, they fought at least a dozen intense engagements in Helmand Province, where the ground is covered in fine powdered sand (called "moon dust" by troops) that can stick to firearms. Weapons were often dusty, wet, and covered in mud. Intense firefights lasted hours with several magazines being expended. Only one soldier reported a jam when his M16 was covered in mud after climbing out of a canal. The weapon was cleared and resumed firing with the next chambered round. Furthermore, a Marine chief warrant officer reported that there were no issues with his battalion's 700 M4s and 350 M16s.
The reliability of the M4 has increased as the design was upgraded. In 1990, the M4 was required to fire 600 mean rounds between stoppages using M855 ammunition. In 2013, the current M4A1 version can fire 1,691 mean rounds between stoppages using M855A1 ammunition. During the 2009 Marine Corps Infantry Automatic Rifle testing, the Colt IAR displayed a MRBS of CLASS I/II Stoppages of 952 rounds, with a MRBEFF (Mean Rounds Between Essential Function Failure) of Class III Stoppages of 60,000 rounds. | M4 carbine | Wikipedia | 388 | 321957 | https://en.wikipedia.org/wiki/M4%20carbine | Technology | Specific firearms | null |
Gas piston
An array of firearms accessory makers have offered gas piston conversion kits for the M4. The claimed benefits include less needed lubrication for the bolt carrier group to run reliably and reduced fouling. The argument against it is increased weight and reduced accuracy. The Enhanced M4 uses an articulating link piston operating system. Complicating the Army search for higher reliability in the M4 is a number of observations of M4 gas piston alternatives that suffer unintended design problems. The first is that many of the gas piston modifications for the M4 isolate the piston so that piston jams or related malfunction require the entire weapon be disassembled, such disassembly cannot be performed by the end-user and requires a qualified armorer to perform out of field, whereas almost any malfunction with the direct-impingement system can be fixed by the end-user in field. The second is that gas piston alternatives use an off-axis operation of the piston that can introduce carrier tilt, whereby the bolt carrier fails to enter the buffer tube at a straight angle, resulting in part wearing. This can also tilt the bolt during extraction, leading to increased bolt lug failures. The third is that the use of a sound suppressor results in hot gases entering the chamber, regardless of a direct-gas impingement or gas piston design choice. The gas piston system may also cause the firearm to become proprietary to the manufacturer, making modifications and changes with parts from other manufacturers difficult.
Accuracy
In a study conducted by the Army Marksmanship Unit, they found that at a distance of , the M16 achieved a grouping, and the M4 achieved a grouping, which dropped to and respectively when using match grade ammunition. As the average male torso is wide, author Chris McNab concluded that this meant the M4 can be consistently accurate up to 300 yards, and noted that the frequent usage of optical attachments meant it could be accurate to higher ranges. | M4 carbine | Wikipedia | 403 | 321957 | https://en.wikipedia.org/wiki/M4%20carbine | Technology | Specific firearms | null |
ArmWest, LLC modified M4
In 2014, American firearms designer Jim Sullivan provided a video interview regarding his contributions to the M16 and M4 family of rifles while working for Armalite. A noted critic of the M4, he illustrates the deficiencies found in the rifle in its current configuration. In the video, he demonstrates his "ArmWest, LLC modified M4", with enhancements he believes necessary to rectify the issues with the weapon. Proprietary issues aside, the weapon is said to borrow features in his prior development, the Ultimax. Sullivan has stated (without exact details as to how) the weapon can fire from the closed bolt in semi-automatic and switch to open bolt when firing in fully automatic, improving accuracy. The weight of the cyclic components of the gun has been doubled (while retaining the weapon's weight at less than 8 pounds). Compared to the standard M4, which in automatic fires 700–950 rounds a minute, the rate of fire of the ArmWest, LLC M4 is heavily reduced both to save ammunition and reduce barrel wear. The reduced rate also renders the weapon more controllable and accurate in automatic firing.
Manufacturers
Colt's Manufacturing Company, US
Remington Arms Company, US
FN Herstal, Belgium
SME Ordnance, Malaysia
Sarsılmaz, Turkey
United Defense Manufacturing Corporation, Philippines
Trademark issues
The M4 was developed and produced for the United States government by Colt Firearms, which had an exclusive contract to produce the M4 family of weapons through 2011. However, a number of other manufacturers offer M4-like firearms. Colt previously held a U.S. trademark on the term "M4". Many manufacturers offer production firearms that are essentially identical to a military M4, but with a barrel. The Bushmaster M4 Type Carbine is a popular example. Civilian models are sometimes colloquially referred to as "M4gery" ( , a portmanteau of "M4" and "forgery.") Colt had maintained that it retained sole rights to the M4 name and design, while other manufacturers had long maintained that Colt had been overstating its rights, and that "M4" had now become a generic term for a shortened AR-15. | M4 carbine | Wikipedia | 457 | 321957 | https://en.wikipedia.org/wiki/M4%20carbine | Technology | Specific firearms | null |
In April 2004, Colt filed a lawsuit against Heckler & Koch and Bushmaster Firearms, claiming acts of trademark infringement, trade dress infringement, trademark dilution, false designation of origin, false advertising, patent infringement, unfair competition, and deceptive trade practices. Heckler & Koch later settled out of court, changing one product's name from "HK M4" to "HK416". However, on December 8, 2005, a district court judge in Maine granted a summary judgment in favor of Bushmaster Firearms, dismissing all of Colt's claims except for false advertising. On the latter claim, Colt could not recover monetary damages. The court also ruled that "M4" was now a generic name and that Colt's trademark should be revoked.
Users | M4 carbine | Wikipedia | 155 | 321957 | https://en.wikipedia.org/wiki/M4%20carbine | Technology | Specific firearms | null |
Afghanistan: Former Afghan National Army commando stocks in use by the Taliban.
: Used by Albanian Land Force 2015.
: M4/M4A1s announced to be sold via FMS program in 2017.
: Used by Argentine Army, Argentine Navy and Argentine National Gendarmerie
: M4A1 (designated M4A5), used by Special Operations Command, Clearance Divers, and Police Tactical Groups.
: M4 Carbine used by the special military units and State Border Service (DSX).
: M4A1s sold as a 2008 Foreign Military Sales package. More M4/M4A1s announced to be sold via FMS program in 2017.
: M4s/M4A1s sold as part of a 2006 Foreign Military Sales package. More M4/M4A1s announced to be sold via FMS program in 2017.
: M4A1s used by the military and air guard units.
: M4s used by UMOPAR and GTIDE units of the Policia Nacional. M4A1 in use with rangers.
: Used by Civil Police, Military Police of Espirito Santo State, Military Police of Rio de Janeiro State, the Brazilian Federal Police and Special Forces of the Brazilian Army, Brazilian Navy.
: User since 2003, several hundred purchased for Croatian ISF contingent as well as Special Forces.
: Bushmaster M4A3 B.M.A.S., Daniel Defense M4A1 and MK18 is used by (601st Special forces group, Military police, 43rd Airborne mechanized battalion) of Czech Army.
: A variant is made by Norinco as the Norinco CQ. CQ-A carbine variant used by the Sichuan Police Department, Chongqing SWAT teams, and the Snow Leopard Commando Unit.
: M4A1s as part of a 2008 Foreign Military Sales. More M4/M4A1s announced to be sold via FMS program in 2017.
: M4s sold as a 2008 Foreign Military Sales package.
: M4s sold as part of a 2007 Foreign Military Sales package. Additional M4s sold as a 2008 Foreign Military Sales package.
: Used by the 1er RPIMa
: Bushmaster M4s being replaced by Colt M4s for the military. More M4/M4A1s announced to be sold via FMS program in 2017. Joint Georgian-Israeli production M4 based "GI-4" launched in 2021 | M4 carbine | Wikipedia | 496 | 321957 | https://en.wikipedia.org/wiki/M4%20carbine | Technology | Specific firearms | null |
: M16A2s and M4s are used by the "Special Forces" branch as well as by the airborne battalions of the Hellenic Army.
: M4A1 SOPMOD by Hungarian MH 34th Bercsényi László special operation battalion More M4/M4A1s announced to be sold via FMS program in 2017.
: M4A1s as part of a 2008 Foreign Military Sales. M4A1 is used by the Mizoram Armed Police, PARA SF and Force One of the Mumbai Police.
: Used by Detachment 88 Counter-terrorism Police Squad operators. Also used by Komando Pasukan Katak (Kopaska) tactical diver group and Komando Pasukan Khusus (Kopassus) special forces group.
: Used by the Iraqi Army. Main weapon of the Iraqi National Counter-Terrorism Force. More M4/M4A1s announced to be sold via FMS program in 2017.
: Used by Peshmerga.
: Sold as part of a January 2001 Foreign Military Sales package to Israel. Standard issue in the Israel Defense Forces, but it has been gradually replaced with the IWI Tavor since 2001.
: Special Forces
: M4s sold as part of a 2007 Foreign Military Sales package.
: M4A1s as part of a 2008 Foreign Military Sales package. M4A1 SOPMOD rifles are in use by the Japanese Special Forces Group, but is supposedly denied by the JGSDF after Ishiba was arrested for violating American export laws.
: M4s sold as part of a 2007 Foreign Military Sales package. Additional M4s sold as a 2008 Foreign Military Sales package. More M4/M4A1s announced to be sold via FMS program in 2017.
: Used by Kenyan troops Kenya Defence Forces in AMISOM ops.
: M4 components being sold to Lebanese special forces. M4/M4A1s sold as a 2008 Foreign Military Sales package. More M4/M4A1s announced to be sold via FMS program in 2017.
: Made under license by SME Ordnance Sdn Bhd. Used by military and police special forces.
: 1,070 M4s, sold as part of a 2005 Foreign Military Sales package.
: Used by NZSAS operators and standard issue to New Zealand Police including Special Tactics Group and Armed Offenders Squad units.
: Used by the Army of North Macedonia
: M4/M4A1s announced to be sold via FMS program in 2017. | M4 carbine | Wikipedia | 508 | 321957 | https://en.wikipedia.org/wiki/M4%20carbine | Technology | Specific firearms | null |
: M4A1 variant used by the Special Forces of the Pakistani military besides the POF G3P4 standard rifle for the Pakistani military— also used by the Special Security Unit (SSU) of the Sindh Police. More M4/M4A1s announced to be sold via FMS program in 2017.
: Used by Palestinian security forces.
: M4A1s sold as a 2008 Foreign Military Sales package. More M4/M4A1s announced to be sold via FMS program in 2017.
: Airforce Special Group and anti-narcotics units
: Colt M4/M4A1s sold as a 2008 Foreign Military Sales package. 63,000 R4A3 rifles from Remington Arms for the Philippine Army and the Philippine Marine Corps. Several units also used by the Defense Intelligence and Security Group.
: Used by Wojska Specjalne military unit JW Grom.
: M4/M4A1s announced to be sold via FMS program in 2017.
: Used in limited quantities by FSB Alpha and spotted in hands of RuAF in a training exercise.
: M4/M4A1s announced to be sold via FMS program in 2017. 2,200 M4s sold through FMS program in 2019.
: Used by Gendarmery and Special Anti-Terrorist Unit.
: Used by the Commandos and the Police Coast Guard (only the Port Squadron and the Coastal Patrol Squadron) of the Singapore Police Force.
: M4/M4A1s announced to be procured via FMS program in 2017.
: 15000 M4A1s purchased directly from US Army stocks in 2024 to act as interim service weapons while awaiting full delivery of the new Automatkarbin 24
: Used by Republic of China Army and National Police Agency
: M4A1s sold as part of a 2006 Foreign Military Sales package.
: M4/M4A1s sold as a 2008 Foreign Military Sales package.
: Used by the Tunisian Army's Special Forces Group (GFS), 51st Infantry Navy Commandos Regiment, Presidential Guard and various National Guard and Police special forces units. Used by the Unité Spéciale – Garde Nationale.
: Produced under license by Sarsılmaz Firearms.
: Used by Ugandan troops in AMISOM ops.
: Purchased 2,500 M4 carbines in 1993.
: Colt M4 and Bushmaster M4 carbines for Special Operation Group (Metropolitan Police)
: M4s sold as part of a 2006 Foreign Military Sales package. | M4 carbine | Wikipedia | 508 | 321957 | https://en.wikipedia.org/wiki/M4%20carbine | Technology | Specific firearms | null |
Former users
: Used by Afghan National Army commandos during the Taliban insurgency. M4s sold as part of a 2006 Foreign Military Sales package. Additional M4s sold as a 2008 Foreign Military Sales package. Captured stocks currently in use with the Islamic Emirate of Afghanistan.
Conflicts
1990s
Colombian conflict (1964–present)
Civil conflict in the Philippines (1969–present)
Insurgency in Jammu and Kashmir (1989–present)
Kosovo War (1998–1999), first US military usage of the M4 carbine
2000s
War in Afghanistan (2001–2021)
Internal conflict in Peru
Iraq War (2003–2011)
South Thailand insurgency (2004–present)
2006 Lebanon War (2006)
Mexican drug war (2006–present)
Russo-Georgian War (2008)
Gaza War (2008–2009)
Insurgency in Paraguay
2010s
Syrian civil war (2011–present)
Lahad Datu standoff (2013)
War in Iraq (2013–2017)
Battle of Arsal (2014)
Yemeni civil war (2014–present)
Battle of Marawi (2017)
2020s
2021 Beirut clashes (2021)
Russian invasion of Ukraine (2022–present)
Israel–Hamas war (2023–present)
2024 Enga Clashes (2024) | M4 carbine | Wikipedia | 246 | 321957 | https://en.wikipedia.org/wiki/M4%20carbine | Technology | Specific firearms | null |
Beekeeping (or apiculture) is the maintenance of bee colonies, commonly in artificial beehives. Honey bees in the genus Apis are the most commonly kept species but other honey producing bees such as Melipona stingless bees are also kept. Beekeepers (or apiarists) keep bees to collect honey and other products of the hive: beeswax, propolis, bee pollen, and royal jelly. Other sources of beekeeping income include pollination of crops, raising queens, and production of package bees for sale. Bee hives are kept in an apiary or "bee yard".
