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to support and extend the wing. Near the body, the humerus or upper arm bone is short but powerfully built. It sports a large deltopectoral crest, to which the major flight muscles are attached. Despite the considerable forces exerted on it, the humerus is hollow or pneumatised inside, reinforced by bone struts. The long bones of the lower arm, the ulna and radius, are much longer than the humerus. They were probably incapable of pronation. A bone unique to pterosaurs, known as the pteroid, connected to the wrist and helped to support the forward membrane (the propatagium) between the wrist and shoulder. Evidence of webbing between the three free fingers of the pterosaur forelimb suggests that this forward membrane may have been more extensive than the simple pteroid-to-shoulder connection traditionally depicted in life restorations. The position of the pteroid bone itself has been controversial. Some scientists, notably Matthew Wilkinson, have argued that the pteroid pointed forward, extending the forward membrane and allowing it to function as an adjustable flap. This view was contradicted in a 2007 paper by Chris Bennett, who showed that the pteroid did not articulate as previously thought and could not have pointed forward, but rather was directed inward toward the body as traditionally interpreted. Specimens of Changchengopterus pani and Darwinopterus linglongtaensis show the pteroid in articulation with the proximal syncarpal, suggesting that the pteroid articulated with the 'saddle' of the radiale (proximal syncarpal) and that both the pteroid and preaxial carpal were migrated centralia. The pterosaur wrist consists of two inner (proximal, at the side of the long bones of the arm) and four outer (distal, at the side of the hand) carpals (wrist bones), excluding the pteroid bone, which may itself be a modified distal carpal. The proximal carpals are fused together into a "syncarpal" in mature specimens, while three of the distal carpals fuse to form a distal syncarpal. The remaining distal carpal, referred to here as the medial carpal, but which has also been termed the distal lateral, or pre-axial carpal, articulates on a vertically elongate biconvex facet on the anterior surface of the distal syncarpal. The medial carpal bears a deep concave fovea that opens anteriorly, ventrally and somewhat medially, within which the pteroid articulates, according to Wilkinson. In derived pterodactyloids like pteranodontians and azhdarchoids, metacarpals I-III are small and do not connect to the carpus, instead hanging in contact with the fourth metacarpal. With these derived species, the fourth metacarpal has been enormously elongated, typically equalling or exceeding the length of the long bones of the lower arm. The fifth metacarpal had been lost. In all species, the first to third fingers are much smaller than the fourth, the "wingfinger", and contain two, three and four phalanges respectively. The smaller fingers are clawed, with the ungual size varying among species. In nyctosaurids the forelimb digits besides the wingfinger have been lost altogether. The wingfinger accounts for about half or more of the total wing length. It normally consists of four phalanges. Their relative lengths tend to vary among species, which has often been used to distinguish related forms. The fourth phalanx is usually the shortest. It lacks a claw and has been lost completely by nyctosaurids. It is curved to behind, resulting in a rounded wing tip, which reduces induced drag. The wingfinger is also bent somewhat downwards. When standing, pterosaurs probably rested on their metacarpals, with the outer wing folded to behind. In this position, the "anterior" sides of the metacarpals were rotated to the rear. This would point the smaller fingers obliquely to behind. According to Bennett, this would imply that the wingfinger, able to describe the largest arc of any wing element, up to 175°, was not folded by flexion but by an extreme extension. The wing was automatically folded when the elbow was bowed. A laser-simulated fluorescence scan on Pterodactylus also identified a membranous "fairing" (area conjunctioning the wing with the body at the neck), as opposed to the feathered or fur-composed "fairing" seen in birds and bats respectively. Pelvis The pelvis of pterosaurs was of moderate size compared to the body as a whole. Often the three pelvic bones were fused. The ilium was long and low, its front and rear blades projecting horizontally beyond the edges of the lower pelvic bones. Despite this length, the rod-like form of these processes indicates that the hindlimb muscles attached to them were limited in strength. The, in side view narrow, pubic bone fused with the broad ischium into an ischiopubic blade. Sometimes, the blades of both sides were also fused, closing the pelvis from below and forming the pelvic canal. The hip joint was not perforated and allowed considerable mobility to the leg. It was directed obliquely upwards, preventing a perfectly vertical position of the leg. The front of the pubic bones articulated with a unique structure, the paired prepubic bones. Together these formed a cusp covering the rear belly, between the pelvis and the belly ribs. The vertical mobility of this element suggests a function in breathing, compensating the relative rigidity of the chest cavity. Hindlimbs The hindlimbs of pterosaurs were strongly built, yet relative to their wingspans smaller than those of birds. They were long in comparison to the torso length. The thighbone was rather straight, with the head making only a small angle with the shaft. This implies that the legs were not held vertically below the body but were somewhat sprawling. The shinbone was often fused with the upper ankle bones into a tibiotarsus that was longer than the thighbone. It could attain a vertical position when walking. The calf bone tended to be slender, especially at its lower end that in advanced forms did not reach the ankle, sometimes reducing total length to a third. Typically it was fused to the shinbone. The ankle was a simple, "mesotarsal", hinge. The, rather long and slender, metatarsus was always splayed to some degree. The foot was plantigrade, meaning that during the walking cycle the sole of the metatarsus was pressed onto the soil. There was a clear difference between early pterosaurs and advanced species regarding the form of the fifth digit. Originally, the fifth metatarsal was robust and not very shortened. It was connected to the ankle in a higher position than the other metatarsals. It bore a long, and often curved, mobile clawless fifth toe consisting of two phalanges. The function of this element has been enigmatic. It