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In Europe, there are two varieties of chrain. "Red" chrain is mixed with red beetroot and "white" chrain contains no beetroot. Chrain is a part of Christian Easter and Jewish Passover tradition (as maror) in Eastern and Central Europe. In the Christian tradition, horseradish is eaten during Eastertide (Paschaltide) as ... | Horseradish | Wikipedia | 482 | 45714 | https://en.wikipedia.org/wiki/Horseradish | Biology and health sciences | Brassicales | null | vital_articles |
Relation to wasabi
Outside Japan, the Japanese condiment wasabi, although traditionally prepared from the true wasabi plant (Wasabia japonica), is now usually made with horseradish due to the scarcity of the wasabi plant. The Japanese botanical name for horseradish is , or "Western wasabi". Both plants are members of t... | Horseradish | Wikipedia | 243 | 45714 | https://en.wikipedia.org/wiki/Horseradish | Biology and health sciences | Brassicales | null | vital_articles |
The Arecaceae () is a family of perennial, flowering plants in the monocot order Arecales. Their growth form can be climbers, shrubs, tree-like and stemless plants, all commonly known as palms. Those having a tree-like form are colloquially called palm trees. Currently, 181 genera with around 2,600 species are known, m... | Arecaceae | Wikipedia | 371 | 45715 | https://en.wikipedia.org/wiki/Arecaceae | Biology and health sciences | Monocots | null | vital_articles |
Morphology
Whether as shrubs, tree-like, or vines, palms have two methods of growth: solitary or clustered. The common representation is that of a solitary shoot ending in a crown of leaves. This monopodial character may be exhibited by prostrate, trunkless, and trunk-forming members. Some common palms restricted to so... | Arecaceae | Wikipedia | 505 | 45715 | https://en.wikipedia.org/wiki/Arecaceae | Biology and health sciences | Monocots | null | vital_articles |
The Arecaceae are notable among monocots for their height and for the size of their seeds, leaves, and inflorescences. Ceroxylon quindiuense, Colombia's national "tree", is the tallest monocot in the world, reaching up to tall. The coco de mer (Lodoicea maldivica) has the largest seeds of any plant, in diameter and w... | Arecaceae | Wikipedia | 415 | 45715 | https://en.wikipedia.org/wiki/Arecaceae | Biology and health sciences | Monocots | null | vital_articles |
Palms inhabit a variety of ecosystems. More than two-thirds of palm species live in humid moist forests, where some species grow tall enough to form part of the canopy and shorter ones form part of the understory. Some species form pure stands in areas with poor drainage or regular flooding, including Raphia hookeri wh... | Arecaceae | Wikipedia | 488 | 45715 | https://en.wikipedia.org/wiki/Arecaceae | Biology and health sciences | Monocots | null | vital_articles |
The is the sixth subfamily of Arecaceae in N.W. Uhl and J. Dransfield's 1987 classification. Members of this group have distinct monopodial flower clusters. Other distinct features include a gynoecium with five to 10 joined carpels, and flowers with more than three parts per whorl. Fruits are multiple-seeded and have ... | Arecaceae | Wikipedia | 435 | 45715 | https://en.wikipedia.org/wiki/Arecaceae | Biology and health sciences | Monocots | null | vital_articles |
Archontophoenix—Bangalow palm
Areca—Betel palm
Astrocaryum
Attalea
Bactris—Pupunha
Beccariophoenix—Beccariophoenix alfredii
Bismarckia—Bismarck palm
Borassus—Palmyra palm, sugar palm, toddy palm
Butia
Calamus—Rattan palm
Ceroxylon
Cocos—Coconut
Coccothrinax
Copernicia—Carnauba wax palm
Corypha—Gebang palm, Buri palm or... | Arecaceae | Wikipedia | 497 | 45715 | https://en.wikipedia.org/wiki/Arecaceae | Biology and health sciences | Monocots | null | vital_articles |
Evidence for cultivation of the date palm by Mesopotamians and other Middle Eastern peoples exists from more than 5,000 years ago, in the form of date wood, pits for storing dates, and other remains of the date palm in Mesopotamian sites. The date palm had a significant effect on the history of the Middle East and Nort... | Arecaceae | Wikipedia | 277 | 45715 | https://en.wikipedia.org/wiki/Arecaceae | Biology and health sciences | Monocots | null | vital_articles |
Along with dates mentioned above, members of the palm family with human uses are numerous:
The type member of Arecaceae is the areca palm (Areca catechu), the fruit of which, the areca nut, is chewed with the betel leaf for intoxicating effects.