The earliest evidence of humans collecting honey are from Spanish caves paintings dated 6,000 BCE, however it is not until 3,100 BCE that there is evidence from Egypt of beekeeping being practiced.
In the modern era, beekeeping is often used for crop pollination and the collection of its by products, such as wax and propolis. The largest beekeeping operations are agricultural businesses but many small beekeeping operations are run as a hobby. As beekeeping technology has advanced, beekeeping has become more accessible, and urban beekeeping was described as a growing trend as of 2016. Some studies have found city-kept bees are healthier than those in rural settings because there are fewer pesticides and greater biodiversity in cities.
History
Early history
At least 10,000 years ago, humans began to attempt to maintain colonies of wild bees in artificial hives made from hollow logs, wooden boxes, pottery vessels, and woven straw baskets known as skeps. Depictions of humans collecting honey from wild bees date to 10,000 years ago. Beekeeping in pottery vessels began about 9,000 years ago in North Africa. Traces of beeswax have been found in potsherds throughout the Middle East beginning about 7,000 BCE. Domestication of bees is shown in Egyptian art from around 4,500 years ago. Simple hives and smoke were used, and honey was stored in jars, some of which were found in the tombs of pharaohs such as Tutankhamun. In the 18th century, European understanding of the colonies and biology of bees allowed the construction of the movable comb hive so honey could be harvested without destroying the entire colony. | Beekeeping | Wikipedia | 452 | 322091 | https://en.wikipedia.org/wiki/Beekeeping | Technology | Forms | null |
Honeybees were kept in Egypt from antiquity. On the walls of the sun temple of Nyuserre Ini from the Fifth Dynasty before 2,422 BCE, workers are depicted blowing smoke into hives as they remove honeycombs. Inscriptions detailing the production of honey are found on the tomb of Pabasa from the Twenty-sixth Dynasty , in which cylindrical hives are depicted along with people pouring honey into jars.
An inscription records the introduction of honey bees into the land of Suhum in Mesopotamia, where they were previously unknown:
The oldest archaeological finds directly relating to beekeeping have been discovered at Rehov, a Bronze and Iron Age archaeological site in the Jordan Valley, Israel. Thirty intact hives made of straw and unbaked clay were discovered in the ruins of the city, dating from about 900 BCE, by archaeologist Amihai Mazar. The hives were found in orderly rows, three high, in a manner that according to Mazar could have accommodated around 100 hives, held more than one million bees and had a potential annual yield of of honey and of beeswax, and are evidence an advanced honey industry in Tel Rehov, Israel 3,000 years ago.
In ancient Greece, in Crete and Mycenae, there existed a system of high-status apiculture that is evidenced by the finds of hives, smoking pots, honey extractors and other beekeeping paraphernalia in Knossos. Beekeeping was considered a highly valued industry controlled by beekeeping overseers—owners of gold rings depicting apiculture scenes rather than religious ones as they have been reinterpreted recently, contra Sir Arthur Evans.
Aspects of the lives of bees and beekeeping are discussed at length by Aristotle. Beekeeping was also documented by the Roman writers Virgil, Gaius Julius Hyginus, Varro, and Columella.
Beekeeping has been practiced in ancient China since antiquity. In a book written by Fan Li (or Tao Zhu Gong) during the Spring and Autumn period are sections describing beekeeping, stressing the importance of the quality of the wooden box used and its effects on the quality of the honey. The Chinese word for honey mi (), reconstructed Old Chinese pronunciation ) was borrowed from proto-Tocharian *ḿət(ə) (where *ḿ is palatalized; cf. Tocharian B mit), cognate with English . | Beekeeping | Wikipedia | 487 | 322091 | https://en.wikipedia.org/wiki/Beekeeping | Technology | Forms | null |
The ancient Maya domesticated a species of stingless bee, which they used for several purposes, including making balché, a mead-like alcoholic drink. By 300 BCE they had achieved the highest levels of stingless beekeeping practices in the world. The use of stingless bees is referred to as meliponiculture, which is named after bees of the tribe Meliponini such as Melipona quadrifasciata in Brazil. This variation of beekeeping still occurs today. For instance, in Australia, the stingless bee Tetragonula carbonaria is kept for the production of honey.
Scientific study of honey bees
European natural philosophers began to scientifically study bee colonies in the 18th century. Eminent among these scientists were Swammerdam, René Antoine Ferchault de Réaumur, Charles Bonnet and François Huber. Swammerdam and Réaumur were among the first to use a microscope and dissection to understand the internal biology of honey bees. Réaumur was among the first to construct a glass-walled observation hive to better observe activities inside hives. He observed queens laying eggs in open cells but did not know how queens were fertilized; the mating of a queen and drone had not yet been observed and many theories held queens were "self-fertile" while others believed a vapor or "miasma" emanating from the drones fertilized queens without physical contact. Huber was the first to prove by observation and experiment that drones physically inseminate queens outside the confines of the hive, usually a great distance away. | Beekeeping | Wikipedia | 318 | 322091 | https://en.wikipedia.org/wiki/Beekeeping | Technology | Forms | null |
Following Réaumur's design, Huber built improved glass-walled observation hives and sectional hives that could be opened like the leaves of a book. This allowed the inspection of individual wax combs and greatly improved direct observation of hive activity. Although he went blind before he was twenty, Huber employed a secretary named François Burnens to make daily observations, conduct experiment and keep accurate notes for more than twenty years. Huber confirmed a hive consists of one queen, who is the mother of every female worker and male drone in the colony. He was also the first to confirm mating with drones takes place outside hives and that queens are inseminated in successive matings with male drones, which occur high in the air at a great distance from the hive. Together, Huber and Burnens dissected bees under the microscope, and were among the first to describe the ovaries and spermatheca (sperm store) of queens, as well as the penis of male drones. Huber is regarded as "the father of modern bee-science" and his work Nouvelles Observations sur Les Abeilles (New Observations on Bees) revealed all of the basic scientific facts of the biology and ecology of honeybees.
Hive designs
Before the invention of the movable comb hive, the harvesting of honey frequently resulted in the destruction of the whole colony. The wild hive was broken into using smoke to quieten the bees. The honeycombs were pulled out and either immediately eaten whole or crushed, along with the eggs, larvae, and honey they held. A sieve or basket was used to separate the liquid honey from the demolished brood nest. In medieval times in northern Europe, although skeps and other containers were made to house bees, the honey and wax were still extracted after the bee colony was killed. This was usually accomplished by using burning sulfur to suffocate the colony without harming the honey within. It was impossible to replace old, dark-brown brood comb in which larval bees are constricted by layers of shed pupal skins.
The movable frames of modern hives are considered to have been developed from the traditional basket top bar (movable comb) hives of Greece, which allowed the beekeeper to avoid killing the bees. The oldest evidence of their use dates to 1669, although it is probable their use is more than 3,000 years old. | Beekeeping | Wikipedia | 486 | 322091 | https://en.wikipedia.org/wiki/Beekeeping | Technology | Forms | null |
Intermediate stages in the transition from older methods of beekeeping were recorded in 1768 by Thomas Wildman, who described advances over the destructive, skep-based method so bees no longer had to be killed to harvest their honey. Wildman fixed an array of parallel wooden bars across the top of a straw hive in diameter "so that there are in all seven bars of deal to which the bees fix their combs", foreshadowing future uses of movable-comb hives. He also described using such hives in a multi-story configuration, foreshadowing the modern use of supers: he added successive straw hives below and later removed the ones above when free of brood and filled with honey so the bees could be separately preserved at the harvest the following season. Wildman also described the use of hives with "sliding frames" in which the bees would build their comb.
Wildman's book acknowledges the advances in knowledge of bees made by Swammerdam, Maraldi, and de Réaumur—he includes a lengthy translation of Réaumur's account of the natural history of bees. Wildman also describes the initiatives of others in designing hives for the preservation of bees when taking the harvest, citing reports from Brittany in the 1750s due to the Comte de la Bourdonnaye. Another hive design was invented by Rev. John Thorley in 1744; the hive was placed in a bell jar that was screwed onto a wicker basket. The bees were free to move from the basket to the jar, and honey was produced and stored in the jar. The hive was designed to keep the bees from swarming as much as they would have in other hive designs. | Beekeeping | Wikipedia | 346 | 322091 | https://en.wikipedia.org/wiki/Beekeeping | Technology | Forms | null |
In the 19th century, changes in beekeeping practice were completed through the development of the movable comb hive by the American Lorenzo Lorraine Langstroth, who was the first person to make practical use of Huber's earlier discovery of a specific spatial distance between the wax combs, later called the bee space, which bees do not block with wax but keep as a free passage. Having determined this bee space, which is commonly given as between , though up to has been found in populations in Ethiopia. Langstroth then designed a series of wooden frames within a rectangular hive box, carefully maintaining the correct space between successive frames. He found the bees would build parallel honeycombs in the box without bonding them to each other or to the hive walls. This enables the beekeeper to slide any frame out of the hive for inspection without harming the bees or the comb; and protecting the eggs, larvae and pupae in the cells. It also meant combs containing honey could be gently removed and the honey extracted without destroying the comb. The emptied honeycombs could then be returned intact to the bees for refilling. Langstroth's book The Hive and Honey-bee (1853), describes his rediscovery of the bee space and the development of his patent movable comb hive. The invention and development of the movable comb hive enabled the growth of large-scale, commercial honey production in both Europe and the U.S.
20th and 21st century hive designs | Beekeeping | Wikipedia | 302 | 322091 | https://en.wikipedia.org/wiki/Beekeeping | Technology | Forms | null |
Langstroth's design of movable comb hives was adopted by apiarists and inventors in both North America and Europe, and a wide range of moveable comb hives were developed in England, France, Germany and the United States. Classic designs evolved in each country; Dadant hives and Langstroth hives are still dominant in the U.S.; in France the De-Layens trough hive became popular, in the UK a British National hive became standard by the 1930s, although in Scotland the smaller Smith hive is still popular. In some Scandinavian countries and in Russia, the traditional trough hive persisted until late in the 20th century and is still kept in some areas. The Langstroth and Dadant designs, however, remain ubiquitous in the U.S. and in many parts of Europe, though Sweden, Denmark, Germany, France and Italy all have their own national hive designs. Regional variations of hive were developed according to climate, floral productivity and reproductive characteristics of the subspecies of native honey bees in each bio-region.
The differences in hive dimensions are insignificant in comparison to the common factors in these hives: they are all square or rectangular; they all use movable wooden frames; and they all consist of a floor, brood-box, honey super, crown-board and roof. Hives have traditionally been constructed from cedar, pine or cypress wood but in recent years, hives made from injection-molded, dense polystyrene have become increasingly common. Hives also use queen excluders between the brood-box and honey supers to keep the queen from laying eggs in cells next to those containing honey intended for consumption. With the 20th-century advent of mite pests, hive floors are often replaced, either temporarily or permanently, with a wire mesh and a removable tray.
In 2015, the Flow Hive system was invented in Australia by Cedar Anderson and his father Stuart Anderson, whose design allows honey to be extracted without cumbersome centrifuge equipment.
Pioneers of practical and commercial beekeeping
In the 19th century, improvements were made in the design and production of beehives, systems of management and husbandry, stock improvement by selective breeding, honey extraction and marketing. Notable innovators of modern beekeeping include: | Beekeeping | Wikipedia | 463 | 322091 | https://en.wikipedia.org/wiki/Beekeeping | Technology | Forms | null |
Petro Prokopovych used frames with channels in the side of the woodwork; these were packed side-by-side in stacked boxes. Bees traveled between frames and boxes via these channels, which were similar to the cutouts in the sides of modern wooden sections.
Jan Dzierżon' beehive design has influenced modern beehives.
François Huber made significant discoveries about the bee life cycle and communication between bees. Despite being blind, Huber discovered a large amount of information about the queen bee's mating habits and her contact with the rest of the hive. His work was published as New Observations on the Natural History of Bees.
L. L. Langstroth has influenced modern beekeeping practice more than anyone else. His book The Hive and Honey-bee was published in 1853.
Moses Quinby, author of Mysteries of Bee-Keeping Explained, invented the bee smoker in 1873.
Amos Root, author of the A B C of Bee Culture, which has been continuously revised and remains in print, pioneered the manufacture of hives and the distribution of bee packages in the United States.
A. J. Cook author of The Bee-Keepers' Guide; or Manual of the Apiary, 1876.
Dr. C.C. Miller was one of the first entrepreneurs to make a living from apiculture. By 1878, he made beekeeping his sole business activity. His book, Fifty Years Among the Bees, remains a classic and his influence on bee management persists into the 21st century.