used to be thought that the animals slept upside-down like bats, hanging from branches and using the fifth toes as hooks. Another hypothesis held that they stretched the brachiopatagia, but in articulated fossils the fifth digits are always flexed towards the tail. Later it became popular to assume that these toes extended an uropatagium or cruropatagium between them. As the fifth toes were on the outside of the feet, such a configuration would only have been possible if these rotated their fronts outwards in flight. Such a rotation could be caused by an abduction of the thighbone, meaning that the legs would be spread. This would also turn the feet into a vertical position. They then could act as rudders to control yaw. Some specimens show membranes between the toes, allowing them to function as flight control surfaces. The uropatagium or cruropatagium would control pitch. When walking the toes could flex upwards to lift the membrane from the ground. In Pterodactyloidea, the fifth metatarsal was much reduced and the fifth toe, if present, little more than a stub. This suggests that their membranes were split, increasing flight manoeuvrability. The first to fourth toes were long. They had two, three, four and five phalanges respectively. Often the third toe was longest; sometimes the fourth. Flat joints indicate a limited mobility. These toes were clawed but the claws were smaller than the hand claws. Soft tissues The rare conditions that allowed for the fossilisation of pterosaur remains, sometimes also preserved soft tissues. Modern synchrotron or ultraviolet light photography has revealed many traces not visible to the naked eye. These are often imprecisely called "impressions" but mostly consist of petrifications, natural casts and transformations of the original material. They may include horn crests, beaks or claw sheaths as well as the various flight membranes. Exceptionally, muscles were preserved. Skin patches show small round non-overlapping scales on the soles of the feet, the ankles and the ends of the metatarsals. They covered pads cushioning the impact of walking. Scales are unknown from other parts of the body. Pycnofibers Most or all pterosaurs had hair-like filaments known as pycnofibers on the head and torso. The term "pycnofiber", meaning "dense filament", was coined by palaeontologist Alexander Kellner and colleagues in 2009. Pycnofibers were unique structures similar to, but not homologous (sharing a common origin) with, mammalian hair, an example of convergent evolution. A fuzzy integument was first reported from a specimen of Scaphognathus crassirostris in 1831 by Georg August Goldfuss, but had been widely doubted. Since the 1990s, pterosaur finds and histological and ultraviolet examination of pterosaur specimens have provided incontrovertible proof: pterosaurs had pycnofiber coats. Sordes pilosus (which translates as "hairy demon") and Jeholopterus ninchengensis show pycnofibers on the head and body. The presence of pycnofibers strongly indicates that pterosaurs were endothermic (warm-blooded). They aided thermoregulation, as is common in warm-blooded animals who need insulation to prevent excessive heat-loss. Pycnofibers were flexible, short filaments, about five to seven millimetres long and rather simple in structure with a hollow central canal. Pterosaur pelts might have been comparable in density to many Mesozoic mammals. Relation with feathers Pterosaur filaments could share a common origin with feathers, as speculated in 2002 by Czerkas and Ji. In 2009, Kellner concluded that pycnofibers were structured similarly to theropod proto-feathers. Others were unconvinced, considering the difference with the "quills" found on many of the bird-like maniraptoran specimens too fundamental. A 2018 study of the remains of two small Jurassic-age pterosaurs from Inner Mongolia, China, found that pterosaurs had a wide array of pycnofiber shapes and structures, as opposed to the homogeneous structures that had generally been assumed to cover them. Some of these had frayed ends, very similar in structure to four different feather types known from birds or other dinosaurs but almost never known from pterosaurs prior to the study, suggesting homology. A response to this study was published in 2020, where it was suggested that the structures seen on the anurognathids were actually a result of the decomposition of aktinofibrils: a type of fibre used to strengthen and stiffen the wing. However, in a response to this, the authors of the 2018 paper point to the fact that the presence of the structures extend past the patagium, and the presence of both aktinofibrils and filaments on Jeholopterus ningchengensis and Sordes pilosus. The various forms of filament structure present on the anurognathids in the 2018 study would also require a form of decomposition that would cause the different 'filament' forms seen. They therefore conclude that the most parsimonious interpretation of the structures is that they are filamentous proto-feathers. But Liliana D’Alba points out that the description of the preserved integumentary structures on the two anurogmathid specimens is still based upon gross morphology. She also points out that Pterorhynchus was described to have feathers to support the claim that feathers had a common origin with Ornithodirans but was argued against by several authors. The only method to assure if it was homologous to feathers is to use a scanning electron microscope. History of discovery First finds Pterosaur fossils are very rare, due to their light bone construction. Complete skeletons can generally only be found in geological layers with exceptional preservation conditions, the so-called Lagerstätten. The pieces from one such Lagerstätte, the Late Jurassic Solnhofen Limestone in Bavaria, became much sought after by rich collectors. In 1784, the Italian naturalist Cosimo Alessandro Collini was the first scientist in history to describe a pterosaur fossil. At that time the concepts of evolution and extinction were only imperfectly developed. The bizarre build of the pterosaur was therefore shocking, as it could not clearly be assigned to any existing animal group. The discovery of pterosaurs would thus play an important role in the progress of modern paleontology and geology. If such creatures were still alive, only the sea was a credible habitat and Collini suggested it might be a swimming animal that used its long front limbs as paddles. A few scientists continued to support the aquatic interpretation even until 1830, when the German zoologist Johann Georg Wagler suggested that Pterodactylus used its wings as flippers and was affiliated with Ichthyosauria and Plesiosauria. In 1800, Johann Hermann first suggested that it