Carnauba wax is harvested from the leaves of South American palms of the g... | Arecaceae | Wikipedia | 457 | 45715 | https://en.wikipedia.org/wiki/Arecaceae | Biology and health sciences | Monocots | null | vital_articles |
Ornamental uses: Today, palms are valuable as ornamental plants and are often grown along streets in tropical and subtropical cities. Chamaedorea elegans is a popular houseplant and is grown indoors for its low maintenance. Farther north, palms are a common feature in botanical gardens or as indoor plants. Few palms to... | Arecaceae | Wikipedia | 328 | 45715 | https://en.wikipedia.org/wiki/Arecaceae | Biology and health sciences | Monocots | null | vital_articles |
Endangered species
Like many other plants, palms have been threatened by human intervention and exploitation. The greatest risk to palms is destruction of habitat, especially in the tropical forests, due to urbanization, wood-chipping, mining, and conversion to farmland. Palms rarely reproduce after such great changes... | Arecaceae | Wikipedia | 488 | 45715 | https://en.wikipedia.org/wiki/Arecaceae | Biology and health sciences | Monocots | null | vital_articles |
Raoiella indica, the red palm mite
Caryobruchus gleditsiae, the palm seed beetle or palm seed weevil
Rhynchophorus ferrugineus, the red palm weevil, recently introduced to Europe
Symbolism
The palm branch was a symbol of triumph and victory in classical antiquity. The Romans rewarded champions of the games and cele... | Arecaceae | Wikipedia | 334 | 45715 | https://en.wikipedia.org/wiki/Arecaceae | Biology and health sciences | Monocots | null | vital_articles |
Ailanthus altissima (Ghetto palm), a tree in the flowering plant family Simaroubaceae
Alocasia odora x gageana 'Calidora' (Persian palm), a flowering plant in the family Araceae
Aloe thraskii (Palm aloe), a flowering plant in the family Asphodelaceae
Amorphophallus konjac (Snake palm), a flowering plant in the family A... | Arecaceae | Wikipedia | 503 | 45715 | https://en.wikipedia.org/wiki/Arecaceae | Biology and health sciences | Monocots | null | vital_articles |
Musa species (Banana palm), a flowering plant in the family Musaceae
Pachypodium lamerei (Madagascar palm), a flowering plant in the family Apocynaceae
Pandanus spiralis (Screw palm), a flowering plant in the family Pandanaceae and perhaps other Pandanus spp.
Ravenala (Traveller's palm), a flowering plant in the family... | Arecaceae | Wikipedia | 193 | 45715 | https://en.wikipedia.org/wiki/Arecaceae | Biology and health sciences | Monocots | null | vital_articles |
Panthera is a genus within the family Felidae, and one of two extant genera in the subfamily Pantherinae. It contains the largest living members of the cat family. There are five living species: the jaguar, leopard, lion, snow leopard and tiger. Numerous extinct species are also named, including the cave lion and Ameri... | Panthera | Wikipedia | 304 | 45729 | https://en.wikipedia.org/wiki/Panthera | Biology and health sciences | Felines | Animals | vital_articles |
Evolution
The geographic origin of the genus Panthera is uncertain, though the earliest known definitive species Panthera principialis is from Tanzania. P. blytheae from northern Central Asia, originally described as the oldest known Panthera species, is suggested to be similar in skull features to the snow leopard, bu... | Panthera | Wikipedia | 359 | 45729 | https://en.wikipedia.org/wiki/Panthera | Biology and health sciences | Felines | Animals | vital_articles |
Classification
Panthera was named and described by Lorenz Oken in 1816 who placed all the spotted cats in this group. During the 19th and 20th centuries, various explorers and staff of natural history museums suggested numerous subspecies, or at times called "races", for all Panthera species. The taxonomist Reginald I... | Panthera | Wikipedia | 512 | 45729 | https://en.wikipedia.org/wiki/Panthera | Biology and health sciences | Felines | Animals | vital_articles |
The mineral pyrite ( ), or iron pyrite, also known as fool's gold, is an iron sulfide with the chemical formula FeS2 (iron (II) disulfide). Pyrite is the most abundant sulfide mineral.
Pyrite's metallic luster and pale brass-yellow hue give it a superficial resemblance to gold, hence the well-known nickname of fool's ... | Pyrite | Wikipedia | 456 | 45756 | https://en.wikipedia.org/wiki/Pyrite | Physical sciences | Minerals | Earth science | vital_articles |
Pyrite has been used since classical times to manufacture copperas (ferrous sulfate). Iron pyrite was heaped up and allowed to weather (an example of an early form of heap leaching). The acidic runoff from the heap was then boiled with iron to produce iron sulfate. In the 15th century, new methods of such leaching bega... | Pyrite | Wikipedia | 437 | 45756 | https://en.wikipedia.org/wiki/Pyrite | Physical sciences | Minerals | Earth science | vital_articles |
Pyrite is used to make marcasite jewelry. Marcasite jewelry, using small faceted pieces of pyrite, often set in silver, has been made since ancient times and was popular in the Victorian era. At the time when the term became common in jewelry making, "marcasite" referred to all iron sulfides including pyrite, and not t... | Pyrite | Wikipedia | 485 | 45756 | https://en.wikipedia.org/wiki/Pyrite | Physical sciences | Minerals | Earth science | vital_articles |
From the perspective of classical inorganic chemistry, which assigns formal oxidation states to each atom, pyrite and marcasite are probably best described as Fe2+[S2]2−. This formalism recognizes that the sulfur atoms in pyrite occur in pairs with clear S–S bonds. These persulfide [–S–S–] units can be viewed as derive... | Pyrite | Wikipedia | 507 | 45756 | https://en.wikipedia.org/wiki/Pyrite | Physical sciences | Minerals | Earth science | vital_articles |
The sulfur centers occur in pairs, described as S22−. Reduction of pyrite with potassium gives potassium dithioferrate, KFeS2. This material features ferric ions and isolated sulfide (S2-) centers.
The S atoms are tetrahedral, being bonded to three Fe centers and one other S atom. The site symmetry at Fe and S positio... | Pyrite | Wikipedia | 508 | 45756 | https://en.wikipedia.org/wiki/Pyrite | Physical sciences | Minerals | Earth science | vital_articles |
Distinguishing similar minerals
Pyrite is distinguishable from native gold by its hardness, brittleness and crystal form. Pyrite fractures are very uneven, sometimes conchoidal because it does not cleave along a preferential plane. Native gold nuggets, or glitters, do not break but deform in a ductile way. Pyrite is br... | Pyrite | Wikipedia | 492 | 45756 | https://en.wikipedia.org/wiki/Pyrite | Physical sciences | Minerals | Earth science | vital_articles |
2FeS2{\scriptstyle (s)} + 7O2{\scriptstyle (g)} + 2H2O{\scriptstyle (l)} -> 2Fe^{2+}{\scriptstyle (aq)} + 4SO4^{2-}{\scriptstyle (aq)} + 4H+{\scriptstyle (aq)}.