Franz Hruschka was an Austrian/Italian military officer who in 1865 invented a simple machine for extracting honey from the comb by means of centrifugal force. His original idea was to support combs in a metal framework and then spin them within a container to collect honey that was thrown out by centrifugal force. This meant honeycombs could be returned to a hive empty and undamaged, saving the bees a vast amount of work, time and materials. This invention significantly improved the efficiency of honey harvesting and catalyzed the modern honey industry.
Walter T. Kelley was an American pioneer of modern beekeeping in the early-and mid-20th century. He greatly improved upon beekeeping equipment and clothing, and went on to manufacture these items and other equipment. His company sold products worldwide and his book How to Keep Bees & Sell Honey, encouraged a boom in beekeeping following World War II. | Beekeeping | Wikipedia | 493 | 322091 | https://en.wikipedia.org/wiki/Beekeeping | Technology | Forms | null |
Cary W. Hartman (1859–1947), lecturer, well known beekeeping enthusiast and honey promoter was elected President of the California State Beekeepers' Association in 1921.
In the UK, practical beekeeping was led in the early 20th century by a few men, pre-eminently Brother Adam and his Buckfast bee, and R.O.B. Manley, author of books including Honey Production in the British Isles and inventor of the Manley frame, which is still universally popular in the UK. Other notable British pioneers include William Herrod-Hempsall and Gale.
Ahmed Zaky Abushady (1892–1955) was an Egyptian poet, medical doctor, bacteriologist, and bee scientist, who was active in England and Egypt in the early twentieth century. In 1919, Abushady patented a removable, standardized aluminum honeycomb. In the same year, he founded The Apis Club in Benson, Oxfordshire, which later became the International Bee Research Association (IBRA). In Egypt in the 1930s, Abushady established The Bee Kingdom League and its organ The Bee Kingdom.
Hives and other equipment
Horizontal hives
A Horizontal top-bar hive is a single-story, frameless beehive in which the comb hangs from removable bars that form a continuous roof over the comb, whereas the frames in most current hives allow space for bees to move between boxes. Hives that have frames or that use honey chambers in summer and use management principles similar to those of regular top-bar hives are sometimes also referred to as top-bar hives. Top-bar hives are rectangular and are typically more than twice as wide as multi-story framed hives commonly found in English-speaking countries. Top-bar hives usually include one box and allow for beekeeping methods that interfere very little with the colony. While conventional advice often recommends inspecting each colony each week during the warmer months, some beekeepers fully inspect top-bar hives only once a year, and only one comb needs to be lifted at a time.
Vertical stackable hives
There are three types of vertical stackable hives: hanging or top-access frame, sliding or side-access frame, and top bar. | Beekeeping | Wikipedia | 451 | 322091 | https://en.wikipedia.org/wiki/Beekeeping | Technology | Forms | null |
Hanging-frame hive designs include Langstroth, the British National, Dadant, Layens, and Rose, which differ in size and number of frames. The Langstroth was the first successful top-opened hive with movable frames. Many other hive designs are based on the principle of bee space that was first described by Langstroth, and is a descendant of Jan Dzierzon's Polish hive designs. Langstroth hives are the most-common size in the United States and much of the world; the British National is the most common size in the United Kingdom; Dadant and Modified Dadant hives are widely used in France and Italy, and Layens by some beekeepers, where their large size is an advantage. Square Dadant hives–often called 12-frame Dadant or Brother Adam hives–are used in large parts of Germany and other parts of Europe by commercial beekeepers.
Any hanging-frame hive design can be built as a sliding frame design. The AZ Hive, the original sliding frame design, integrates hives using Langstroth-sized frames into a honey house to streamline the workflow of honey harvest by localization of labor, similar to cellular manufacturing. The honey house can be a portable trailer, allowing the beekeeper to move hives to a site and provide pollination services.
Top-bar stackable hives use top bars instead of full frames. The most common type is the Warre hive, although any hive with hanging frames can be converted into a top-bar stackable hive by using only the top bar rather than the whole frame. This may work less well with larger frames, where crosscomb and attachment can occur more readily.
Protective clothing
Most beekeepers wear some protective clothing. Novice beekeepers usually wear gloves and a hooded suit or hat and veil. Experienced beekeepers sometimes choose not to use gloves because they inhibit delicate manipulations. The face and neck are the most important areas to protect, so most beekeepers wear at least a veil. Defensive bees are attracted to the breath; a sting on the face can lead to much more pain and swelling than a sting elsewhere, while a sting on a bare hand can usually be quickly removed by fingernail scrape to reduce the amount of venom injected. | Beekeeping | Wikipedia | 464 | 322091 | https://en.wikipedia.org/wiki/Beekeeping | Technology | Forms | null |
Traditionally, beekeeping clothing is pale-colored because of the natural color of cotton and the cost of coloring is an expense not warranted for workwear, though some consider this to provide better differentiation from the colony's natural predators such as bears and skunks, which tend to be dark-colored. It is now known bees see in ultraviolet wavelengths and are also attracted to scent. The type of fabric conditioner used has more impact than the color of the fabric.
Stings that are retained in clothing fabric continue to pump out an alarm pheromone that attracts aggressive action and further stinging attacks. Attraction can be minimized with regular washing.
Smoker
Most beekeepers use a smoker, a device that generates smoke from the incomplete combustion of fuels. Although the exact mechanism is disputed, it is said smoke calms bees. Some claim it initiates a feeding response in anticipation of possible hive abandonment due to fire. It is also thought smoke masks alarm pheromones released by guard bees or bees that are squashed in an inspection. The ensuing confusion creates an opportunity for the beekeeper to open the hive and work without triggering a defensive reaction.
Many types of fuel can be used in a smoker as long as it is natural and not contaminated with harmful substances. Common fuels include hessian, twine, pine needles, corrugated cardboard, and rotten or punky wood. Indian beekeepers, especially in Kerala, often use coconut fibers, which are readily available, safe, and cheap. Some beekeeping supply sources also sell commercial fuels like pulped paper, compressed cotton and aerosol cans of smoke. Other beekeepers use sumac as fuel because it ejects much smoke and lacks an odor.
Some beekeepers use "liquid smoke" as a safer, more convenient alternative. It is a water-based solution that is sprayed onto the bees from a plastic spray bottle. A spray of clean water can also be used to encourage bees to move on. Torpor may also be induced by the introduction of chilled air into the hive, while chilled carbon dioxide may have harmful, long-term effects. | Beekeeping | Wikipedia | 425 | 322091 | https://en.wikipedia.org/wiki/Beekeeping | Technology | Forms | null |
Few anecdotal stories of using the smoke from burning fungi in England or Europe for centuries have been published. Several more recent studies describe anaesthesia of honeybees use of smoke from burning fungi. The fungi reported to have been used to smoke bees are the puffballs Lycoperdon gigantium, L. wahlbergii and the conks, Fomes fomentarius and F. igiarius. When fungi are burned, the characteristic smell is due to the pyrolysis of the keratin cell wall of fungi. Besides being a major fungi constituent, keratin is found in animal tissues, such as hair or feathers. Anaesthesia experiments done using smoke from pyrolysis of L. wahlbergii, human hair and chicken feathers showed no difference in long-term mortality of anesthetized honeybees and non-treated bees in the same hive. Hydrogen sulphide was identified as the major combustion product that is responsible for putting the bees to sleep. Note – hydrogen sulphide is toxic to humans at high concentrations.
Hive tool
Most beekeepers use a hive tool when working on their hives. The two main types are the American hive tool; and the Australian hive tool often called a 'frame lifter'. They are used to scrape off burr-comb from around the hive, especially on top of the frames. They are also used to separate the frames before lifting out of the hive.
Safety and husbandry
Stings
Some beekeepers believe pain and irritation from stings decreases if a beekeeper receives more stings, and they consider it important for safety of the beekeeper to be stung a few times a season. Beekeepers have high levels of antibodies, mainly Immunoglobulin G, caused by a reaction to the major antigen of bee venom, phospholipase A2 (PLA). Antibodies correlate with the frequency of bee stings.
The entry of venom into the body from bee stings may be hindered and reduced by protective clothing that allows the wearer to remove stings and venom sacs with a simple tug on the clothing. Although the stinger is barbed, a worker bee's stinger is less likely to become lodged into clothing than human skin. | Beekeeping | Wikipedia | 461 | 322091 | https://en.wikipedia.org/wiki/Beekeeping | Technology | Forms | null |
Symptoms of being stung include redness, swelling and itching around the site of the sting. In mild cases, pain and swelling subside in two hours. In moderate cases, the red welt at the sting site will become slightly larger for one or two days before beginning to heal. A severe reaction, which is rare among beekeepers, results in anaphylactic shock.
If a beekeeper is stung by a bee, the sting should be removed without squeezing the attached venom glands. A quick scrape with a fingernail is effective and intuitive, and ensures the venom injected does not spread so the side effects of the sting will go away sooner. Washing the affected area with soap and water can also stop the spread of venom. Ice or a cold compress can be applied to the sting area.
Internal temperature of a hive
Bees maintain the internal temperature of their hive at about . Their ability to do this is known as social homeostasis and was first described by Gates in 1914. During hot weather, bees cool the hive by circulating cool air from the entrance through the hive and out again; and if necessary by placing water, which they fetch, throughout the hive to create evaporative cooling. In cold weather, packing and insulation of the bee hive is believed to be beneficial. The extra insulation is believed to reduce the amount of honey the bees consume and makes it easier for them to maintain the hive's temperature. The desire for insulation encouraged the use of double-walled hives with an outer wall of timber or polystyrene; and hives constructed from a ceramic.
Location of hives
There has been considerable debate about the best location for hives. Virgil thought they should be located near clear springs, ponds or shallow brooks. Wildman thought they should face to the south or west. All writers agree hives should be sheltered from strong winds. In hot climates, hives are often placed under the shade of trees in summer. Researchers in the U.S. found domestic honey bees placed in national parks compete with native bee species for resources. A further review of the literature concluded large concentrations of beehives on continents where they are not native, such as North and South America, could compete against the native bees; this, however, was not as strongly observed in areas where domestic bees are native such as Europe and Africa, where the different bee species have adapted to have a narrower overlapping of forage preferences.
Natural beekeeping | Beekeeping | Wikipedia | 492 | 322091 | https://en.wikipedia.org/wiki/Beekeeping | Technology | Forms | null |
The natural beekeeping movement believes bee hives are weakened by modern beekeeping and agricultural practices, such as crop spraying, hive movement, frequent hive inspections, artificial insemination of queens, routine medication, and sugar water feeding. Practitioners of "natural beekeeping" tend to use variations of the top-bar hive, which is a simple design that retains the concept of having a movable comb without the use of frames or a foundation. The horizontal top-bar hive, as promoted by many writers, can be seen as a modernization of hollow log hives, with the addition of wooden bars of specific width from which bees hang their combs. The widespread adoption of Natural Beekeeping methods in recent years can be attributed to the 2007 publications of Natural Beekeeping by Ross Conrad, and The Barefoot Beekeeper by Philip Chandler, which challenges many aspects of modern beekeeping and offers the horizontal top-bar hive as a viable alternative to the ubiquitous Langstroth-style movable-frame hive.
A vertical top-bar hive is the Warré hive, based on a design by the French priest Abbé Émile Warré (1867–1951) and popularized by David Heaf in his English translation of Warré's book L'Apiculture pour Tous as Beekeeping For All.
Urban and backyard beekeeping
Related to natural beekeeping, urban beekeeping is an attempt to revert to a less-industrialized way of obtaining honey by using small-scale colonies that pollinate urban gardens. Some have found city bees are healthier than rural bees because there are fewer pesticides and greater biodiversity in urban gardens. Urban bees may fail to find forage, however, and homeowners can use their land to help feed local bee populations by planting flowers that provide nectar and pollen. An environment of year-round, uninterrupted bloom creates an ideal environment for colony reproduction.
Using managed honeybee colonies to fill the ecological niche of pollinators in urban environments is also thought to be crucial to preventing the formation of feral colonies by more destructive species like the Africanized honeybee (AHB). | Beekeeping | Wikipedia | 425 | 322091 | https://en.wikipedia.org/wiki/Beekeeping | Technology | Forms | null |
Indoor beekeeping
Modern beekeepers have experimented with raising bees indoors in a controlled environment or in indoor observation hives. This may be done for reasons of space and monitoring, or in the cooler months, when large commercial beekeepers may move colonies to "wintering" warehouses with fixed temperature, light, and humidity. This helps bees remain healthy but relatively dormant. These relatively dormant "wintered" bees survive on stored honey, and new bees are not born.
Experiments in raising bees indoors for longer durations have looked into more precise and varying environment controls. In 2015, MIT's "Synthetic Apiary" project simulated springtime inside a closed environment for several hives throughout the winter. They provided food sources and simulated long days, and saw activity and reproduction levels comparable to the levels seen outdoors in warm weather. They concluded such an indoor apiary could be sustained year-round if needed.
Behavior of honey bees
Colony reproduction
Honey bee colonies are dependent on their queen, who is the only egg-layer. Although queens have a three-to-four-year adult lifespan, diminished longevity of queens—less than a year—is commonly and increasingly observed. The queen can choose whether to fertilize an egg as she lays it; fertilized eggs develop into a female worker bees and unfertilized eggs become male drones. The queen's choice of egg type depends on the size of the open brood cell she encounters on the comb. In a small worker cell, she lays a fertilized egg; she lays unfertilized drone eggs in larger drone cells.