represented a flying creature in a letter to Georges Cuvier. Cuvier agreed in 1801, understanding it was an extinct flying reptile. In 1809, he coined the name Ptéro-Dactyle, "wing-finger". This was in 1815 Latinised to Pterodactylus. At first most species were assigned to this genus and ultimately "pterodactyl" was popularly and incorrectly applied to all members of Pterosauria. Today, paleontologists limit the term to the genus Pterodactylus or members of the Pterodactyloidea. In 1812 and 1817, Samuel Thomas von Soemmerring redescribed the original specimen and an additional one. He saw them as affiliated to birds and bats. Although he was mistaken in this, his "bat model" would be very influential during the 19th century. In 1843, Edward Newman thought pterosaurs were flying marsupials. As the bat model correctly depicted pterosaurs as furred and warm-blooded, it better approached the true physiology of pterosaurs than Cuvier's "reptile model". In 1834, Johann Jakob Kaup coined the term Pterosauria. Expanding research In 1828, Mary Anning found in England the first pterosaur genus outside Germany, named as Dimorphodon by Richard Owen, also the first non-pterodactyloid pterosaur known. Later in the century, the Early Cretaceous Cambridge Greensand produced thousands of pterosaur fossils, that however, were of poor quality, consisting mostly of strongly eroded fragments. Based on these, nevertheless numerous genera and species would be named. Many were described by Harry Govier Seeley, at the time the main English expert on the subject, who also wrote the first pterosaur book, Ornithosauria, and in 1901 the first popular book, Dragons of the Air. Seeley thought that pterosaurs were warm-blooded and dynamic creatures, closely related to birds. Earlier, the evolutionist St. George Jackson Mivart had suggested pterosaurs were the direct ancestors of birds. Owen opposed the views of both men, seeing pterosaurs as cold-blooded "true" reptiles. In the US, Othniel Charles Marsh in 1870 discovered Pteranodon in the Niobrara Chalk, then the largest known pterosaur, the first toothless one and the first from America. These layers too rendered thousands of fossils, also including relatively complete skeletons that were three-dimensionally preserved instead of being strongly compressed as with the Solnhofen specimens. This led to a much better understanding of many anatomical details, such as the hollow nature of the bones. Meanwhile, finds from the Solnhofen had continued, accounting for the majority of complete high quality specimens discovered. They allowed to identify most new basal taxa, such as Rhamphorhynchus, Scaphognathus and Dorygnathus. This material gave birth to a German school of pterosaur research, which saw flying reptiles as the warm-blooded, furry and active Mesozoic counterparts of modern bats and birds. In 1882, Marsh and Karl Alfred Zittel published studies about the wing membranes of specimens of Rhamphorhynchus. German studies continued well into the 1930s, describing new species such as Anurognathus. In 1927, Ferdinand Broili discovered hair follicles in pterosaur skin, and paleoneurologist Tilly Edinger determined that the brains of pterosaurs more resembled those of birds than modern cold-blooded reptiles. In contrast, English and American paleontologists by the middle of the twentieth century largely lost interest in pterosaurs. They saw them as failed evolutionary experiments, cold-blooded and scaly, that hardly could fly, the larger species only able to glide, being forced to climb trees or throw themselves from cliffs to achieve a take-off. In 1914, for the first time pterosaur aerodynamics were quantitatively analysed, by Ernest Hanbury Hankin and David Meredith Seares Watson, but they interpreted Pteranodon as a pure glider. Little research was done on the group during the 1940s and 1950s. Pterosaur renaissance The situation for dinosaurs was comparable. From the 1960s onwards, a dinosaur renaissance took place, a quick increase in the number of studies and critical ideas, influenced by the discovery of additional fossils of Deinonychus, whose spectacular traits refuted what had become entrenched orthodoxy. In 1970, likewise the description of the furry pterosaur Sordes began what Robert Bakker named a renaissance of pterosaurs. Especially Kevin Padian propagated the new views, publishing a series of studies depicting pterosaurs as warm-blooded, active and running animals. This coincided with a revival of the German school through the work of Peter Wellnhofer, who in 1970s laid the foundations of modern pterosaur science. In 1978, he published the first pterosaur textbook, the Handbuch der Paläoherptologie, Teil 19: Pterosauria, and in 1991 the second ever popular science pterosaur book, the Encyclopedia of Pterosaurs. This development accelerated through the exploitation of two new Lagerstätten. During the 1970s, the Early Cretaceous Santana Formation in Brazil began to produce chalk nodules that, though often limited in size and the completeness of the fossils they contained, perfectly preserved three-dimensional pterosaur skeletal parts. German and Dutch institutes bought such nodules from fossil poachers and prepared them in Europe, allowing their scientists to describe many new species and revealing a whole new fauna. Soon, Brazilian researchers, among them Alexander Kellner, intercepted the trade and named even more species. Even more productive was the Early Cretaceous Chinese Jehol Biota of Liaoning that since the 1990s has brought forth hundreds of exquisitely preserved two-dimensional fossils, often showing soft tissue remains. Chinese researchers such as Lü Junchang have again named many new taxa. As discoveries also increased in other parts of the world, a sudden surge in the total of named genera took place. By 2009, when they had increased to about ninety, this growth showed no sign of levelling-off. In 2013, M.P. Witton indicated that the number of discovered pterosaur species had risen to 130. Over ninety percent of known taxa has been named during the "renaissance". Many of these were from groups the existence of which had been unknown. Advances in computing power allowed to determine their complex relationships through the quantitative method of cladistics. New and old fossils yielded much more information when subjected to modern ultraviolet light or roentgen photography, or CAT-scans. Insights from other fields of biology were applied to the data obtained. All this resulted in a substantial progress in pterosaur research, rendering older accounts in popular science books completely outdated. In 2017 a fossil from a 170-million-year-old pterosaur was discovered on the Isle of Skye in Scotland. The National Museum