Dust explosions
Pyrite oxidation is sufficiently exothermic that underground coal mines in high-sulfur coal seams have occasionally had serious problems with ... | Pyrite | Wikipedia | 504 | 45756 | https://en.wikipedia.org/wiki/Pyrite | Physical sciences | Minerals | Earth science | vital_articles |
Occurrence
Pyrite is the most common of sulfide minerals and is widespread in igneous, metamorphic, and sedimentary rocks. It is a common accessory mineral in igneous rocks, where it also occasionally occurs as larger masses arising from an immiscible sulfide phase in the original magma. It is found in metamorphic rock... | Pyrite | Wikipedia | 315 | 45756 | https://en.wikipedia.org/wiki/Pyrite | Physical sciences | Minerals | Earth science | vital_articles |
Biomimetics or biomimicry is the emulation of the models, systems, and elements of nature for the purpose of solving complex human problems. The terms "biomimetics" and "biomimicry" are derived from (bios), life, and μίμησις (mīmēsis), imitation, from μιμεῖσθαι (mīmeisthai), to imitate, from μῖμος (mimos), actor. A cl... | Biomimetics | Wikipedia | 445 | 45784 | https://en.wikipedia.org/wiki/Biomimetics | Technology | Biotechnology | null | vital_articles |
During the 1950s the American biophysicist and polymath Otto Schmitt developed the concept of "biomimetics". During his doctoral research he developed the Schmitt trigger by studying the nerves in squid, attempting to engineer a device that replicated the biological system of nerve propagation. He continued to focus on... | Biomimetics | Wikipedia | 464 | 45784 | https://en.wikipedia.org/wiki/Biomimetics | Technology | Biotechnology | null | vital_articles |
One of the latest examples of biomimicry has been created by Johannes-Paul Fladerer and Ernst Kurzmann by the description of "managemANT". This term (a combination of the words "management" and "ant"), describes the usage of behavioural strategies of ants in economic and management strategies. The potential long-term i... | Biomimetics | Wikipedia | 411 | 45784 | https://en.wikipedia.org/wiki/Biomimetics | Technology | Biotechnology | null | vital_articles |
BFRs take inspiration from flying mammals, birds, or insects. BFRs can have flapping wings, which generate the lift and thrust, or they can be propeller actuated. BFRs with flapping wings have increased stroke efficiencies, increased maneuverability, and reduced energy consumption in comparison to propeller actuated BF... | Biomimetics | Wikipedia | 440 | 45784 | https://en.wikipedia.org/wiki/Biomimetics | Technology | Biotechnology | null | vital_articles |
Insect inspired BFRs typically take inspiration from beetles or dragonflies. An example of a beetle inspired BFR is the prototype by Phan and Park, and a dragonfly inspired BFR is the prototype by Hu et al. The flapping frequency of insect inspired BFRs are much higher than those of other BFRs; this is because of the a... | Biomimetics | Wikipedia | 507 | 45784 | https://en.wikipedia.org/wiki/Biomimetics | Technology | Biotechnology | null | vital_articles |
Biomorphic architecture, also referred to as bio-decoration, on the other hand, refers to the use of formal and geometric elements found in nature, as a source of inspiration for aesthetic properties in designed architecture, and may not necessarily have non-physical, or economic functions. A historic example of biomor... | Biomimetics | Wikipedia | 471 | 45784 | https://en.wikipedia.org/wiki/Biomimetics | Technology | Biotechnology | null | vital_articles |
A similar inspiration was drawn from the porous walls of termite mounds to design a naturally ventilated façade with a small ventilation gap. This design of façade is able to induce air flow due to the Venturi effect and continuously circulates rising air in the ventilation slot. Significant transfer of heat between th... | Biomimetics | Wikipedia | 472 | 45784 | https://en.wikipedia.org/wiki/Biomimetics | Technology | Biotechnology | null | vital_articles |
Such materials would need to be manufactured into bulk materials with complex shapes at high volume and low cost and would serve a variety of fields such as construction, transportation, energy storage and conversion. In a classic design problem, strength and toughness are more likely to be mutually exclusive, i.e., st... | Biomimetics | Wikipedia | 467 | 45784 | https://en.wikipedia.org/wiki/Biomimetics | Technology | Biotechnology | null | vital_articles |
Freeze casting (ice templating), an inexpensive method to mimic natural layered structures, was employed by researchers at Lawrence Berkeley National Laboratory to create alumina-Al-Si and IT HAP-epoxy layered composites that match the mechanical properties of bone with an equivalent mineral/organic content. Various fu... | Biomimetics | Wikipedia | 394 | 45784 | https://en.wikipedia.org/wiki/Biomimetics | Technology | Biotechnology | null | vital_articles |
Self healing-materials
In some biological systems, self-healing occurs via chemical releases at the site of fracture, which initiate a systemic response to transport repairing agents to the fracture site. This promotes autonomic healing. To demonstrate the use of micro-vascular networks for autonomic healing, research... | Biomimetics | Wikipedia | 420 | 45784 | https://en.wikipedia.org/wiki/Biomimetics | Technology | Biotechnology | null | vital_articles |
Marine mussels can stick easily and efficiently to surfaces underwater under the harsh conditions of the ocean. Mussels use strong filaments to adhere to rocks in the inter-tidal zones of wave-swept beaches, preventing them from being swept away in strong sea currents. Mussel foot proteins attach the filaments to rocks... | Biomimetics | Wikipedia | 420 | 45784 | https://en.wikipedia.org/wiki/Biomimetics | Technology | Biotechnology | null | vital_articles |