When the queen is fertile and laying eggs, she produces a variety of pheromones that control the behavior of the bees in the hive; these are commonly called queen substance. Each pheromone has a different function. As the queen ages, she begins to run out of stored sperm and her pheromones begin to fail. | Beekeeping | Wikipedia | 388 | 322091 | https://en.wikipedia.org/wiki/Beekeeping | Technology | Forms | null |
As the queen's pheromones fail, the bees replace her by creating a new queen from one of her worker eggs. They may do this because she has been physically injured, because she has run out of sperm and cannot lay fertilized eggs, and has become a drone-laying queen, or because her pheromones have dwindled to the point at which they cannot control all of the bees in the hive. At this juncture, the bees produce one or more queen cells by modifying existing worker cells that contain a normal female egg. They then either supersede the queen without swarming or divide the hive into two colonies through swarm-cell production, which leads to swarming.
Supersedure is a valued behavioral trait because hive that supersedes its old queen does not lose any stock; rather it creates a new queen and the old one either naturally dies or is killed when the new queen emerges. In these hives, bees produce only one or two queen cells, most often in the center of the face of a broodcomb. Swarm-cell production involves the creation of twelve or more queen cells. These are large, peanut-shaped protrusions requiring space, for which reason they are often located around the edges—commonly at the sides and the bottom—of the broodcomb.
Once either process has begun, the old queen leaves the hive when the first queen cells hatch, and is accompanied by a large number of bees—predominantly young bees called wax-secretors—which form the basis of the new hive. Scouts are sent from the swarm to find suitable hollow trees or rock crevices; when one is found, the entire swarm moves in. Within hours, the new colony's bees build new wax brood combs using honey stores with which the young bees have filled themselves before leaving the old hive. Only young bees can secrete wax from special abdominal segments, which is why swarms tend to contain more young bees. Often a number of virgin queens accompany the first swarm, known as the "prime swarm", and the old queen is replaced as soon as a daughter queen mates and begins laying. Otherwise, she is quickly superseded in the new hive. | Beekeeping | Wikipedia | 445 | 322091 | https://en.wikipedia.org/wiki/Beekeeping | Technology | Forms | null |
Different sub-species of Apis mellifera exhibit differing swarming characteristics. In North America, northern black races are thought to swarm less and supersede more whereas the southern yellow-and-gray varieties are said to swarm more frequently. Swarming behavior is complicated because of the prevalence of cross-breeding and hybridization of the sub-species. Italian bees are very prolific and inclined to swarm; Northern European black bees have a strong tendency to supersede their old queen without swarming. These differences are the result of differing evolutionary pressures in the regions in which each sub-species evolved.
Factors that trigger swarming
According to George S. Demuth, the main factors that increase the swarming tendency of bees are:
The genetics of bees; the strength of the swarming instinct
Congestion of the brood nest
Insufficient empty combs for ripening nectar and storing honey
Inadequate ventilation
Having an old queen
Warming weather conditions.
Demuth attributed some of his comments to Snelgrove.
Some beekeepers carefully monitor their colonies in spring for the appearance of queen cells, which are a dramatic signal the colony is determined to swarm. After leaving the old hive, the swarm looks for shelter. A beekeeper may capture it and introduce it into a new hive. Otherwise, the swarm reverts to a feral state and finds shelter in a hollow tree or other suitable habitat. A small after-swarm has less chance of survival and may threaten the original hive's survival if the number of remaining bees is unsustainable. When a hive swarms despite the beekeeper's preventative efforts, the beekeeper may give the reduced hive two frames of open brood with eggs. This helps replenish the hive more quickly and gives a second opportunity to raise a queen if there is a mating failure. | Beekeeping | Wikipedia | 360 | 322091 | https://en.wikipedia.org/wiki/Beekeeping | Technology | Forms | null |
Artificial swarming
When a colony accidentally loses its queen, it is said to be queenless. The workers realize the queen is absent after around an hour as her pheromones in the hive fade. Instinctively, the workers select cells containing eggs aged less than three days and dramatically enlarge the cells to form "emergency queen cells". These appear similar to large, -long, peanut-like structures that hang from the center or side of the brood combs. The developing larva in a queen cell is fed differently than an ordinary worker bee; in addition to honey and pollen, she receives a great deal of royal jelly, a special food secreted from the hypopharyngeal gland of young nurse bees. Royal jelly dramatically alters the growth and development of the larva so after metamorphosis and pupation, it emerges from the cell as a queen bee. The queen is the only bee in a colony that has fully developed ovaries; she secretes a pheromone that suppresses the normal development of ovaries in all of her workers.
Beekeepers use the ability of the bees to produce new queens to increase their colonies in a procedure called splitting a colony. To do this, they remove several brood combs from a healthy hive, leaving the old queen behind. These combs must contain eggs or larvae less than three days old and be covered by young nurse bees, which care for the brood and keep it warm. These brood combs and nurse bees are then placed into a small "nucleus hive" with other combs containing honey and pollen. As soon as the nurse bees find themselves in this new hive, and realize they have no queen and begin constructing emergency queen cells using the eggs and larvae in the combs.
Pests and diseases
Diseases
The common agents of disease that affect adult honey bees include fungi, bacteria, protozoa, viruses, parasites and poisons. The gross symptoms displayed by affected adult bees are very similar, whatever the cause, making it difficult to ascertain the causes without microscopic identification of microorganisms or chemical analysis of poisons. Since 2006, colony losses from colony collapse disorder (CCD) have been increasing across the world, although the causes of the syndrome are unknown. In the U.S., commercial beekeepers have been increasing the number of hives to deal with higher rates of attrition. | Beekeeping | Wikipedia | 487 | 322091 | https://en.wikipedia.org/wiki/Beekeeping | Technology | Forms | null |
Parasites
Nosema apis is a microsporidian that causes nosemosis, also called nosema, the most-common and widespread disease of the adult honey bee.
Galleria mellonella and Achroia grisella wax moth larvae hatch, tunnel through and destroy comb that contains bee larvae and their honey stores. The tunnels they create are lined with silk, which entangles and starves emerging bees. Destruction of honeycombs also results in leakage and wasting of honey. A healthy hive can manage wax moths but weak colonies, unoccupied hives and stored frames can be decimated.
Small hive beetle (Aethina tumida) is native to Africa but has now spread to most continents. It is a serious pest among honey bees unadapted to it.
Varroa destructor, the Varroa mite, is an established pest of two species of honey bee through many parts of the world and is blamed by many researchers as a leading cause of CCD.
Tropilaelaps mites, of which there are four species, are native to Apis dorsata, Apis laboriosa, and Apis breviligula, but spread to Apis mellifera after they were introduced to Asia.
Acarapis woodi, the tracheal mite, infests the trachea of honey bees.
Predators
Most predators prefer not to eat honeybees due to their unpleasant sting. Common honeybee predators include large animals such as skunks and bears, which seek the hive's honey and brood, as well as adult bees. Some birds will also eat bees, (for example, bee-eaters, as do some robber flies, such as Mallophora ruficauda, which is a pest of apiculture in South America due to its habit of eating workers while they are foraging in meadows.
Decreasing lifespan
A 2022 study by researchers at University of Maryland, College Park observed lifespan of caged worker bees is half as long as that observed 50 years ago, and hypothesized decreased worker-bee lifespans should correlate to decreased honey production.
Recent developments
World Beekeeping Awards 2024
The World Beekeeping Awards, held in December 2024, showcased the global importance of apiculture and honey production. The event, which took place in London, United Kingdom, featured entries from over 50 countries and highlighted the diverse range of honey varieties produced worldwide. | Beekeeping | Wikipedia | 501 | 322091 | https://en.wikipedia.org/wiki/Beekeeping | Technology | Forms | null |
Honey fraud scandal
However, the 2024 World Beekeeping Awards were marred by a significant scandal involving honey fraud. Investigators uncovered a sophisticated operation where some contestants had submitted adulterated honey samples.
The fraudulent entries contained:
Honey diluted with sugar syrup
Mislabeled honey varieties
Honey from undisclosed geographical origins
This incident has raised concerns about the integrity of honey production and labeling practices in the global market. As a result, the World Beekeeping Association has announced plans to implement more rigorous testing procedures for future competitions.
Industry response
In response to the fraud scandal, several measures have been proposed to enhance honey authenticity and protect consumers:
Advanced testing methods: Implementation of more sophisticated laboratory techniques to detect adulteration.
Blockchain technology: Exploration of blockchain-based traceability systems to track honey from hive to shelf.
Stricter regulations: Calls for more stringent international standards and enforcement of honey labeling and production practices.
These developments highlight the ongoing challenges faced by the beekeeping industry in maintaining product integrity and consumer trust in an increasingly global market.
World apiculture
According to Food and Agriculture Organization data, the world's beehive stock rose from around 50 million in 1961 to around 83 million in 2014, which represents an annual average growth of 1.3%. Average annual growth has accelerated to 1.9% since 2009.
Gallery: Harvesting honey | Beekeeping | Wikipedia | 267 | 322091 | https://en.wikipedia.org/wiki/Beekeeping | Technology | Forms | null |
Mangosteen (Garcinia mangostana), also known as the purple mangosteen, is a tropical evergreen tree with edible fruit native to Island Southeast Asia, from the Malay Peninsula to Borneo. It has been cultivated extensively in tropical Asia since ancient times. It is grown mainly in Southeast Asia, southwest India and other tropical areas such as Colombia, Puerto Rico and Florida, where the tree has been introduced. The tree grows from tall.
The fruit of the mangosteen is sweet and tangy, juicy, somewhat fibrous, with fluid-filled vesicles (like the flesh of citrus fruits), with an inedible, deep reddish-purple colored rind (exocarp) when ripe. In each fruit, the fragrant edible flesh that surrounds each seed is botanically endocarp, i.e., the inner layer of the ovary. The seeds are of similar size and shape to almonds.
Genus Garcinia also contains several less-known fruit-bearing species, such as the button mangosteen (G. prainiana) and the charichuelo (G. madruno).
Description
Tree
A tropical tree, the mangosteen must be grown in consistently warm conditions, as exposure to temperatures below for prolonged periods will usually kill a mature plant. They are known to recover from brief cold spells rather well, often with damage only to young growth. Experienced horticulturists have grown this species outdoors, and brought them to fruit in extreme south Florida.
The tree grows from tall.
Fruit
The juvenile mangosteen fruit, which does not require fertilisation to form (see agamospermy), first appears as pale green or almost white in the shade of the canopy. As the fruit enlarges over the next two to three months, the exocarp colour deepens to darker green. During this period, the fruit increases in size until its exocarp is in outside diameter, remaining hard until a final, abrupt ripening stage.
The subsurface chemistry of the mangosteen exocarp comprises an array of polyphenols, including xanthones and tannins that assure astringency which discourages infestation by insects, fungi, plant viruses, bacteria, and animal predation while the fruit is immature. Colour changes and softening of the exocarp are natural processes of ripening that indicate the fruit can be eaten and the seeds have finished developing. | Mangosteen | Wikipedia | 506 | 322105 | https://en.wikipedia.org/wiki/Mangosteen | Biology and health sciences | Other culinary fruits | Plants |
Once the developing mangosteen fruit has stopped expanding, chlorophyll synthesis slows as the next colour phase begins. Initially streaked with red, the exocarp pigmentation transitions from green to red to dark purple, indicating a final ripening stage. This entire process takes place over a period of ten days as the edible quality of the fruit peaks. Over the days following removal from the tree, the exocarp hardens to an extent depending upon post-harvest handling and ambient storage conditions, especially relative humidity levels. If the ambient humidity is high, exocarp hardening may take a week or longer when the flesh quality is peaking and excellent for consumption. However, after several additional days of storage, especially if unrefrigerated, the flesh inside the fruit might spoil without any obvious external indications. Using the hardness of the rind as an indicator of freshness for the first two weeks following harvest is therefore unreliable because the rind does not accurately reveal the interior condition of the flesh. If the exocarp is soft and yielding as it is when ripe and fresh from the tree, the fruit is usually good.
The edible endocarp of the mangosteen has the same shape and size as a tangerine in diameter, but is white. The number of fruit segments corresponds exactly with the number of stigma lobes on the exterior apex; accordingly, a higher number of fleshy segments also corresponds with the fewest seeds. The circle of wedge-shaped segments contains 4–8, rarely 9 segments, the larger ones harbouring the apomictic seeds that are unpalatable unless roasted. As a non-climacteric fruit, picked mangosteen does not ripen further, so it must be consumed shortly after harvest.
Often described as a subtle delicacy, the flesh bears an exceptionally mild aroma, quantitatively having about 1/400th of the chemical constituents of fragrant fruits, explaining its relative mildness. The main volatile components having caramel, grass and butter notes as part of the mangosteen fragrance are hexyl acetate, hexenol and α-copaene. Ethyl octanoate, ethyl hexanoate and 3-methyl-2-butene-1-thiol were detected as aroma components in mangosteen wine. | Mangosteen | Wikipedia | 469 | 322105 | https://en.wikipedia.org/wiki/Mangosteen | Biology and health sciences | Other culinary fruits | Plants |
Origins and history
Cultivated mangosteen (Garcinia mangostana var. mangostana) is dioecious, but male trees are unknown. The trees produce viable seeds via apomixis, where all the embryos are essentially clones of the mother. Its extensive cultivation has made its original native range difficult to ascertain. Garcinia mangostana var. mangostana is likely to be the domesticated descendant of wild populations of Garcinia mangostana var. malaccensis (previously thought to be a separate species) and Garcinia mangostana var. borneensis, native to the Malay Peninsula and Borneo respectively. Both of these wild varieties still possess male trees, unlike the domesticated mangosteen. It may have also hybridized to a limited extent with closely-related species, including Garcinia penangiana and Garcinia venulosa.