of Scotland claims that it the largest of its kind ever discovered from the Jurassic period, and it has been described as the world’s best-preserved skeleton of a pterosaur. Evolution and extinction Origins Because pterosaur anatomy has been so heavily modified for flight, and immediate transitional fossil predecessors have not so far been described, the ancestry of pterosaurs is not fully understood. The oldest known pterosaurs were already fully adapted to a flying lifestyle. Since Seeley, it was recognised that pterosaurs were likely to have had their origin in the "archosaurs", what today would be called the Archosauromorpha. In the 1980s, early cladistic analyses found that they were Avemetatarsalians (archosaurs closer to dinosaurs than to crocodilians). As this would make them also rather close relatives of the dinosaurs, these results were seen by Kevin Padian as confirming his interpretation of pterosaurs as bipedal warm-blooded animals. Because these early analyses were based on a limited number of taxa and characters, their results were inherently uncertain. Several influential researchers who rejected Padian's conclusions offered alternative hypotheses. David Unwin proposed an ancestry among the basal Archosauromorpha, specifically long-necked forms ("protorosaurs") such as tanystropheids. A placement among basal archosauriforms like Euparkeria was also suggested. Some basal archosauromorphs seem at first glance to be good candidates for close pterosaur relatives due to their long-limbed anatomy; one example is Sharovipteryx, a "protorosaur" with skin membranes on its hindlimbs likely used for gliding. A 1999 study by Michael Benton found that pterosaurs were avemetatarsalians closely related to Scleromochlus, and named the group Ornithodira to encompass pterosaurs and dinosaurs. Two researchers, S. Christopher Bennett in 1996, and paleoartist David Peters in 2000, published analyses finding pterosaurs to be protorosaurs or closely related to them. However, Peters gathered novel anatomical data using an unverified technique called "Digital Graphic Segregation" (DGS), which involves digitally tracing over images of pterosaur fossils using photo editing software. Bennett only recovered pterosaurs as close relatives of the protorosaurs after removing characteristics of the hindlimb from his analysis, to test the possibility of locomotion-based convergent evolution between pterosaurs and dinosaurs. A 2007 reply by Dave Hone and Michael Benton could not reproduce this result, finding pterosaurs to be closely related to dinosaurs even without hindlimb characters. They also criticized David Peters for drawing conclusions without access to the primary evidence, that is, the pterosaur fossils themselves. Hone and Benton concluded that, although more basal pterosauromorphs are needed to clarify their relationships, current evidence indicates that pterosaurs are avemetatarsalians, as either the sister group of Scleromochlus or a branch between the latter and Lagosuchus. An 2011 archosaur-focused phylogenetic analysis by Sterling Nesbitt benefited from far more data and found strong support for pterosaurs being avemetatarsalians, though Scleromochlus was not included due to its poor preservation. A 2016 archosauromorph-focused study by Martin Ezcurra included various proposed pterosaur relatives, yet also found pterosaurs to be closer to dinosaurs and unrelated to more basal taxa. Working from his 1996 analysis, Bennett published a 2020 study on Scleromochlus which argued that both Scleromochlus and pterosaurs were non-archosaur archosauromorphs, albeit not particularly closely related to each other. By contrast, a later 2020 study proposed that lagerpetid archosaurs were the sister clade to pterosauria. This was based on newly described fossil skulls and forelimbs showing various anatomical similarities with pterosaurs and reconstructions of lagerpetid brains and sensory systems based on CT scans also showing neuroanatomical similarities with pterosaurs. The results of the latter study were subsequently supported by an independent analysis of early pterosauromorph interrelationships. A related problem is the origin of pterosaur flight. Like with birds, hypotheses can be ordered into two main varieties: "ground up" or	sides were also fused, closing the pelvis from below and forming the pelvic canal. The hip joint was not perforated and allowed considerable mobility to the leg. It was directed obliquely upwards, preventing a perfectly vertical position of the leg. The front of the pubic bones articulated with a unique structure, the paired prepubic bones. Together these formed a cusp covering the rear belly, between the pelvis and the belly ribs. The vertical mobility of this element suggests a function in breathing, compensating the relative rigidity of the chest cavity. Hindlimbs The hindlimbs of pterosaurs were strongly built, yet relative to their wingspans smaller than those of birds. They were long in comparison to the torso length. The thighbone was rather straight, with the head making only a small angle with the shaft. This implies that the legs were not held vertically below the body but were somewhat sprawling. The shinbone was often fused with the upper ankle bones into a tibiotarsus that was longer than the thighbone. It could attain a vertical position when walking. The calf bone tended to be slender, especially at its lower end that in advanced forms did not reach the ankle, sometimes reducing total length to a third. Typically it was fused to the shinbone. The ankle was a simple, "mesotarsal", hinge. The, rather long and slender, metatarsus was always splayed to some degree. The foot was plantigrade, meaning that during the walking cycle the sole of the metatarsus was pressed onto the soil. There was a clear difference between early pterosaurs and advanced species regarding the form of the fifth digit. Originally, the fifth metatarsal was robust and not very shortened. It was connected to the ankle in a higher position than the other metatarsals. It bore a long, and often curved, mobile clawless fifth toe consisting of two phalanges. The function of this element has been enigmatic. It used to be thought that the animals slept upside-down like bats, hanging from branches and using the fifth toes as hooks. Another hypothesis held that they stretched the brachiopatagia, but in articulated fossils the fifth digits are always flexed towards the tail. Later it became popular to assume that these toes extended an uropatagium or cruropatagium between them. As the fifth toes were on the outside of the feet, such a configuration would only have been possible if these rotated their fronts outwards in flight. Such a rotation could be caused