Superliquiphobicity emerges when a solid surface possesses minute roughness, forming interfaces with droplets through wetting while altering contact angles. This behavior hinges on the roughness factor (Rf), defining the ratio of solid-liquid area to its projection, influencing contact angles. On rough surfaces, non-we... | Biomimetics | Wikipedia | 456 | 45784 | https://en.wikipedia.org/wiki/Biomimetics | Technology | Biotechnology | null | vital_articles |
Biomimetic materials are gaining increasing attention in the field of optics and photonics. There are still little known bioinspired or biomimetic products involving the photonic properties of plants or animals. However, understanding how nature designed such optical materials from biological resources is a current fie... | Biomimetics | Wikipedia | 298 | 45784 | https://en.wikipedia.org/wiki/Biomimetics | Technology | Biotechnology | null | vital_articles |
Another example of mimicking plants, is the Pollia condensata, also known as the marble berry. The chiral self-assembly of cellulose inspired by the Pollia condensata berry has been exploited to make optically active films. Such films are made from cellulose which is a biodegradable and biobased resource obtained from ... | Biomimetics | Wikipedia | 454 | 45784 | https://en.wikipedia.org/wiki/Biomimetics | Technology | Biotechnology | null | vital_articles |
Structural coloration produces the rainbow colours of soap bubbles, butterfly wings and many beetle scales. Phase-separation has been used to fabricate ultra-white scattering membranes from polymethylmethacrylate, mimicking the beetle Cyphochilus. LED lights can be designed to mimic the patterns of scales on fireflies'... | Biomimetics | Wikipedia | 492 | 45784 | https://en.wikipedia.org/wiki/Biomimetics | Technology | Biotechnology | null | vital_articles |
Technologists like Jas Johl have speculated that the functionality of vacuole cells could be used to design highly adaptable security systems. "The functionality of a vacuole, a biological structure that guards and promotes growth, illuminates the value of adaptability as a guiding principle for security." The function... | Biomimetics | Wikipedia | 330 | 45784 | https://en.wikipedia.org/wiki/Biomimetics | Technology | Biotechnology | null | vital_articles |
Most viruses have an outer capsule 20 to 300 nm in diameter. Virus capsules are remarkably robust and capable of withstanding temperatures as high as 60 °C; they are stable across the pH range 2–10. Viral capsules can be used to create nano device components such as nanowires, nanotubes, and quantum dots. Tubular virus... | Biomimetics | Wikipedia | 343 | 45784 | https://en.wikipedia.org/wiki/Biomimetics | Technology | Biotechnology | null | vital_articles |
The clouded leopard (Neofelis nebulosa), also called mainland clouded leopard, is a wild cat inhabiting dense forests from the foothills of the Himalayas through Northeast India and Bhutan to mainland Southeast Asia into South China. It was first described in 1821 on the basis of a skin of an individual from China. The... | Clouded leopard | Wikipedia | 447 | 45798 | https://en.wikipedia.org/wiki/Clouded%20leopard | Biology and health sciences | Felines | Animals | vital_articles |
Felis diardi proposed by Georges Cuvier in 1823 was based on a clouded leopard skin from Java.
It was considered a clouded leopard subspecies by Reginald Innes Pocock in 1917. In 2006, it was identified as a distinct Neofelis species, the Sunda clouded leopard. Populations in Taiwan and Hainan Island are considered to ... | Clouded leopard | Wikipedia | 492 | 45798 | https://en.wikipedia.org/wiki/Clouded%20leopard | Biology and health sciences | Felines | Animals | vital_articles |
Its hyoid bone is ossified, making it possible to purr. Its pupils contract into vertical slits. Irises are brownish yellow to grayish green. Melanistic clouded leopards are uncommon. It has rather short limbs compared to the other big cats. Its hind limbs are longer than its front limbs to allow for increased jumping ... | Clouded leopard | Wikipedia | 373 | 45798 | https://en.wikipedia.org/wiki/Clouded%20leopard | Biology and health sciences | Felines | Animals | vital_articles |
In India, it occurs in the states of Sikkim, northern West Bengal, Tripura, Mizoram, Manipur, Assam, Nagaland and Arunachal Pradesh, as well as in the Meghalaya subtropical forests. In Pakke Tiger Reserve, a clouded leopard was photographed in semi-evergreen forest at an elevation of . In Sikkim, clouded leopards were ... | Clouded leopard | Wikipedia | 457 | 45798 | https://en.wikipedia.org/wiki/Clouded%20leopard | Biology and health sciences | Felines | Animals | vital_articles |
The last confirmed record of a Formosan clouded leopard dates to 1989, when the skin of a young individual was found in the Taroko National Park. It was not recorded during an extensive camera trapping survey conducted from 1997 to 2012 in more than 1,450 sites inside and outside Taiwanese protected areas.
Behaviour a... | Clouded leopard | Wikipedia | 497 | 45798 | https://en.wikipedia.org/wiki/Clouded%20leopard | Biology and health sciences | Felines | Animals | vital_articles |
Hunting and diet
When hunting, the clouded leopard stalks its prey or waits for the prey to approach. After making and feeding on a kill, it usually retreats into trees to digest and rest. Its prey includes both arboreal and terrestrial vertebrates.