Mangosteen is highly valued for its juicy, delicate texture and slightly sweet and sour flavor, the mangosteen has been cultivated in Malaysia, Borneo, Sumatra, Mainland Southeast Asia, and the Philippines since ancient times. The 15th-century Chinese record Yingya Shenglan described mangosteen as mang-chi-shih (derived from Malay manggis), a native plant of Southeast Asia of white flesh with a delectable sweet and sour taste.
A description of mangosteen was included in the Species Plantarum by Linnaeus in 1753. The mangosteen was introduced into English greenhouses in 1855. Subsequently, its culture was introduced into the Western Hemisphere, where it became established in West Indies islands, especially Jamaica. It was later established on the Americas mainland in Guatemala, Honduras, Panama, and Ecuador. The mangosteen tree generally does not grow well outside the tropics.
In Southeast Asia, mangosteen is commonly known as the "Queen of Fruits", and is frequently paired with durian, the "King of Fruits". In Chinese food therapy, mangosteen is considered "cooling", making it a good counterbalance to the "heaty" durian. There is also a legend about Queen Victoria offering a reward of one hundred pounds sterling to anyone who could deliver a fresh mangosteen to her. Although this legend can be traced to a 1930 publication by the fruit explorer David Fairchild, it is not substantiated by any known historical document. | Mangosteen | Wikipedia | 486 | 322105 | https://en.wikipedia.org/wiki/Mangosteen | Biology and health sciences | Other culinary fruits | Plants |
The journalist and gourmet R. W. Apple Jr. once said of the fruit, "No other fruit, for me, is so thrillingly, intoxicatingly luscious...I'd rather eat one than a hot fudge sundae, which for a big Ohio boy is saying a lot." Since 2006, private small-volume orders for fruits grown in Puerto Rico were sold to American specialty food stores and gourmet restaurants who serve the flesh segments as a delicacy dessert.
Propagation, cultivation and harvest
Mangosteen is usually propagated by seedlings. Vegetative propagation is difficult and seedlings are more robust and reach fruiting earlier than vegetatively propagated plants.
Mangosteen produces a recalcitrant seed which is not a true seed strictly defined, but rather described as a nucellar asexual embryo. As seed formation involves no sexual fertilization, the seedling is genetically identical to the mother plant. If allowed to dry, a seed dies quickly, but if soaked, seed germination takes between 14 and 21 days when the plant can be kept in a nursery for about 2 years growing in a small pot.
When the trees are approximately , they are transplanted to the field at a spacing of . After planting, the field is mulched in order to control weeds. Transplanting takes place in the rainy season because young trees are likely to be damaged by drought. Because young trees need shade, intercropping with banana, plantain, rambutan, durian or coconut leaves is effective. Coconut palms are mainly used in areas with a long dry season, as palms also provide shade for mature mangosteen trees. Another advantage of intercropping in mangosteen cultivation is the suppression of weeds.
The growth of the trees is retarded if the temperature is below . The ideal temperature range for growing and producing fruits is with relative humidity over 80%. The maximal temperature is , with both leaves and fruit being susceptible to scorching and sunburn, while the minimum temperature is . Young seedlings prefer a high level of shade and mature trees are shade-tolerant. | Mangosteen | Wikipedia | 445 | 322105 | https://en.wikipedia.org/wiki/Mangosteen | Biology and health sciences | Other culinary fruits | Plants |
Mangosteen trees have a weak root system and prefer deep, well-drained soils with high moisture content, often growing on riverbanks. The mangosteen is not adapted to limestone soils, sandy, alluvial soils, or sandy soils with low organic matter content. Mangosteen trees need a well-distributed rainfall over the year (<40 mm/month) and a 3–5 week dry season.
Mangosteen trees are sensitive to water availability and application of fertilizer input which is increased with the age of trees, regardless of region. Maturation of mangosteen fruits takes 5–6 months, with harvest occurring when the pericarps are purple.
Breeding
In the breeding of perennial mangosteen, the selection of rootstock and grafting are significant issues to overcome constraints to production, harvesting, or seasonality. Most of the genetic resources for breeding are in germplasm collections, whereas some wild species are cultivated in Malaysia and the Philippines. Conservation methods are chosen because storage of seeds under dried and low-temperature conditions has not been successful.
Because of the long duration until the trees yield fruits and the long resulting breeding cycles, mangosteen breeding has not proven attractive for transplanting or research. Breeding objectives that may enhance mangosteen production include:
Drought tolerance, especially sensitivity to drought in the first 5 years after germination
Tree architecture to produce a tree with a crown that is regular and pyramid-shaped
Fruit quality including i) overcoming bitter taste components caused by changes in pulp, pericarp or aril and ii) pericarp cracking resulting from excessive water uptake
Rootstock for improved adaptation to drought and robust development in early years of growth
Yield
Mangosteen trees may reach fruit-bearing in as little as 6 years but may require 12 or more years, depending on climate and cultivation methods. The yield of the mangosteen is variable, depending on the climate and age of the tree. If the young tree is bearing for the first time, 200–300 fruits may be produced, whereas at maturity, 500 fruits per season are average. At age 30 to 45 years in full maturity, each tree may yield as many as 3,000 fruits, with trees as old as 100 years still producing. | Mangosteen | Wikipedia | 456 | 322105 | https://en.wikipedia.org/wiki/Mangosteen | Biology and health sciences | Other culinary fruits | Plants |
Regional production
Major mangosteen production occurs in Southeast Asia, mainly in Thailand as the country with the most acreage planted, estimated at 4,000 ha in 1965 and 11,000 ha in 2000, giving a total yield of 46,000 tons. Mangosteen is seasonally available in Thailand from May through September. Indonesia, Malaysia and the Philippines are other major Asian producers. Mangosteen production in Colombia and Puerto Rico has been successful.
Diseases and pests
Common diseases and pests
The pathogens that attack mangosteen are common in other tropical trees. The diseases can be divided into foliar, fruit, stem and soil-borne diseases.
Pestalotiopsis leaf blight (Pestalotiopsis flagisettula (only identified in Thailand)) is one of the diseases that infect especially young leaves. Furthermore, the pathogen causes the fruits to rot before and after the harvest. Additional stem canker and dieback are caused by the pathogen. Some of the symptoms of stem canker are branch splitting, gummosis and bark blistering. The main areas where the disease was observed are Thailand, Malaysia, and North Queensland.
Another common disease is the thread blight or white thread blight disease (Marasmiellus scandens) whereas the name comes from the mycelia which resembles thread. Leaves, twigs, and branches may also be damaged by the disease. The spores spread with the help of wind, raindrops, and insects, and thrive in shady, humid, and wet conditions.
An important post-harvest disease affecting mangosteen, especially in Thailand is called Diplodia fruit rot (Diplodia theobromae) which, as a secondary pathogen, enters the host plant through wounds.
Phellinus noxius living on the roots and trunk bases causes brown root disease, a name derived from the appearance of the mycelium-binding soil particles. The distribution of the fungus happens through contact with infected wood or thick rhizomorphs on tree stumps. | Mangosteen | Wikipedia | 413 | 322105 | https://en.wikipedia.org/wiki/Mangosteen | Biology and health sciences | Other culinary fruits | Plants |
There are a few pests that feed on mangosteen leaves and fruits including leaf eater (Stictoptera sp.), leaf miner (Phyllocnictis citrella) and fruit borer (Curculio sp.). Especially in nurseries, the larval stage of the leaf eater can cause visible damage on young leaves, but can be managed by biological control agents. The larval stage of fruit borer (Curculio sp.) feeds on different parts of fruit before ripening.
Control measures for diseases and pests
Different management options can be applied to control mangosteen diseases.
Measures to inhibit sun scalding to minimize leaf blight and stem canker.
Reduction of wounds caused by insects and storm damage to minimize disease incidence.
Change of the microclimate by tree spacing and pruning.
Chemicals applied to root collars and tree stumps to control root diseases.
Fungicides to control fungal pathogens.
Biological pest control or insecticides to control insects.
Nutritional content
The endocarp the white part of the fruit having a mild flavor is edible, but its nutrition content is modest, as all nutrients analyzed are at a low percentage of the Daily Value (see table for canned fruit in syrup, USDA FoodData Central; note that nutrient values for fresh fruit are likely different, but have not been published by a reputable source).
Uses
Culinary
Without fumigation or irradiation (to kill the Asian fruit fly), fresh mangosteens were illegal to import into the United States until 2007. Following export from its natural growing regions in Southeast Asia (particularly Thailand), the fresh fruit is available seasonally in some local markets in North America such as those of Chinatowns. Mangosteens are available fresh, canned and frozen in Western countries. The fruit may be served as a dessert or made into jams. In Vietnam, the ripe fruit is also used as a salad ingredient.
Upon arrival in the US in 2007, fresh mangosteens sold at up to in specialty produce stores in New York City, but wider availability and somewhat lower prices have become common in the United States and Canada. Despite efforts described above to grow mangosteen in the Western Hemisphere, nearly the entire supply is imported from Thailand. | Mangosteen | Wikipedia | 462 | 322105 | https://en.wikipedia.org/wiki/Mangosteen | Biology and health sciences | Other culinary fruits | Plants |
Before ripening, the mangosteen shell is fibrous and firm but becomes soft and easy to pry open when the fruit ripens. To open a mangosteen, the shell can be scored with a knife, pried gently along the score with the thumbs until it cracks, and then pulled apart to reveal the fruit. Alternatively, the mangosteen can be opened without a knife by squeezing the shell from the bottom until it breaks, allowing the shell to be removed and the fruit eaten while intact with the stem. In Southeast Asian countries, the mangosteen is usually served with the bottom part of the shell intact. Occasionally, during peeling of ripe fruits, the purple exocarp juice may stain skin or fabric.
Traditional medicine
Various parts of the plant have a history of use in traditional medicine, mostly in Southeast Asia; it may have been used to treat skin infections, wounds, dysentery, urinary tract infections, and gastrointestinal complaints, although there is no high-quality clinical evidence for any of these effects.
Dried fruits are shipped to Singapore to be processed for medical uses which may include dysentery, skin disorders, and various other minor diseases in several countries across Asia. There is no reliable evidence that mangosteen juice, puree, bark or extracts is effective as a treatment for human diseases.
Natural dye
The extract of mangosteen peels is traditionally used in Indonesia as natural dye for coloring of brown, dark brown, purple or red hues applied to tenun ikat and batik textiles.
Other uses
Mangosteen twigs have been used as chew sticks in Ghana, and the wood has been used to make spears and cabinetry in Thailand. The rind of the mangosteen fruit has also been used to tan leather in China.
Phytochemicals
Mangosteen peel contains xanthonoids, such as mangostin, and other phytochemicals.
Polysaccharide and xanthone compounds are found in the fruit, leaves, and heartwood of the mangosteen. Fully ripe fruit contain the xanthones gartanin, 8-disoxygartanin, and normangostin. | Mangosteen | Wikipedia | 447 | 322105 | https://en.wikipedia.org/wiki/Mangosteen | Biology and health sciences | Other culinary fruits | Plants |
Marketing
Fresh mangosteen is marketed for only a short period of six to ten weeks due to its seasonal nature. It is mainly grown by smallholders and sold at fruit stalls by roadsides. Its irregular, short supply leads to wide price fluctuations throughout its season and over the years. Additionally, there is no standard product quality assessment or grading system, making international trade of the fruit difficult. The mangosteen still remains rare in Western markets, though its popularity is increasing, and it is often sold at a high price. | Mangosteen | Wikipedia | 105 | 322105 | https://en.wikipedia.org/wiki/Mangosteen | Biology and health sciences | Other culinary fruits | Plants |
Penile cancer, or penile carcinoma, is a cancer that develops in the skin or tissues of the penis. Symptoms may include abnormal growth, an ulcer or sore on the skin of the penis, and bleeding or foul smelling discharge.
Risk factors include phimosis (inability to retract foreskin of the penis), chronic inflammation, smoking, HPV infection, condylomata acuminate, having multiple sexual partners, and early age of sexual intercourse.
Around 95% of penile cancers are squamous-cell carcinomas. Other types of penile cancer such as Merkel-cell carcinoma, small-cell carcinoma, and melanoma are generally rare. In 2020, it occurred in 36,000 men and caused 13,000 deaths.
Signs and symptoms
Penile cancer can present as redness and irritation on the penis with a skin thickening on the glans or inner foreskin or an ulcerative, outward growing (exophytic) or “finger-like” (papillary) growth. Penile cancer may accompany penile discharge with or without difficulty or burning or tingling while urinating (dysuria) and bleeding from the penis.
Risk factors
Infections
HIV infection—HIV-positive men have eight-fold increased risk of developing penile cancer than HIV-negative men.
Human papillomavirus—HPV is a risk factor in the development of penile cancer. According to the Centers for Disease Control and Prevention (CDC), HPV is responsible for about 800 (about 40%) of 1,570 cases of penile cancer diagnosed annually in the United States. There are more than 120 types of HPV.