by an abduction of the thighbone, meaning that the legs would be spread. This would also turn the feet into a vertical position. They then could act as rudders to control yaw. Some specimens show membranes between the toes, allowing them to function as flight control surfaces. The uropatagium or cruropatagium would control pitch. When walking the toes could flex upwards to lift the membrane from the ground. In Pterodactyloidea, the fifth metatarsal was much reduced and the fifth toe, if present, little more than a stub. This suggests that their membranes were split, increasing flight manoeuvrability. The first to fourth toes were long. They had two, three, four and five phalanges respectively. Often the third toe was longest; sometimes the fourth. Flat joints indicate a limited mobility. These toes were clawed but the claws were smaller than the hand claws. Soft tissues The rare conditions that allowed for the fossilisation of pterosaur remains, sometimes also preserved soft tissues. Modern synchrotron or ultraviolet light photography has revealed many traces not visible to the naked eye. These are often imprecisely called "impressions" but mostly consist of petrifications, natural casts and transformations of the original material. They may include horn crests, beaks or claw sheaths as well as the various flight membranes. Exceptionally, muscles were preserved. Skin patches show small round non-overlapping scales on the soles of the feet, the ankles and the ends of the metatarsals. They covered pads cushioning the impact of walking. Scales are unknown from other parts of the body. Pycnofibers Most or all pterosaurs had hair-like filaments known as pycnofibers on the head and torso. The term "pycnofiber", meaning "dense filament", was coined by palaeontologist Alexander Kellner and colleagues in 2009. Pycnofibers were unique structures similar to, but not homologous (sharing a common origin) with, mammalian hair, an example of convergent evolution. A fuzzy integument was first reported from a specimen of Scaphognathus crassirostris in 1831 by Georg August Goldfuss, but had been widely doubted. Since the 1990s, pterosaur finds and histological and ultraviolet examination of pterosaur specimens have provided incontrovertible proof: pterosaurs had pycnofiber coats. Sordes pilosus (which translates as "hairy demon") and Jeholopterus ninchengensis show pycnofibers on the head and body. The presence of pycnofibers strongly indicates that pterosaurs were endothermic (warm-blooded). They aided thermoregulation, as is common in warm-blooded animals who need insulation to prevent excessive heat-loss. Pycnofibers were flexible, short filaments, about five to seven millimetres long and rather simple in structure with a hollow central canal. Pterosaur pelts might have been comparable in density to many Mesozoic mammals. Relation with feathers Pterosaur filaments could share a common origin with feathers, as speculated in 2002 by Czerkas and Ji. In 2009, Kellner concluded that pycnofibers were structured similarly to theropod proto-feathers. Others were unconvinced, considering the difference with the "quills" found on many of the bird-like maniraptoran specimens too fundamental. A 2018 study of the remains of two small Jurassic-age pterosaurs from Inner Mongolia, China, found that pterosaurs had a wide array of pycnofiber shapes and structures, as opposed to the homogeneous structures that had generally been assumed to cover them. Some of these had frayed ends, very similar in structure to four different feather types known from birds or other dinosaurs but almost never known from pterosaurs prior to the study, suggesting homology. A response to this study was published in 2020, where it was suggested that the structures seen on the anurognathids were actually a result of the decomposition of aktinofibrils: a type of fibre used to strengthen and stiffen the wing. However, in a response to this, the authors of the 2018 paper point to the fact that the presence of the structures extend past the patagium, and the presence of both aktinofibrils and filaments on Jeholopterus ningchengensis and Sordes pilosus. The various forms of filament structure present on the anurognathids in the 2018 study would also require a form of decomposition that would cause the different 'filament' forms seen. They therefore conclude that the most parsimonious interpretation of the structures is that they are filamentous proto-feathers. But Liliana D’Alba points out that the description of the preserved integumentary structures on the two anurogmathid specimens is still based upon gross morphology. She also points out that Pterorhynchus was described to have feathers to support the claim that feathers had a common origin with Ornithodirans but was argued against by several authors. The only method to assure if it was homologous to feathers is to use a scanning electron microscope. History of discovery First finds Pterosaur fossils are very rare, due to their light bone construction. Complete skeletons can generally only be found in geological layers with exceptional preservation conditions, the so-called Lagerstätten. The pieces from one such Lagerstätte, the Late Jurassic Solnhofen Limestone in Bavaria, became much sought after by rich collectors. In 1784, the Italian naturalist Cosimo Alessandro Collini was the first scientist in history to describe a pterosaur fossil. At that time the concepts of evolution and extinction were only imperfectly developed. The bizarre build of the pterosaur was therefore shocking, as it could not clearly be assigned to any existing animal group. The discovery of pterosaurs would thus play an important role in the progress of modern paleontology and geology. If such creatures were still alive, only the sea was a credible habitat and Collini suggested it might be a swimming animal that used its long front limbs as paddles. A few scientists continued to support the aquatic interpretation even until 1830, when the German zoologist Johann Georg Wagler suggested that Pterodactylus used its wings as flippers and was affiliated with Ichthyosauria and Plesiosauria. In 1800, Johann Hermann first suggested that it represented a flying creature in a letter to Georges Cuvier. Cuvier agreed in 1801, understanding it was an extinct flying reptile. In 1809, he coined the name Ptéro-Dactyle, "wing-finger". This was in 1815 Latinised to Pterodactylus. At first most species were assigned to this genus and ultimately "pterodactyl" was popularly and incorrectly applied to all members of Pterosauria. Today, paleontologists limit the term to the genus Pterodactylus or members of the Pterodactyloidea. In 1812 and 1817, Samuel Thomas von Soemmerring redescribed the original