Pocock presumed that it is adapted for preying upon herbivorous mamma... | Clouded leopard | Wikipedia | 467 | 45798 | https://en.wikipedia.org/wiki/Clouded%20leopard | Biology and health sciences | Felines | Animals | vital_articles |
Clouded leopard require larger areas of intact forest than are present in many parts of their range. They are threatened by habitat loss following large–scale deforestation and commercial poaching for the wildlife trade. In Myanmar, 301 body parts of at least 279 clouded leopards, mostly skins and skeletons, were obser... | Clouded leopard | Wikipedia | 495 | 45798 | https://en.wikipedia.org/wiki/Clouded%20leopard | Biology and health sciences | Felines | Animals | vital_articles |
In March 2011, two breeding females at the Nashville Zoo at Grassmere gave birth to three cubs, which were raised by zookeepers. Each cub weighed . In June 2011, two cubs were born at the Point Defiance Zoo & Aquarium. The breeding pair was brought from the Khao Kheow Open Zoo in Thailand in an ongoing education and re... | Clouded leopard | Wikipedia | 142 | 45798 | https://en.wikipedia.org/wiki/Clouded%20leopard | Biology and health sciences | Felines | Animals | vital_articles |
Dijkstra's algorithm ( ) is an algorithm for finding the shortest paths between nodes in a weighted graph, which may represent, for example, a road network. It was conceived by computer scientist Edsger W. Dijkstra in 1956 and published three years later.
Dijkstra's algorithm finds the shortest path from a given sour... | Dijkstra's algorithm | Wikipedia | 458 | 45809 | https://en.wikipedia.org/wiki/Dijkstra%27s%20algorithm | Mathematics | Graph theory | null | vital_articles |
Dijkstra thought about the shortest path problem while working as a programmer at the Mathematical Center in Amsterdam in 1956. He wanted to demonstrate the capabilities of the new ARMAC computer. His objective was to choose a problem and a computer solution that non-computing people could understand. He designed the s... | Dijkstra's algorithm | Wikipedia | 235 | 45809 | https://en.wikipedia.org/wiki/Dijkstra%27s%20algorithm | Mathematics | Graph theory | null | vital_articles |
Create a set of all unvisited nodes: the unvisited set.
Assign to every node a distance from start value: for the starting node, it is zero, and for all other nodes, it is infinity, since initially no path is known to these nodes. During execution, the distance of a node N is the length of the shortest path discovered... | Dijkstra's algorithm | Wikipedia | 499 | 45809 | https://en.wikipedia.org/wiki/Dijkstra%27s%20algorithm | Mathematics | Graph theory | null | vital_articles |
From the current intersection, the distance to every neighbor (directly-connected) intersection is assessed by summing the label (value) of the current intersection and the distance to the neighbor and then relabeling the neighbor with the lesser of that sum and the neighbor's existing label. I.e., the neighbor is rela... | Dijkstra's algorithm | Wikipedia | 505 | 45809 | https://en.wikipedia.org/wiki/Dijkstra%27s%20algorithm | Mathematics | Graph theory | null | vital_articles |
To find the shortest path between vertices and , the search terminates after line 10 if . The shortest path from to can be obtained by reverse iteration:
1 S ← empty sequence
2 u ← target
3 if prev[u] is defined or u = source: // Proceed if the vertex is reachable
4 while u is defined: ... | Dijkstra's algorithm | Wikipedia | 408 | 45809 | https://en.wikipedia.org/wiki/Dijkstra%27s%20algorithm | Mathematics | Graph theory | null | vital_articles |
1 function Dijkstra(Graph, source):
2 create vertex priority queue Q
3
4 dist[source] ← 0 // Initialization
5 Q.add_with_priority(source, 0) // associated priority equals dist[·]
6
7 for each vertex v in Graph.Vertices:
8 if v ≠ source
9 ... | Dijkstra's algorithm | Wikipedia | 507 | 45809 | https://en.wikipedia.org/wiki/Dijkstra%27s%20algorithm | Mathematics | Graph theory | null | vital_articles |
Base case
The base case is when there is just one visited node, . Its distance is defined to be zero, which is the shortest distance, since negative weights are not allowed. Hence, the hypothesis holds.
Induction
Assuming that the hypothesis holds for visited nodes, to show it holds for nodes, let be the next vis... | Dijkstra's algorithm | Wikipedia | 497 | 45809 | https://en.wikipedia.org/wiki/Dijkstra%27s%20algorithm | Mathematics | Graph theory | null | vital_articles |
where and are the complexities of the decrease-key and extract-minimum operations in , respectively.
The simplest version of Dijkstra's algorithm stores the vertex set as a linked list or array, and edges as an adjacency list or matrix. In this case, extract-minimum is simply a linear search through all vertices in... | Dijkstra's algorithm | Wikipedia | 399 | 45809 | https://en.wikipedia.org/wiki/Dijkstra%27s%20algorithm | Mathematics | Graph theory | null | vital_articles |
Moreover, not inserting all nodes in a graph makes it possible to extend the algorithm to find the shortest path from a single source to the closest of a set of target nodes on infinite graphs or those too large to represent in memory. The resulting algorithm is called uniform-cost search (UCS) in the artificial intell... | Dijkstra's algorithm | Wikipedia | 348 | 45809 | https://en.wikipedia.org/wiki/Dijkstra%27s%20algorithm | Mathematics | Graph theory | null | vital_articles |
Optimality for comparison-sorting by distance
As well as simply computing distances and paths, Dijkstra's algorithm can be used to sort vertices by their distances from a given starting vertex.