Genital warts—Genital or perianal warts increase the risk of invasive penile cancer by about 3.7 times if they occurred more than two years before the reference date. About half of men with penile cancer also have genital warts, which are caused by HPV. | Penile cancer | Wikipedia | 410 | 322177 | https://en.wikipedia.org/wiki/Penile%20cancer | Biology and health sciences | Cancer | Health |
Hygiene and injury
Poor hygiene—Poor hygiene can increase a man's risk of penile cancer.
Smegma—Smegma, a whitish substance that can accumulate beneath the foreskin, is associated with greater risk of penile cancer. The American Cancer Society suggests that smegma may not be carcinogenic, but may increase the risk by causing irritation and inflammation of the penis.
Balanitis and penile injury—Inflammation of the foreskin and/or the glans penis (balanitis) is associated with about 3.1 times increased risk of penile cancer. It is usually caused by poor hygiene, allergic reactions to certain soaps, or an underlying health condition such as reactive arthritis, infection, or diabetes. Small tears and abrasions of the penis are associated with about 3.9 times increased risk of cancer.
Phimosis—Phimosis is a medical condition where the foreskin cannot be fully retracted over the glans. It is considered a significant risk factor in the development of penile cancer (odds ratio of 38–65). Phimosis may also be a symptom of penile cancer.
Paraphimosis—Paraphimosis is a medical condition where the foreskin becomes trapped behind the glans. It is considered a risk factor for the development of penile cancer.
Circumcision—Some studies show that circumcision during infancy or in childhood may provide partial protection against penile cancer, but this is not the case when performed in adulthood. It has been suggested that the reduction in risk may be due to reduced risk of phimosis; other possible mechanisms include reduction in risk of smegma and HPV infection.
Other
Age—Penile cancer is rarely seen in men under the age of 50. About 4 out of 5 men diagnosed with penile cancer are over the age of 55.
Lichen sclerosus—Lichen sclerosus is a disease causing white patches on the skin. Lichen sclerosus increases the risk of penile cancer. As the exact cause of lichen sclerosus is unknown, there is no known way to prevent it.
Tobacco—Chewing or smoking tobacco increases the risk of penile cancer by 1.5–6 times depending on the duration smoking and daily number of cigarettes.
Ultraviolet light—Men with psoriasis who have been treated using UV light and a drug known as psoralen have an increased risk of penile cancer. | Penile cancer | Wikipedia | 506 | 322177 | https://en.wikipedia.org/wiki/Penile%20cancer | Biology and health sciences | Cancer | Health |
Pathogenesis
Penile cancer arises from precursor lesions, which generally progress from low-grade to high-grade lesions. For HPV related penile cancers this sequence is as follows:
Squamous hyperplasia;
Low-grade penile intraepithelial neoplasia (PIN);
High-grade PIN (carcinoma in situ—Bowen's disease, Erythroplasia of Queyrat and bowenoid papulosis (BP));
Invasive carcinoma of the penis.
However, in some cases, non-dysplastic or mildly dysplastic lesions may progress directly into cancer. Examples include flat penile lesions (FPL) and condylomata acuminata.
In HPV negative cancers, the most common precursor lesion is lichen sclerosus (LS).
Diagnosis
The International Society of Urological Pathology (ISUP) recommends the use of p16INK4A immunostaining for the diagnosis and classification of HPV-related penile cancer.
Classification
Around 95% of penile cancers are squamous-cell carcinomas. They are classified into the following types:
basaloid (4%)
warty (6%)
mixed warty-basaloid (17%)
verrucous (8%)
papillary (7%)
other SCC mixed (7%)
sarcomatoid carcinomas (1%)
not otherwise specified (49%)
Other types of carcinomas are rare and may include small-cell, Merkel-cell, clear-cell, sebaceous-cell or basal-cell tumors. Non-epithelial malignancies such as melanomas and sarcomas are even more rare.
Staging
Like many malignancies, penile cancer can spread to other parts of the body. It is usually a primary malignancy, the initial place from which cancer spreads in the body. Much less often it is a secondary malignancy, one in which the cancer has spread to the penis from elsewhere. The staging of penile cancer is determined by the extent of tumor invasion, nodal metastasis, and distant metastasis. | Penile cancer | Wikipedia | 450 | 322177 | https://en.wikipedia.org/wiki/Penile%20cancer | Biology and health sciences | Cancer | Health |
The T portion of the AJCC TNM staging guidelines are for the primary tumor as follows:
TX: Primary tumor cannot be assessed.
T0: No evidence of primary tumor.
Tis: Carcinoma in situ.
Ta: Noninvasive verrucous carcinoma.
T1a: Tumor invades subepithelial connective tissue without lymph vascular invasion and is not poorly differentiated (i.e., grade 3–4).
T1b: Tumor invades subepithelial connective tissue with lymph vascular invasion or is poorly differentiated.
T2: Tumor invades the corpus spongiosum or cavernosum.
T3: Tumor invades the urethra or prostate.
T4: Tumor invades other adjacent structures.
Anatomic Stage or Prognostic Groups of penile cancer are as follows:
Stage 0—Carcinoma in situ.
Stage I—The cancer is moderately or well-differentiated and only affects the subepithelial connective tissue.
Stage II—The cancer is poorly differentiated, affects lymphatics, or invades the corpora or urethra.
Stage IIIa—There is deep invasion into the penis and metastasis in one lymph node.
Stage IIIb—There is deep invasion into the penis and metastasis into multiple inguinal lymph nodes.
Stage IV—The cancer has invaded into structures adjacent to the penis, metastasized to pelvic nodes, or distant metastasis is present.
HPV positive tumors
Human papillomavirus prevalence in penile cancers is high at about 40%. HPV16 is the predominant genotype accounting for approximately 63% of HPV-positive tumors. Among warty/basaloid cancers the HPV prevalence is 70–100% while in other types it is around 30%. | Penile cancer | Wikipedia | 382 | 322177 | https://en.wikipedia.org/wiki/Penile%20cancer | Biology and health sciences | Cancer | Health |
Prevention
HPV vaccines such as Gardasil or Cervarix may reduce the risk of HPV and, consequently, penile cancer.
The use of condoms is thought to be protective against HPV-associated penile cancer.
Good genital hygiene, which involves washing the penis, the scrotum, and the foreskin daily with water, may prevent balanitis and penile cancer. However, soaps with harsh ingredients should be avoided.
Cessation of smoking may reduce the risk of penile cancer.
Circumcision during infancy or in childhood may provide partial protection against penile cancer. Several authors have proposed circumcision as a possible strategy for penile cancer prevention; however, the American Cancer Society points to the rarity of the disease and notes that neither the American Academy of Pediatrics nor the Canadian Academy of Pediatrics recommend routine neonatal circumcision.
Phimosis can be prevented by practising proper hygiene and by retracting the foreskin on a regular basis.
Paraphimosis can be prevented by not leaving the foreskin retracted for prolonged periods of time.
Treatment
Treatment of penile cancer will vary depending on the clinical stage of the tumor at the time of diagnosis. There are several treatment options for penile cancer, depending on staging. They include surgery, radiation therapy, chemotherapy, and biological therapy. The most common treatment is one of five types of surgery:
Wide local excision—the tumor and some surrounding healthy tissue are removed
Microsurgery—surgery performed with a microscope is used to remove the tumor and as little healthy tissue as possible
Laser surgery—laser light is used to burn or cut away cancerous cells
Circumcision—cancerous foreskin is removed
Amputation (penectomy)—a partial or total removal of the penis, and possibly the associated lymph nodes.
The role of radiation therapy includes an organ-sparing approach for early-stage penile cancer at specialized centres. Furthermore, adjuvant therapy is used for patients with locally advanced disease or for symptom management.
Prognosis
Prognosis can range considerably for patients, depending where on the scale they have been staged. Generally speaking, the earlier the cancer is diagnosed, the better the prognosis. The overall 5-year survival rate for all stages of penile cancer is about 50%. | Penile cancer | Wikipedia | 478 | 322177 | https://en.wikipedia.org/wiki/Penile%20cancer | Biology and health sciences | Cancer | Health |
Epidemiology
Penile cancer is a rare cancer in developed nations, with annual incidence varying from 0.3 to 1 per 100,000 per year, accounting for around 0.4–0.6% of all malignancies. The annual incidence is approximately 1 in 100,000 men in the United States, 1 in 250,000 in Australia, and 0.82 per 100,000 in Denmark. In the United Kingdom, fewer than 500 men are diagnosed with penile cancer every year.
In the developing world, penile cancer is much more common. For instance, in Paraguay, Uruguay, Uganda and Brazil the incidence is 4.2, 4.4, 2.8 and 1.5–3.7 per 100,000, respectively. In some South American countries, Africa, and Asia, this cancer type constitutes up to 10% of malignant diseases in men.
the lifetime risk was estimated as 1 in 1,437 in the United States and 1 in 1,694 in Denmark. | Penile cancer | Wikipedia | 207 | 322177 | https://en.wikipedia.org/wiki/Penile%20cancer | Biology and health sciences | Cancer | Health |
Tension headache, stress headache, or tension-type headache (TTH), is the most common type of primary headache. The pain usually radiates from the lower back of the head, the neck, the eyes, or other muscle groups in the body typically affecting both sides of the head. Tension-type headaches account for nearly 90% of all headaches.
Pain medications, such as paracetamol and ibuprofen, are effective for the treatment of tension headache. Tricyclic antidepressants appear to be useful for prevention. Evidence is poor for SSRIs, propranolol and muscle relaxants.
The 2016 Global Burden of Disease study revealed that TTHs affect about 1.89 billion people and are more common in women than men (30.8% to 21.4% respectively). TTH was most prevalent between ages 35 and 39. Despite its benign character, tension-type headache, especially in its chronic form, can impart significant disability on patients as well as burden on society at large. In 2016, the global burden of TTH was reported to be 7.2 million years of life lived with disability (YLDs). The YLD was calculated using TTH prevalence and average time spent with TTH multiplied by percentage health loss caused by TTH (3.7%).
Signs and symptoms
According to the third edition of the International Classification of Headache Disorders, the attacks must meet the following criteria:
A duration of between 30 minutes and 7 days.
At least two of the following four characteristics:
bilateral location
pressing or tightening (non-pulsating) quality
mild or moderate intensity
not aggravated by routine physical activity such as walking or climbing stairs
Both of the following:
no nausea or vomiting
no more than one of photophobia (sensitivity to bright light) or phonophobia (sensitivity to loud sounds)
Tension-type headaches may be accompanied by tenderness of the scalp on manual pressure during an attack.
Risk factors
Various precipitating factors may cause tension-type headaches in susceptible individuals:
Anxiety
Stress
Sleep problems
Young age
Poor health | Tension headache | Wikipedia | 424 | 322197 | https://en.wikipedia.org/wiki/Tension%20headache | Biology and health sciences | Specific diseases | Health |
Mechanism
Although the musculature of the head and neck and psychological factors such as stress may play a role in the overall pathophysiology of TTH, neither is currently believed to be the sole cause of the development of TTH. The pathologic basis of TTH is most likely derived from a combination of personal factors, environmental factors, and alteration of both peripheral and central pain pathways. Peripheral pain pathways receive pain signals from pericranial (around the head) myofascial tissue (protective tissue of muscles) and alteration of this pathway likely underlies episodic tension-type headache (ETTH). In addition, pericranial muscle tenderness, inflammation, and muscle ischemia have been postulated in headache literature to be causal factors in the peripheral pathophysiology of TTH. However, multiple studies have failed to illustrate evidence for a pathologic role of either ischemia or inflammation within the muscles. Pericranial tenderness is also not likely a peripheral causal factor for TTH, but may instead act to trigger a chronic pain cycle. This is when the peripheral pain response is transformed over time into a centralized pain response. These prolonged alterations in the peripheral pain pathways can lead to increased excitability of the central nervous system pain pathways, resulting in the transition of ETTH into chronic tension-type headache (CTTH). Specifically, the hyperexcitability occurs in central nociceptive neurons (the trigeminal spinal nucleus, thalamus, and cerebral cortex) resulting in central sensitization, which manifests clinically as allodynia and hyperalgesia of CTTH. Additionally, CTTH patients exhibit decreased thermal and pain thresholds which further bolsters support for central sensitization occurring in CTTH.
The alterations in physiology that leads to the overall process of central sensitization, involves changes at the level of neural tracts, neurotransmitters and their receptors, the neural synapse, and the post-synaptic membrane. Evidence also suggests that dysfunction in supraspinal descending inhibitory pain pathways may contribute to the pathogenesis of central sensitization in CTTH.
Neurotransmitters | Tension headache | Wikipedia | 453 | 322197 | https://en.wikipedia.org/wiki/Tension%20headache | Biology and health sciences | Specific diseases | Health |
Specific neuronal receptors and neurotransmitters thought to be most involved include NMDA and AMPA receptors, glutamate, serotonin (5-HT), β-endorphin, and nitric oxide (NO). Of the neurotransmitters, NO plays a major role in central pain pathways and likely contributes to the process of central sensitization. Briefly, the enzyme nitric oxide synthase (NOS) forms NO which ultimately results in vasodilatation and activation of central nervous system pain pathways. Serotonin may also be of significant importance and involved in malfunctioning pain filter located in the brain stem. The view is that the brain misinterprets information—for example from the temporal muscle or other muscles—and interprets this signal as pain. Evidence for this theory comes from the fact that chronic tension-type headaches may be successfully treated with certain antidepressants such as nortriptyline. However, the analgesic effect of nortriptyline, as well as amitriptyline in chronic tension-type headache, is not solely due to serotonin reuptake inhibition, and likely other mechanisms are involved.