specimen and an additional one. He saw them as affiliated to birds and bats. Although he was mistaken in this, his "bat model" would be very influential during the 19th century. In 1843, Edward Newman thought pterosaurs were flying marsupials. As the bat model correctly depicted pterosaurs as furred and warm-blooded, it better approached the true physiology of pterosaurs than Cuvier's "reptile model". In 1834, Johann Jakob Kaup coined the term Pterosauria. Expanding research In 1828, Mary Anning found in England the first pterosaur genus outside Germany, named as Dimorphodon by Richard Owen, also the first non-pterodactyloid pterosaur known. Later in the century, the Early Cretaceous Cambridge Greensand produced thousands of pterosaur fossils, that however, were of poor quality, consisting mostly of strongly eroded fragments. Based on these, nevertheless numerous genera and species would be named. Many were described by Harry Govier Seeley, at the time the main English expert on the subject, who also wrote the first pterosaur book, Ornithosauria, and in 1901 the first popular book, Dragons of the Air. Seeley thought that pterosaurs were warm-blooded and dynamic creatures, closely related to birds. Earlier, the evolutionist St. George Jackson Mivart had suggested pterosaurs were the direct ancestors of birds. Owen opposed the views of both men, seeing pterosaurs as cold-blooded "true" reptiles. In the US, Othniel Charles Marsh in 1870 discovered Pteranodon in the Niobrara Chalk, then the largest known pterosaur, the first toothless one and the first from America. These layers too rendered thousands of fossils, also including relatively complete skeletons that were three-dimensionally preserved instead of being strongly compressed as with the Solnhofen specimens. This led to a much better understanding of many anatomical details, such as the hollow nature of the bones. Meanwhile, finds from the Solnhofen had continued, accounting for the majority of complete high quality specimens discovered. They allowed to identify most new basal taxa, such as Rhamphorhynchus, Scaphognathus and Dorygnathus. This material gave birth to a German school of pterosaur research, which saw flying reptiles as the warm-blooded, furry and active Mesozoic counterparts of modern bats and birds. In 1882, Marsh and Karl Alfred Zittel published studies about the wing membranes of specimens of Rhamphorhynchus. German studies continued well into the 1930s, describing new species such as Anurognathus. In 1927, Ferdinand Broili discovered hair follicles in pterosaur skin, and paleoneurologist Tilly Edinger determined that the brains of pterosaurs more resembled those of birds than modern cold-blooded reptiles. In contrast, English and American paleontologists by the middle of the twentieth century largely lost interest in pterosaurs. They saw them as failed evolutionary experiments, cold-blooded and scaly, that hardly could fly, the larger species only able to glide, being forced to climb trees or throw themselves from cliffs to achieve a take-off. In 1914, for the first time pterosaur aerodynamics were quantitatively analysed, by Ernest Hanbury Hankin and David Meredith Seares Watson, but they interpreted Pteranodon as a pure glider. Little research was done on the group during the 1940s and 1950s. Pterosaur renaissance The situation for dinosaurs was comparable. From the 1960s onwards, a dinosaur renaissance took place, a quick increase in the number of studies and critical ideas, influenced by the discovery of additional fossils of Deinonychus, whose spectacular traits refuted what had become entrenched orthodoxy. In 1970, likewise the description of the furry pterosaur Sordes began what Robert Bakker named a renaissance of pterosaurs. Especially Kevin Padian propagated the new views, publishing a series of studies depicting pterosaurs as warm-blooded, active and running animals. This coincided with a revival of the German school through the work of Peter Wellnhofer, who in 1970s laid the foundations of modern pterosaur science. In 1978, he published the first pterosaur textbook, the Handbuch der Paläoherptologie, Teil 19: Pterosauria, and in 1991 the second ever popular science pterosaur book, the Encyclopedia of Pterosaurs. This development accelerated through the exploitation of two new Lagerstätten. During the 1970s, the Early Cretaceous Santana Formation in Brazil began to produce chalk nodules that, though often limited in size and the completeness of the fossils they contained, perfectly preserved three-dimensional pterosaur skeletal parts. German and Dutch institutes bought such nodules from fossil poachers and prepared them in Europe, allowing their scientists to describe many new species and revealing a whole new fauna. Soon, Brazilian researchers, among them Alexander Kellner, intercepted the trade and named even more species. Even more productive was the Early Cretaceous Chinese Jehol Biota of Liaoning that since the 1990s has brought forth hundreds of exquisitely preserved two-dimensional fossils, often showing soft tissue remains. Chinese researchers such as Lü Junchang have again named many new taxa. As discoveries also increased in other parts of the world, a sudden surge in the total of named genera took place. By 2009, when they had increased to about ninety, this growth showed no sign of levelling-off. In 2013, M.P. Witton indicated that the number of discovered pterosaur species had risen to 130. Over ninety percent of known taxa has been named during the "renaissance". Many of these were from groups the existence of which had been unknown. Advances in computing power allowed to determine their complex relationships through the quantitative method of cladistics. New and old fossils yielded much more information when subjected to modern ultraviolet light or roentgen photography, or CAT-scans. Insights from other fields of biology were applied to the data obtained. All this resulted in a substantial progress in pterosaur research, rendering older accounts in popular science books completely outdated. In 2017 a fossil from a 170-million-year-old pterosaur was discovered on the Isle of Skye in Scotland. The National Museum of Scotland claims that it the largest of its kind ever discovered from the Jurassic period, and it has been described as the world’s best-preserved skeleton of a pterosaur. Evolution and extinction Origins Because pterosaur anatomy has been so heavily modified for flight, and immediate transitional fossil predecessors have not so far been described, the ancestry of pterosaurs is not fully understood. The oldest known pterosaurs were already fully adapted to a flying lifestyle. Since Seeley, it was recognised that pterosaurs were likely to have had