In 2023, Haeupler, Rozhoň, Tětek, Hladík, and Tarjan (one of the inventors of the 1984 heap), proved that, for this sorting p... | Dijkstra's algorithm | Wikipedia | 448 | 45809 | https://en.wikipedia.org/wiki/Dijkstra%27s%20algorithm | Mathematics | Graph theory | null | vital_articles |
Unlike Dijkstra's algorithm, the Bellman–Ford algorithm can be used on graphs with negative edge weights, as long as the graph contains no negative cycle reachable from the source vertex s. The presence of such cycles means that no shortest path can be found, since the label becomes lower each time the cycle is travers... | Dijkstra's algorithm | Wikipedia | 415 | 45809 | https://en.wikipedia.org/wiki/Dijkstra%27s%20algorithm | Mathematics | Graph theory | null | vital_articles |
Structural engineering is a sub-discipline of civil engineering in which structural engineers are trained to design the 'bones and joints' that create the form and shape of human-made structures. Structural engineers also must understand and calculate the stability, strength, rigidity and earthquake-susceptibility of b... | Structural engineering | Wikipedia | 478 | 45829 | https://en.wikipedia.org/wiki/Structural%20engineering | Technology | Disciplines | null | vital_articles |
No record exists of the first calculations of the strength of structural members or the behavior of structural material, but the profession of a structural engineer only really took shape with the Industrial Revolution and the re-invention of concrete (see History of Concrete). The physical sciences underlying structur... | Structural engineering | Wikipedia | 428 | 45829 | https://en.wikipedia.org/wiki/Structural%20engineering | Technology | Disciplines | null | vital_articles |
The history of structural engineering contains many collapses and failures. Sometimes this is due to obvious negligence, as in the case of the Pétion-Ville school collapse, in which Rev. Fortin Augustin " constructed the building all by himself, saying he didn't need an engineer as he had good knowledge of constructio... | Structural engineering | Wikipedia | 478 | 45829 | https://en.wikipedia.org/wiki/Structural%20engineering | Technology | Disciplines | null | vital_articles |
Structural engineering has existed since humans first started to construct their structures. It became a more defined and formalized profession with the emergence of architecture as a distinct profession from engineering during the industrial revolution in the late 19th century. Until then, the architect and the struct... | Structural engineering | Wikipedia | 400 | 45829 | https://en.wikipedia.org/wiki/Structural%20engineering | Technology | Disciplines | null | vital_articles |
The structural design for a building must ensure that the building can stand up safely, able to function without excessive deflections or movements which may cause fatigue of structural elements, cracking or failure of fixtures, fittings or partitions, or discomfort for occupants. It must account for movements and forc... | Structural engineering | Wikipedia | 504 | 45829 | https://en.wikipedia.org/wiki/Structural%20engineering | Technology | Disciplines | null | vital_articles |
Aerospace structure types include launch vehicles, (Atlas, Delta, Titan), missiles (ALCM, Harpoon), Hypersonic vehicles (Space Shuttle), military aircraft (F-16, F-18) and commercial aircraft (Boeing 777, MD-11). Aerospace structures typically consist of thin plates with stiffeners for the external surfaces, bulkheads,... | Structural engineering | Wikipedia | 509 | 45829 | https://en.wikipedia.org/wiki/Structural%20engineering | Technology | Disciplines | null | vital_articles |
Many of these elements can be classified according to form (straight, plane / curve) and dimensionality (one-dimensional / two-dimensional):
Columns
Columns are elements that carry only axial force (compression) or both axial force and bending (which is technically called a beam-column but practically, just a column)... | Structural engineering | Wikipedia | 395 | 45829 | https://en.wikipedia.org/wiki/Structural%20engineering | Technology | Disciplines | null | vital_articles |
A truss is a structure comprising members and connection points or nodes. When members are connected at nodes and forces are applied at nodes members can act in tension or compression. Members acting in compression are referred to as compression members or struts while members acting in tension are referred to as tensi... | Structural engineering | Wikipedia | 495 | 45829 | https://en.wikipedia.org/wiki/Structural%20engineering | Technology | Disciplines | null | vital_articles |
Common structural materials are:
Iron: wrought iron, cast iron
Concrete: reinforced concrete, prestressed concrete
Alloy: steel, stainless steel
Masonry
Timber: hardwood, softwood
Aluminium
Composite materials: plywood
Other structural materials: adobe, bamboo, carbon fibre, fiber reinforced plastic, mudbrick, ... | Structural engineering | Wikipedia | 61 | 45829 | https://en.wikipedia.org/wiki/Structural%20engineering | Technology | Disciplines | null | vital_articles |
Tetanus (), also known as lockjaw, is a bacterial infection caused by Clostridium tetani and characterized by muscle spasms. In the most common type, the spasms begin in the jaw and then progress to the rest of the body. Each spasm usually lasts for a few minutes. Spasms occur frequently for three to four weeks. Some s... | Tetanus | Wikipedia | 477 | 45831 | https://en.wikipedia.org/wiki/Tetanus | Biology and health sciences | Infectious disease | null | vital_articles |
Tetanus often begins with mild spasms in the jaw muscles—also known as lockjaw. Similar spasms can also be a feature of trismus. The spasms can also affect the facial muscles, resulting in an appearance called risus sardonicus. Chest, neck, back, abdominal muscles, and buttocks may be affected. Back muscle spasms often... | Tetanus | Wikipedia | 478 | 45831 | https://en.wikipedia.org/wiki/Tetanus | Biology and health sciences | Infectious disease | null | vital_articles |