Synapses
Regarding synaptic level changes, homosynaptic facilitation and heterosynaptic facilitation are both likely to be involved in central sensitization. Homosynaptic facilitation occurs when synapses normally involved in pain pathways undergo changes involving receptors on the post-synaptic membrane as well as the molecular pathways activated upon synaptic transmission. Lower pain thresholds of CTTH result from this homosynaptic facilitation. In contrast, heterosynaptic facilitation occurs when synapses not normally involved in pain pathways become involved. Once this occurs innocuous signals are interpreted as painful signals. Allodynia and hyperalgesia of CTTH represent this heterosynaptic facilitation clinically.
Stress
In the literature, stress is mentioned as a factor and may be implicated via the adrenal axis. This ultimately results in downstream activation of NMDA receptor activation, NFκB activation, and upregulation of iNOS with subsequent production of NO leading to pain as described above. | Tension headache | Wikipedia | 475 | 322197 | https://en.wikipedia.org/wiki/Tension%20headache | Biology and health sciences | Specific diseases | Health |
Diagnosis
With TTH, the physical exam is expected to be normal with perhaps the exception of either pericranial tenderness upon palpation of the cranial muscles, or presence of either photophobia or phonophobia.
Classification
The International Headache Society's most current classification system for headache disorders is the International Classification of Headache Disorders 3rd edition (ICHD-3) as of 2018. This classification system separates tension-type headache (TTH) into two main groups: episodic (ETTH) and chronic (CTTH). CTTH is defined as fifteen days or more per month with headache for greater than three months, or one-hundred eighty days or more, with headache per year. ETTH is less than fifteen days per month with headache or less than one-hundred eighty days with headache per year. However, ETTH is further sub-divided into frequent and infrequent TTH. Frequent TTH is defined as ten or more episodes of headache over the course of one to fourteen days per month for greater than three months, or at least twelve days per year, but less than one-hundred eighty days per year. Infrequent TTH is defined as ten or more episodes of headache for less than one day per month or less than twelve days per year. Furthermore, all sub-classes of TTH can be classified as having presence or absence of pericranial tenderness, which is tenderness of the muscles of the head. Probable TTH is utilized for patients with some characteristics, but not all characteristics of a given sub-type of TTH.
Differential diagnosis
Extensive testing is not needed as TTH is diagnosed by history and physical examination. However, if symptoms indicative of a more serious diagnosis are present, a contrast enhanced MRI may be utilized. Furthermore, giant cell arteritis should be considered in those 50 years of age and beyond. Screening for giant cell arteritis involves the blood tests of erythrocyte sedimentation rate (ESR) and c-reactive protein.
Migraine
Oromandibular dysfunction
Sinus disease
Eye disease
Cervical spine disease
Infection in immunocompromised
Intracranial mass
Idiopathic intracranial hypertension
Medication overuse headache
Secondary headache (headache due to other disorder)
Giant cell arteritis (≥50 years of age)
Dermatochalasis
Prevention
Lifestyle
Good posture might prevent headaches if there is neck pain.
Drinking alcohol can make headaches more likely or severe. | Tension headache | Wikipedia | 499 | 322197 | https://en.wikipedia.org/wiki/Tension%20headache | Biology and health sciences | Specific diseases | Health |
Drinking water and avoiding dehydration helps in preventing tension headache.
People who have jaw clenching might develop headaches, and getting treatment from a dentist might prevent those headaches.
Using stress management and relaxing often makes headaches less likely.
Biofeedback techniques may also help.
Medications
People who have 15 or more headaches in a month may be treated with certain types of daily antidepressants which act to prevent continued tension headaches from occurring. In those who are predisposed to tension type headaches the first-line preventative treatment is amitriptyline, whereas mirtazapine and venlafaxine are second-line treatment options. Tricyclic antidepressants appear to be useful for prevention. Tricyclic antidepressants have been found to be more effective than SSRIs but have greater side effects. Evidence is poor for the use of SSRIs, propranolol, and muscle relaxants for prevention of tension headaches.
Treatment
Treatment for a current tension headache is to drink water and confirm that there is no dehydration. If symptoms do not resolve within an hour for a person who has had water, then stress reduction might resolve the issue.
Exercise
Evidence supports simple neck and shoulder exercises in managing ETTH and CTTH for headaches associated with neck pain. Exercises include stretching, strengthening and range of motion exercises. CTTH can also benefit from combined therapy from stress therapy, exercises and postural correction.
Medications
Episodic
Over-the-counter drugs, like paracetamol, or NSAIDs (ibuprofen, aspirin, naproxen, ketoprofen), can be effective but tend to only be helpful as a treatment for a few times in a week at most. For those with gastrointestinal problems (ulcers and bleeding), and/or kidney problems, acetaminophen is the better choice over aspirin, though both provide roughly equivalent pain relief. It is important to note that large daily doses of paracetamol should be avoided as it may cause liver damage especially in those that consume 3 or more drinks/day and those with pre-existing liver disease. Ibuprofen, one of the NSAIDs listed above, is a common choice for pain relief but may also lead to gastrointestinal discomfort. | Tension headache | Wikipedia | 479 | 322197 | https://en.wikipedia.org/wiki/Tension%20headache | Biology and health sciences | Specific diseases | Health |
Analgesic/caffeine combinations are popular such as the aspirin-caffeine combination or the aspirin, paracetamol and caffeine combinations. Frequent use (daily or skipping just one day in between use for 7–10 days) of any of the above analgesics may, however, lead to medication overuse headache.
Analgesic/sedative combinations are widely used (e.g., analgesic/antihistamine combinations, analgesic/barbiturate combinations such as Fiorinal).
Muscle relaxants are typically used for and are helpful with acute post-traumatic TTH rather than ETTH. Opioid medications are not utilized to treat ETTH. Botulinum toxin does not appear to be helpful.
Chronic
Classes of medications involved in treatment of CTTH include tricyclic antidepressants (TCAs), SSRIs, benzodiazepine (Clonazepam in small evening dose), and muscle relaxants. The most commonly utilized TCA is amitriptyline due to the postulated role in decreasing central sensitization and analgesic relief. Another popular TCA used is Doxepine. SSRIs may also be utilized for management of CTTH. For patients with concurrent muscle spasm and CTTH, the muscle relaxant Tizanidine can be a helpful option.
These medications however, are not effective if concurrent overuse of over the counter medications or other analgesics is occurring. Stopping overuse must occur prior to proceeding with other forms of treatment.
Manual therapy
Current evidence for acupuncture is slight. A 2016 systematic review suggests better evidence among those with frequent tension headaches, but concludes that further trials comparing acupuncture with other treatment options are needed. | Tension headache | Wikipedia | 370 | 322197 | https://en.wikipedia.org/wiki/Tension%20headache | Biology and health sciences | Specific diseases | Health |
People with tension-type headache often use spinal manipulation, soft tissue therapy, and myofascial trigger point treatment. Studies of effectiveness are mixed. A 2006 systematic review found no rigorous evidence supporting manual therapies for tension headache. A 2005 structured review found only weak evidence for the effectiveness of chiropractic manipulation for tension headache, and that it was probably more effective for tension headache than for migraine. Two other systematic reviews published between 2000 and May 2005 did not find conclusive evidence in favor of spinal manipulation. A 2012 systematic review of manual therapy found that hands-on work may reduce both the frequency and the intensity of chronic tension-type headaches. More current literature also appears to be mixed however, CTTH patients may benefit from massage and physiotherapy as suggested by a systemic review examining these modalities via RCTs specifically for this patient population Despite being helpful, the review also makes a point to note that there is no difference in effectiveness long term (6 months) between those CTTH patients utilizing TCAs and physiotherapy. Another systemic review comparing manual therapy to pharmacologic therapy also supports little long term difference in outcome regarding TTH frequency, duration, and intensity.
Epidemiology
As of 2016 tension headaches affect about 1.89 billion people and are more common in women than men (23% to 18% respectively). Despite its benign character, tension-type headache, especially in its chronic form, can impart significant disability on patients as well as burden on society at large. | Tension headache | Wikipedia | 314 | 322197 | https://en.wikipedia.org/wiki/Tension%20headache | Biology and health sciences | Specific diseases | Health |
The European hare (Lepus europaeus), also known as the brown hare, is a species of hare native to Europe and parts of Asia. It is among the largest hare species and is adapted to temperate, open country. Hares are herbivorous and feed mainly on grasses and herbs, supplementing these with twigs, buds, bark and field crops, particularly in winter. Their natural predators include large birds of prey, canids and felids. They rely on high-speed endurance running to escape predation, having long, powerful limbs and large nostrils.
Generally nocturnal and shy in nature, hares change their behaviour in the spring, when they can be seen in broad daylight chasing one another around in fields. During this spring frenzy, they sometimes strike one another with their paws ("boxing"). This is not just competition between males, but also a female hitting a male, either to show she is not yet ready to mate or to test his determination. The female nests in a depression on the surface of the ground rather than in a burrow and the young are active as soon as they are born. Litters may consist of three or four young and a female can bear three litters a year, with hares living for up to twelve years. The breeding season lasts from January to August.
The European hare is listed as being of least concern by the International Union for Conservation of Nature because it has a wide range and is moderately abundant. However, populations have been declining in mainland Europe since the 1960s, at least partly due to changes in farming practices. The hare has been hunted across Europe for centuries, with more than five million being shot each year; in Britain, it has traditionally been hunted by beagling and hare coursing, but these field sports are now illegal. The hare has been a traditional symbol of fertility and reproduction in some cultures and its courtship behaviour in the spring inspired the English idiom mad as a March hare.
Taxonomy and genetics | European hare | Wikipedia | 398 | 322239 | https://en.wikipedia.org/wiki/European%20hare | Biology and health sciences | Lagomorphs | Animals |
The European hare was first described in 1778 by German zoologist Peter Simon Pallas. It shares the genus Lepus (Latin for "hare") with 32 other hare and jackrabbit species, jackrabbits being the name given to some species of hare native to North America. They are distinguished from other leporids (hares and rabbits) by their longer legs and wider nostrils. The Corsican hare, broom hare and Granada hare were at one time considered to be subspecies of the European hare, but DNA sequencing and morphological analysis support their status as separate species.
There is some debate as to whether the European hare and the Cape hare are the same species. A 2005 nuclear gene pool study suggested that they are, but a 2006 study of the mitochondrial DNA of these same animals concluded that they had diverged sufficiently widely to be considered separate species. A 2008 study claims that in the case of Lepus species, with their rapid evolution, species designation cannot be based solely on mtDNA but should also include an examination of the nuclear gene pool. It is possible that the genetic differences between the European and Cape hare are due to geographic separation rather than actual divergence. It has been speculated that in the Near East, hare populations are intergrading and experiencing gene flow. Another 2008 study suggests that more research is needed before a conclusion is reached as to whether a species complex exists; the European hare remains classified as a single species until further data contradicts this assumption.
Cladogenetic analysis suggests that European hares survived the last glacial period during the Pleistocene via refugia in southern Europe (Italian peninsula and Balkans) and Asia Minor. Subsequent colonisations of Central Europe appear to have been initiated by human-caused environmental changes. Genetic diversity in current populations is high with no signs of inbreeding. Gene flow appears to be biased towards males, but overall populations are matrilineally structured. There appears to be a particularly large degree of genetic diversity in hares in the North Rhine-Westphalia region of Germany. It is however possible that restricted gene flow could reduce genetic diversity within populations that become isolated.
Historically, up to 30 subspecies of European hare have been described, although their status has been disputed. These subspecies have been distinguished by differences in pelage colouration, body size, external body measurements, skull morphology and tooth shape.
Sixteen subspecies are listed in the IUCN red book, following Hoffmann and Smith (2005): | European hare | Wikipedia | 490 | 322239 | https://en.wikipedia.org/wiki/European%20hare | Biology and health sciences | Lagomorphs | Animals |
Twenty-nine subspecies of "very variable status" are listed by Chapman and Flux in their book on lagomorphs, including the subspecies above (with the exceptions of L. e. connori, L. e. creticus, L. e. cyprius, L. e. judeae, L. e. rhodius, and L. e. syriacus) and additionally:
Description
The European hare, like other members of the family Leporidae, is a fast-running terrestrial mammal; it has eyes set high on the sides of its head, long ears and a flexible neck. Its teeth grow continuously, the first incisors being modified for gnawing while the second incisors are peg-like and non-functional. There is a gap (diastema) between the incisors and the cheek teeth, the latter being adapted for grinding coarse plant material. The dental formula is 2/1, 0/0, 3/2, 3/3. The dark limb musculature of hares is adapted for high-speed endurance running in open country. By contrast, cottontail rabbits are built for short bursts of speed in more vegetated habitats. Other adaptions for high speed running in hares include wider nostrils and larger hearts. In comparison to the European rabbit, the hare has a proportionally smaller stomach and caecum.
This hare is one of the largest of the lagomorphs. Its head and body length can range from with a tail length of . The body mass is typically between . The hare's elongated ears range from from the notch to tip. It also has long hind feet that have a length of between . The skull has nasal bones that are short, but broad and heavy. The supraorbital ridge has well-developed anterior and posterior lobes and the lacrimal bone projects prominently from the anterior wall of the orbit.