their origin in the "archosaurs", what today would be called the Archosauromorpha. In the 1980s, early cladistic analyses found that they were Avemetatarsalians (archosaurs closer to dinosaurs than to crocodilians). As this would make them also rather close relatives of the dinosaurs, these results were seen by Kevin Padian as confirming his interpretation of pterosaurs as bipedal warm-blooded animals. Because these early analyses were based on a limited number of taxa and characters, their results were inherently uncertain. Several influential researchers who rejected Padian's conclusions offered alternative hypotheses. David Unwin proposed an ancestry among the basal Archosauromorpha, specifically long-necked forms ("protorosaurs") such as tanystropheids. A placement among basal archosauriforms like Euparkeria was also suggested. Some basal archosauromorphs seem at first glance to be good candidates for close pterosaur relatives due to their long-limbed anatomy; one example is Sharovipteryx, a "protorosaur" with skin membranes on its hindlimbs likely used for gliding. A 1999 study by Michael Benton found that pterosaurs were avemetatarsalians closely related to Scleromochlus, and named the group Ornithodira to encompass pterosaurs and dinosaurs. Two researchers, S. Christopher Bennett in 1996, and paleoartist David Peters in 2000, published analyses finding pterosaurs to be protorosaurs or closely related to them. However, Peters gathered novel anatomical data using an unverified technique called "Digital Graphic Segregation" (DGS), which involves digitally tracing over images of pterosaur fossils using photo editing software. Bennett only recovered pterosaurs as close relatives of the protorosaurs after removing characteristics of the hindlimb from his analysis, to test the possibility of locomotion-based convergent evolution between pterosaurs and dinosaurs. A 2007 reply by Dave Hone and Michael Benton could not reproduce this result, finding pterosaurs to be closely related to dinosaurs even without hindlimb characters. They also criticized David Peters for drawing conclusions without access to the primary evidence, that is, the pterosaur fossils themselves. Hone and Benton concluded that, although more basal pterosauromorphs are needed to clarify their relationships, current evidence indicates that pterosaurs are avemetatarsalians, as either the sister group of Scleromochlus or a branch between the latter and Lagosuchus. An 2011 archosaur-focused phylogenetic analysis by Sterling Nesbitt benefited from far more data and found strong support for pterosaurs being avemetatarsalians, though Scleromochlus was not included due to its poor preservation. A 2016 archosauromorph-focused study by Martin Ezcurra included various proposed pterosaur relatives, yet also found pterosaurs to be closer to dinosaurs and unrelated to more basal taxa. Working from his 1996 analysis, Bennett published a 2020 study on Scleromochlus which argued that both Scleromochlus and pterosaurs were non-archosaur archosauromorphs, albeit not particularly closely related to each other. By contrast, a later 2020 study proposed that lagerpetid archosaurs were the sister clade to pterosauria. This was based on newly described fossil skulls and forelimbs showing various anatomical similarities with pterosaurs and reconstructions of lagerpetid brains and sensory systems based on CT scans also showing neuroanatomical similarities with pterosaurs. The results of the latter study were subsequently supported by an independent analysis of early pterosauromorph interrelationships. A related problem is the origin of pterosaur flight. Like with birds, hypotheses can be ordered into two main varieties: "ground up" or "tree down". Climbing a tree would cause height and gravity provide both the energy and a strong selection pressure for incipient flight. Rupert Wild in 1983 proposed a hypothetical "propterosaurus": a lizard-like arboreal animal developing a membrane between its limbs, first to safely parachute and then, gradually elongating the fourth finger, to glide. However, subsequent cladistic results did not fit this model well. Neither protorosaurs nor ornithodirans are biologically equivalent to lizards. Furthermore, the transition between gliding and flapping flight is not well-understood. More recent studies on basal pterosaur hindlimb morphology seem to vindicate a connection to Scleromochlus. Like this archosaur, basal pterosaur lineages have plantigrade hindlimbs that show adaptations for saltation. Extinction It was once thought that competition with early bird species might have resulted in the extinction of many of the pterosaurs. Part of this is due to the fact it used to be thought that by the end of the Cretaceous, only large species of pterosaurs were present (no longer true; see below). The smaller species were thought to have become extinct, their niche filled by birds. However, pterosaur decline (if actually present) seems unrelated to bird diversity, as ecological overlap between the two groups appears to be minimal. In fact, at least some avian niches were reclaimed by pterosaurs prior to the KT event. At the end of the Cretaceous period, the Cretaceous–Paleogene extinction event, which wiped out all non-avian dinosaurs and most avian dinosaurs as well, and many other animals, seems also to have taken the pterosaurs. In the early 2010s, several new pterosaur taxa were discovered dating to the Campanian/Maastrichtian, such as the ornithocheirids Piksi and "Ornithocheirus", possible pteranodontids and nyctosaurids, several tapejarids and the indeterminate non-azhdarchid Navajodactylus. Small azhdarchoid pterosaurs were also present in the Campanian. This suggests that late Cretaceous pterosaur faunas were far more diverse than previously thought, possibly not even having declined significantly from the early Cretaceous. Small-sized pterosaur species apparently were present in the Csehbánya Formation, indicating a higher diversity of Late Cretaceous pterosaurs than previously accounted for. The recent findings of a small cat-sized adult azhdarchid further indicate that small pterosaurs from the Late Cretaceous might actually have simply been rarely preserved in the fossil record, helped by the fact that there is a strong bias against terrestrial small sized vertebrates such as juvenile dinosaurs, and that their diversity might actually have been much larger than previously thought. At least some non-pterodactyloid pterosaurs survived into the Late Cretaceous, postulating a Lazarus taxa situation for late Cretaceous pterosaur faunas. A 2021 study showcases that niches previously occupied by small pterosaurs were increasingly occupied by the juvenile stages of larger