Neonatal tetanus (trismus nascentium) is a form of generalized tetanus that occurs in newborns, usually those born to mothers who themselves have not been vaccinated. If the mother has been vaccinated against tetanus, the infants acquire passive immunity, and are thus protected. It usually occurs through infection of t... | Tetanus | Wikipedia | 500 | 45831 | https://en.wikipedia.org/wiki/Tetanus | Biology and health sciences | Infectious disease | null | vital_articles |
Tetanus is caused by the tetanus bacterium, Clostridium tetani. The disease is an international health problem, as C. tetani endospores are ubiquitous. Endospores can be introduced into the body through a puncture wound (penetrating trauma). Due to C. tetani being an anaerobic bacterium, it and its endospores thrive in... | Tetanus | Wikipedia | 463 | 45831 | https://en.wikipedia.org/wiki/Tetanus | Biology and health sciences | Infectious disease | null | vital_articles |
Tetanus neurotoxin (TeNT) binds to the presynaptic membrane of the neuromuscular junction, is internalized, and is transported back through the axon until it reaches the central nervous system. Here, it selectively binds to and is transported into inhibitory neurons via endocytosis. It then leaves the vesicle for the n... | Tetanus | Wikipedia | 410 | 45831 | https://en.wikipedia.org/wiki/Tetanus | Biology and health sciences | Infectious disease | null | vital_articles |
The toxin travels from the wound site to the neuromuscular junction through the bloodstream, where it binds to the presynaptic membrane of a motor neuron. The heavy chain C-terminal domain aids in binding to the correct site, recognizing and binding to the correct glycoproteins and glycolipids in the presynaptic membra... | Tetanus | Wikipedia | 480 | 45831 | https://en.wikipedia.org/wiki/Tetanus | Biology and health sciences | Infectious disease | null | vital_articles |
The light chain of the tetanus toxin is zinc-dependent protease. It shares a common zinc protease motif (His-Glu-Xaa-Xaa-His) that researchers hypothesized was essential for target cleavage until this was more recently confirmed by experiment: when all zinc was removed from the neuron with heavy metal chelators, the to... | Tetanus | Wikipedia | 454 | 45831 | https://en.wikipedia.org/wiki/Tetanus | Biology and health sciences | Infectious disease | null | vital_articles |
Tetanus can be prevented by vaccination with tetanus toxoid. The CDC recommends that adults receive a booster vaccine every ten years, and standard care practice in many places is to give the booster to any person with a puncture wound who is uncertain of when they were last vaccinated, or if they have had fewer than t... | Tetanus | Wikipedia | 506 | 45831 | https://en.wikipedia.org/wiki/Tetanus | Biology and health sciences | Infectious disease | null | vital_articles |
Severe tetanus
Severe cases will require admission to intensive care. In addition to the measures listed above for mild tetanus:
Human tetanus immunoglobulin injected intrathecally (which increases clinical improvement from 4% to 35%).
Tracheotomy and mechanical ventilation for 3 to 4 weeks. Tracheotomy is recommend... | Tetanus | Wikipedia | 421 | 45831 | https://en.wikipedia.org/wiki/Tetanus | Biology and health sciences | Infectious disease | null | vital_articles |
In 2013, it caused about 59,000 deaths—down from 356,000 in 1990. Tetanus, notably the neonatal form, remains a significant public health problem in non-industrialized countries, with 59,000 newborns dying worldwide in 2008 as a result of neonatal tetanus. In the United States, from 2000 through 2007, an average of 31 ... | Tetanus | Wikipedia | 501 | 45831 | https://en.wikipedia.org/wiki/Tetanus | Biology and health sciences | Infectious disease | null | vital_articles |
Research
There is insufficient evidence that tetanus can be treated or prevented by vitamin C. This is at least partially due to the fact that the historical trials that were conducted in attempts to look for a possible connection between vitamin C and alleviating tetanus patients were of poor quality. | Tetanus | Wikipedia | 58 | 45831 | https://en.wikipedia.org/wiki/Tetanus | Biology and health sciences | Infectious disease | null | vital_articles |
A loudspeaker (commonly referred to as a speaker or, more fully, a speaker system) is a combination of one or more speaker drivers, an enclosure, and electrical connections (possibly including a crossover network). The speaker driver is an electroacoustic transducer that converts an electrical audio signal into a corre... | Loudspeaker | Wikipedia | 322 | 45871 | https://en.wikipedia.org/wiki/Loudspeaker | Technology | Media and communication | null | vital_articles |
For a speaker to efficiently produce sound, especially at lower frequencies, the speaker driver must be baffled so that the sound emanating from its rear does not cancel out the (intended) sound from the front; this generally takes the form of a speaker enclosure or speaker cabinet, an often rectangular box made of woo... | Loudspeaker | Wikipedia | 386 | 45871 | https://en.wikipedia.org/wiki/Loudspeaker | Technology | Media and communication | null | vital_articles |
To adequately and accurately reproduce a wide range of frequencies with even coverage, most loudspeaker systems employ more than one driver, particularly for higher sound pressure level (SPL) or maximum accuracy. Individual drivers are used to reproduce different frequency ranges. The drivers are named subwoofers (for ... | Loudspeaker | Wikipedia | 287 | 45871 | https://en.wikipedia.org/wiki/Loudspeaker | Technology | Media and communication | null | vital_articles |
History
Johann Philipp Reis installed an electric loudspeaker in his telephone in 1861; it was capable of reproducing clear tones, but later revisions could also reproduce muffled speech. Alexander Graham Bell patented his first electric loudspeaker (a moving iron type capable of reproducing intelligible speech) as par... | Loudspeaker | Wikipedia | 459 | 45871 | https://en.wikipedia.org/wiki/Loudspeaker | Technology | Media and communication | null | vital_articles |
These first loudspeakers used electromagnets, because large, powerful permanent magnets were generally not available at a reasonable price. The coil of an electromagnet, called a field coil, was energized by a current through a second pair of connections to the driver. This winding usually served a dual role, acting al... | Loudspeaker | Wikipedia | 398 | 45871 | https://en.wikipedia.org/wiki/Loudspeaker | Technology | Media and communication | null | vital_articles |