The fur colour is grizzled yellow-brown on the back; rufous on the shoulders, legs, neck and throat; white on the underside and black on the tail and ear tips. The fur on the back is typically longer and more curled than on the rest of the body. The European hare's fur does not turn completely white in the winter as is the case with some other members of the genus, although the sides of the head and base of the ears do develop white areas and the hip and rump region may gain some grey.
Distribution and habitat | European hare | Wikipedia | 510 | 322239 | https://en.wikipedia.org/wiki/European%20hare | Biology and health sciences | Lagomorphs | Animals |
The European hare is native to much of continental Europe and part of Asia. Its range extends from northern Spain to southern Scandinavia, eastern Europe, and northern parts of Western and Central Asia. It has been extending its range into Siberia. It may have been introduced to Great Britain by the Romans about 2000 years ago, based on a lack of archaeological evidence before that, although new radiocarbon dates suggest that it was introduced earlier, between 500-300BCE. It is not present in Ireland, where the mountain hare is the only native hare species. Undocumented introductions probably occurred in some Mediterranean Islands. It has also been introduced, mostly as game animal, to North America in Ontario and New York State, and unsuccessfully in Pennsylvania, Massachusetts, and Connecticut, the Southern Cone in Brazil, Argentina, Uruguay, Paraguay, Bolivia, Chile, Peru and the Falkland Islands, Australia, both islands of New Zealand and the south Pacific coast of Russia.
The European hare primarily lives in open fields with scattered brush for shelter. It is very adaptable and thrives in mixed farmland. According to a study in the Czech Republic, the mean hare densities were highest at elevations below , 40 to 60 days of annual snow cover, of annual precipitation, and a mean annual air temperature of around . With regards to climate, the European hare density was highest in "warm and dry districts with mild winters". In Poland, the European hare is most abundant in areas with few forest edges, perhaps because foxes can use these for cover. It requires cover, such as hedges, ditches and permanent cover areas, because these habitats supply the varied diet it requires, and are found at lower densities in large open fields. Intensive cultivation of the land results in greater mortality of young hares.
In Great Britain, the European hare is seen most frequently on arable farms, especially those with crop rotation and fallow land, wheat and sugar beet crops. In mainly grass farms, its numbers increased with are improved pastures, some arable crops and patches of woodland. It is seen less frequently where foxes are abundant or where there are many common buzzards. It also seems to be fewer in number in areas with high European rabbit populations, although there appears to be little interaction between the two species and no aggression. Although European hares are shot as game when plentiful, this is a self-limiting activity and is less likely to occur in localities where the species is scarce.
Behaviour and life history | European hare | Wikipedia | 496 | 322239 | https://en.wikipedia.org/wiki/European%20hare | Biology and health sciences | Lagomorphs | Animals |
The European hare is primarily nocturnal and spends a third of its time foraging. During daytime, it hides in a depression in the ground called a "form" where it is partially hidden. It can run at , and when confronted by predators it relies on outrunning them in the open. It is generally thought of as asocial but can be seen in both large and small groups. It does not appear to be territorial, living in shared home ranges of around . It communicates with each other by a variety of visual signals. To show interest it raises its ears, while lowering the ears warns others to keep away. When challenging a conspecific, a hare thumps its front feet; the hind feet are used to warn others of a predator. It squeals when hurt or scared, and a female makes "guttural" calls to attract her young. It can live for as long as twelve years.
Food and foraging
The European hare is primarily herbivorous and forages for wild grasses and weeds. With the intensification of agriculture, it has taken to feeding on crops when preferred foods are not available. During the spring and summer, it feeds on soy, clover and corn poppy as well as grasses and herbs. During autumn and winter, it primarily chooses winter wheat, and is also attracted to piles of sugar beet and carrots provided by hunters. It also eats twigs, buds and the bark of shrubs and young fruit trees during winter. It avoids cereal crops when other more attractive foods are available, and appears to prefer high energy foodstuffs over crude dietary fiber. When eating twigs, it strips off the bark to access the vascular tissues which store soluble carbohydrates. Compared to the European rabbit, food passes through the gut more rapidly in the European hare, although digestion rates are similar. It is sometimes coprophagial eating its own green, faecal pellets to recover undigested proteins and vitamins. Two to three adult hares can eat more food than a single sheep. | European hare | Wikipedia | 414 | 322239 | https://en.wikipedia.org/wiki/European%20hare | Biology and health sciences | Lagomorphs | Animals |
European hares forage in groups. Group feeding is beneficial as individuals can spend more time feeding knowing that other hares are being vigilant. Nevertheless, the distribution of food affects these benefits. When food is well-spaced, all hares are able to access it. When food is clumped together, only dominant hares can access it. In small gatherings, dominants are more successful in defending food, but as more individuals join in, they must spend more time driving off others. The larger the group, the less time dominant individuals have in which to eat. Meanwhile, the subordinates can access the food while the dominants are distracted. As such, when in groups, all individuals fare worse when food is clumped as opposed to when it is widely spaced.
Mating and reproduction
European hares have a prolonged breeding season which lasts from January to August. Females, or does, can be found pregnant in all breeding months and males, or bucks, are fertile all year round except during October and November. After this hiatus, the size and activity of the males' testes increase, signalling the start of a new reproductive cycle. This continues through December, January and February when the reproductive tract gains back its functionality. Matings start before ovulation occurs and the first pregnancies of the year often result in a single foetus, with pregnancy failures being common. Peak reproductive activity occurs in March and April, when all females may be pregnant, the majority with three or more foetuses. | European hare | Wikipedia | 306 | 322239 | https://en.wikipedia.org/wiki/European%20hare | Biology and health sciences | Lagomorphs | Animals |
The mating system of the hare has been described as both polygynous (single males mating with multiple females) and promiscuous. Females have six-weekly reproductive cycles and are receptive for only a few hours at a time, making competition among local bucks intense. At the height of the breeding season, this phenomenon is known as "March madness", when the normally nocturnal bucks are forced to be active in the daytime. In addition to dominant animals subduing subordinates, the female fights off her numerous suitors if she is not ready to mate. Fights can be vicious and can leave numerous scars on the ears. In these encounters, hares stand upright and attack each other with their paws, a practice known as "boxing", and this activity is often between a female and a male and not purely between competing males as was previously believed. When a doe is ready to mate, she runs across the countryside, starting a chase that tests the stamina of the following males. When only the fittest male remains, the female stops and allows him to copulate. Female fertility continues through May, June and July, but testosterone production decreases in males and sexual behaviour becomes less overt. Litter sizes decrease as the breeding season draws to a close with no pregnancies occurring after August. The testes of males begin to regress and sperm production ends in September.
Does give birth in hollow depressions in the ground. An individual female may have three litters in a year with a 41- to 42-day gestation period. The young have an average weight of around at birth. The leverets are fully furred and are precocial, being ready to leave the nest soon after they are born, an adaptation to the lack of physical protection relative to that afforded by a burrow. Leverets disperse during the day and come together in the evening close to where they were born. Their mother visits them for nursing soon after sunset; the young suckle for around five minutes, urinating while they do so, with the doe licking up the fluid. She then leaps away so as not to leave an olfactory trail, and the leverets disperse once more. Young can eat solid food after two weeks and are weaned when they are four weeks old. While young of either sex commonly explore their surroundings, natal dispersal tends to be greater in males. Sexual maturity occurs at seven or eight months for females and six months for males.
Health and mortality | European hare | Wikipedia | 498 | 322239 | https://en.wikipedia.org/wiki/European%20hare | Biology and health sciences | Lagomorphs | Animals |
European hares are large leporids and adults can only be tackled by large predators such as canids, felids and the largest birds of prey. In Poland it was found that the consumption of hares by foxes was at its highest during spring, when the availability of small animal prey was low; at this time of year, hares may constitute up to 50% of the biomass eaten by foxes, with 50% of the mortality of adult hares being caused by their predation. In Scandinavia, a natural epizootic of sarcoptic mange which reduced the population of red foxes dramatically, resulted in an increase in the number of European hares, which returned to previous levels when the numbers of foxes subsequently increased. The golden eagle preys on the European hare in the Alps, the Carpathians, the Apennines and northern Spain. In North America, foxes and coyotes are probably the most common predators, with bobcats and lynx also preying on them in more remote locations.
European hares have both external and internal parasites. One study found that 54% of animals in Slovakia were parasitised by nematodes and over 90% by coccidia. In Australia, European hares were reported as being infected by four species of nematode, six of coccidian, several liver flukes and two canine tapeworms. They were also found to host rabbit fleas (Spilopsyllus cuniculi), stickfast fleas (Echidnophaga myrmecobii), lice (Haemodipsus setoni and H. lyriocephalus), and mites (Leporacarus gibbus).
European brown hare syndrome (EBHS) is a disease caused by a calicivirus similar to that causing rabbit haemorrhagic disease (RHD) and can similarly be fatal, but cross infection between the two mammal species does not occur. Other threats to the hare are pasteurellosis, yersiniosis (pseudo-tuberculosis), coccidiosis and tularaemia, which are the principal sources of mortality.
In October 2018, it was reported that a mutated form of the rabbit haemorrhagic disease virus (RHDV2) may have jumped to hares in the UK. Normally rare in hares, a significant die-off from the virus has also occurred in Spain.
Relationship with humans | European hare | Wikipedia | 499 | 322239 | https://en.wikipedia.org/wiki/European%20hare | Biology and health sciences | Lagomorphs | Animals |
In folklore, literature, and art
In Europe, the hare has been a symbol of sex and fertility since at least Ancient Greece. The Greeks associated it with the gods Dionysus, Aphrodite and Artemis as well as with satyrs and cupids. The Christian Church connected the hare with lustfulness and homosexuality, but also associated it with the persecution of the church because of the way it was commonly hunted.
In Northern Europe, Easter imagery often involves hares or rabbits. Citing folk Easter customs in Leicestershire, England, where "the profits of the land called Harecrop Leys were applied to providing a meal which was thrown on the ground at the 'Hare-pie Bank'", the 19th-century scholar Charles Isaac Elton proposed a possible connection between these customs and the worship of Ēostre. In his 19th-century study of the hare in folk custom and mythology, Charles J. Billson cites folk customs involving the hare around Easter in Northern Europe, and argues that the hare was probably a sacred animal in prehistoric Britain's festival of springtime. Observation of the hare's springtime mating behaviour led to the popular English idiom "mad as a March hare", with similar phrases from the sixteenth century writings of John Skelton and Sir Thomas More onwards. The mad hare reappears in Alice's Adventures in Wonderland by Lewis Carroll, in which Alice participates in a crazy tea-party with the March Hare and the Hatter.
Any connection of the hare to Ēostre is doubtful. John Andrew Boyle cites an etymology dictionary by Alfred Ernout and Antoine Meillet, who wrote that the lights of Ēostre were carried by hares, that Ēostre represented spring fecundity, love and sexual pleasure. Boyle responds that almost nothing is known about Ēostre, and that the authors had seemingly accepted the identification of Ēostre with the Norse goddess Freyja, but that the hare is not associated with Freyja either. Boyle adds that "when the authors speak of the hare as the 'companion of Aphrodite and of satyrs and cupids' and 'in the Middle Ages [the hare] appears beside the figure of [mythological] Luxuria', they are on much surer ground." | European hare | Wikipedia | 459 | 322239 | https://en.wikipedia.org/wiki/European%20hare | Biology and health sciences | Lagomorphs | Animals |
The hare is a character in some fables, such as The Tortoise and the Hare of Aesop. The story was annexed to a philosophical problem by Zeno of Elea, who created a set of paradoxes to support Parmenides' attack on the idea of continuous motion, as each time the hare (or the hero Achilles) moves to where the tortoise was, the tortoise moves just a little further away. The German Renaissance artist Albrecht Dürer realistically depicted a hare in his 1502 watercolour painting Young Hare.
Food and hunting
Across Europe, over five million European hares are shot each year, making it probably the most important game mammal on the continent. This popularity has threatened regional varieties such as those of France and Denmark, through large-scale importing of hares from Eastern European countries such as Hungary. Hares have traditionally been hunted in Britain by beagling and hare coursing. In beagling, the hare is hunted with a pack of small hunting dogs, beagles, followed by the human hunters on foot. In Britain, the 2004 Hunting Act banned hunting of hares with dogs, so the 60 beagle packs now use artificial "trails", or may legally continue to hunt rabbits. Hare coursing with greyhounds was once an aristocratic pursuit, forbidden to lower social classes. More recently, informal hare coursing became a lower class activity and was conducted without the landowner's permission; it is also now illegal. In Scotland concerns have been raised over the increasing numbers of hares shot under license.
Hare is traditionally cooked by jugging: a whole hare is cut into pieces, marinated and cooked slowly with red wine and juniper berries in a tall jug that stands in a pan of water. It is traditionally served with (or briefly cooked with) the hare's blood and port wine. Hare can also be cooked in a casserole. The meat is darker and more strongly flavoured than that of rabbits. Young hares can be roasted; the meat of older hares becomes too tough for roasting, and may be slow-cooked.
Status | European hare | Wikipedia | 430 | 322239 | https://en.wikipedia.org/wiki/European%20hare | Biology and health sciences | Lagomorphs | Animals |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.