Altec Lansing introduced the 604, which became their most famous coaxial Duplex driver, in 1943. It incorporated a high-frequency horn that sent sound through a hole in the pole piece of a 15-inch woofer for near-point-source performance. Altec's "Voice of the Theatre" loudspeaker system was first sold in 1945, offerin... | Loudspeaker | Wikipedia | 440 | 45871 | https://en.wikipedia.org/wiki/Loudspeaker | Technology | Media and communication | null | vital_articles |
Individual electrodynamic drivers provide their best performance within a limited frequency range. Multiple drivers (e.g. subwoofers, woofers, mid-range drivers, and tweeters) are generally combined into a complete loudspeaker system to provide performance beyond that constraint. The three most commonly used sound radi... | Loudspeaker | Wikipedia | 506 | 45871 | https://en.wikipedia.org/wiki/Loudspeaker | Technology | Media and communication | null | vital_articles |
A subwoofer is a woofer driver used only for the lowest-pitched part of the audio spectrum: typically below 200 Hz for consumer systems, below 100 Hz for professional live sound, and below 80 Hz in THX-approved systems. Because the intended range of frequencies is limited, subwoofer system design is usually simpler in ... | Loudspeaker | Wikipedia | 509 | 45871 | https://en.wikipedia.org/wiki/Loudspeaker | Technology | Media and communication | null | vital_articles |
Mid-range driver
A mid-range speaker is a loudspeaker driver that reproduces a band of frequencies generally between 1–6 kHz, otherwise known as the mid frequencies (between the woofer and tweeter). Mid-range driver diaphragms can be made of paper or composite materials and can be direct radiation drivers (rather lik... | Loudspeaker | Wikipedia | 410 | 45871 | https://en.wikipedia.org/wiki/Loudspeaker | Technology | Media and communication | null | vital_articles |
A passive crossover is an electronic circuit that uses a combination of one or more resistors, inductors and capacitors. These components are combined to form a filter network and are most often placed between the full frequency-range power amplifier and the loudspeaker drivers to divide the amplifier's signal into the... | Loudspeaker | Wikipedia | 297 | 45871 | https://en.wikipedia.org/wiki/Loudspeaker | Technology | Media and communication | null | vital_articles |
Passive crossovers are commonly installed inside speaker boxes and are by far the most common type of crossover for home and low-power use. In car audio systems, passive crossovers may be in a separate box, necessary to accommodate the size of the components used. Passive crossovers may be simple for low-order filterin... | Loudspeaker | Wikipedia | 499 | 45871 | https://en.wikipedia.org/wiki/Loudspeaker | Technology | Media and communication | null | vital_articles |
However, a rigid enclosure reflects sound internally, which can then be transmitted back through the loudspeaker diaphragm—again resulting in degradation of sound quality. This can be reduced by internal absorption using absorptive materials such as glass wool, wool, or synthetic fiber batting, within the enclosure. Th... | Loudspeaker | Wikipedia | 441 | 45871 | https://en.wikipedia.org/wiki/Loudspeaker | Technology | Media and communication | null | vital_articles |
The size of the throat, mouth, the length of the horn, as well as the area expansion rate along it must be carefully chosen to match the driver to properly provide this transforming function over a range of frequencies. The length and cross-sectional mouth area required to create a bass or sub-bass horn dictates a horn... | Loudspeaker | Wikipedia | 321 | 45871 | https://en.wikipedia.org/wiki/Loudspeaker | Technology | Media and communication | null | vital_articles |
Most home hi-fi loudspeakers use two wiring points to connect to the source of the signal (for example, to the audio amplifier or receiver). To accept the wire connection, the loudspeaker enclosure may have binding posts, spring clips, or a panel-mount jack. If the wires for a pair of speakers are not connected with re... | Loudspeaker | Wikipedia | 393 | 45871 | https://en.wikipedia.org/wiki/Loudspeaker | Technology | Media and communication | null | vital_articles |
Speaker specifications generally include:
Speaker or driver type (individual units only) – full-range, woofer, tweeter, or mid-range.
Size of individual drivers. For cone drivers, the quoted size is generally the outside diameter of the basket. However, it may less commonly also be the diameter of the cone surround, ... | Loudspeaker | Wikipedia | 483 | 45871 | https://en.wikipedia.org/wiki/Loudspeaker | Technology | Media and communication | null | vital_articles |
and optionally:
Crossover frequency(ies) (multi-driver systems only) – The nominal frequency boundaries of the division between drivers.
Frequency response – The measured, or specified, output over a specified range of frequencies for a constant input level varied across those frequencies. It sometimes includes a var... | Loudspeaker | Wikipedia | 356 | 45871 | https://en.wikipedia.org/wiki/Loudspeaker | Technology | Media and communication | null | vital_articles |
The load that a driver presents to an amplifier consists of a complex electrical impedance—a combination of resistance and both capacitive and inductive reactance, which combines properties of the driver, its mechanical motion, the effects of crossover components (if any are in the signal path between amplifier and dri... | Loudspeaker | Wikipedia | 367 | 45871 | https://en.wikipedia.org/wiki/Loudspeaker | Technology | Media and communication | null | vital_articles |
Efficiency vs. sensitivity
Loudspeaker efficiency is defined as the sound power output divided by the electrical power input. Most loudspeakers are inefficient transducers; only about 1% of the electrical energy sent by an amplifier to a typical home loudspeaker is converted to acoustic energy. The remainder is convert... | Loudspeaker | Wikipedia | 439 | 45871 | https://en.wikipedia.org/wiki/Loudspeaker | Technology | Media and communication | null | vital_articles |
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