species in the Late Cretaceous. Rather than outcompeted by birds, pterosaurs essentially specialized a trend already occurring in previous eras of the Mesozoic. Classification and phylogeny In phylogenetic taxonomy, the clade Pterosauria has usually been defined as node-based and anchored to several extensively studied taxa as well as those thought to be primitive. One 2003 study defined Pterosauria as "The most recent common ancestor of the Anurognathidae, Preondactylus and Quetzalcoatlus and all their descendants." However, these types of definition would inevitably leave any related species that are slightly more primitive out of the Pterosauria. To remedy this, a new definition was proposed that would anchor the name not to any particular species but to an anatomical feature, the presence of an enlarged fourth finger that supports a wing membrane. This "apomorophy-based" definition was adopted by the PhyloCode in 2020 as "[T]he clade characterized by the apomorphy fourth manual digit hypertrophied to support a wing membrane, as inherited by Pterodactylus (originally Ornithocephalus) antiquus (Sömmerring 1812)". A broader clade, Pterosauromorpha, has been defined as all ornithodirans more closely related to pterosaurs than to dinosaurs. The internal classification of pterosaurs has historically been difficult, because there were many gaps in the fossil record. Starting from the 21st century, new discoveries are now filling in these gaps and giving a better picture of the evolution of pterosaurs. Traditionally, they were organized into two suborders: the Rhamphorhynchoidea, a "primitive" group of long-tailed pterosaurs, and the Pterodactyloidea, "advanced" pterosaurs with short tails. However, this traditional division has been largely abandoned. Rhamphorhynchoidea is a paraphyletic (unnatural) group, since the pterodactyloids evolved directly from them and not from a common ancestor, so, with the increasing use of cladistics, it has fallen out of favor among most scientists. The precise relationships between pterosaurs is still unsettled. Many studies of pterosaur relationships in the past have included limited data and were highly contradictory. However, newer studies using larger data sets are beginning to make things clearer. The cladogram (family tree) below follows a phylogenetic analysis presented by Longrich, Martill and Andres in 2018, with clade names after Andres et al. (2014). Paleobiology Flight The mechanics of pterosaur flight are not completely understood or modeled at this time. Katsufumi Sato, a Japanese scientist, did calculations using modern birds and concluded that it was impossible for a pterosaur to stay aloft. In the book Posture, Locomotion, and Paleoecology of Pterosaurs it is theorized that they were able to fly due to the oxygen-rich, dense atmosphere of the Late Cretaceous period. However, both Sato and the authors of Posture, Locomotion, and Paleoecology of Pterosaurs based their research on the now-outdated theories of pterosaurs being seabird-like, and the size limit does not apply to terrestrial pterosaurs, such as azhdarchids and tapejarids. Furthermore, Darren Naish concluded that atmospheric differences between the present and the Mesozoic were not needed for the giant size of pterosaurs. Another issue that has been difficult to understand is how they took off. Earlier suggestions were that pterosaurs were largely cold-blooded gliding animals, deriving warmth from the environment like modern lizards, rather than burning calories. In this case, it was unclear how the larger ones of enormous size, with an inefficient cold-blooded
record, allowing for detailed descriptions of their anatomy and analysis of their life history. Over 1,000 specimens have been identified, though less than half are complete enough to give researchers good anatomical information. Still, this is more fossils material than is known for any other pterosaur, and it includes both male and female specimens of various age groups and possibly species. Adult Pteranodon specimens from the two major species can be divided into two distinct size classes. The smaller class of specimens have small, rounded head crests and very wide pelvic canals, even wider than those of the much larger size class. The size of the pelvic canal probably allowed the laying of eggs, indicating that these smaller adults are females. The larger size class, representing male individuals, have narrow hips and very large crests, which were probably for display. Adult male Pteranodon were among the largest pterosaurs, and were the largest flying animals known until the late 20th century, when the giant azhdarchid pterosaurs were discovered. The wingspan of an average adult male Pteranodon was . Adult females were much smaller, averaging in wingspan. The largest specimen of Pteranodon longiceps from the Niobrara Formation measured from wingtip to wingtip. An even larger specimen is known from the Pierre Shale Formation, with a wingspan of , though this specimen may belong to the distinct genus and species Geosternbergia maysei. While most specimens are found crushed, enough fossils exist to put together a detailed description of the animal. Methods used to estimate the mass of large male Pteranodon specimens (those with wingspans of about 7 meters) have been notoriously unreliable, producing a wide range of estimates. In a review of pterosaur size estimates published in 2010, researchers Mark Witton and Mike Habib argued that the largest estimate of 544 kg is much too high and an upper limit of 200 to 250 kg is more realistic. Witton and Habib considered the methods used by researchers who obtained smaller mass estimates equally flawed. Most have been produced by scaling modern animals such as bats and birds up to Pteranodon size, despite the fact that pterosaurs have vastly different body proportions and soft tissue anatomy from any living animal. Other distinguishing characteristics that set Pteranodon apart from other pterosaurs include narrow neural spines on the vertebrae, plate-like bony ligaments strengthening the vertebrae above the hip, and a relatively short tail in which the last few vertebrae are fused into a long rod. The entire length of the tail was about 3.5% as long as the wingspan, or up to in the largest males. Skull and beak Unlike earlier pterosaurs, such as Rhamphorhynchus and Pterodactylus, Pteranodon had toothless beaks, similar to those of birds. Pteranodon beaks were made of solid, bony margins that projected from the base of the jaws. The beaks were long, slender, and ended in thin, sharp points. The upper jaw, which was longer than the lower jaw, was curved upward; while this normally has been attributed only to the upward-curving beak, one specimen (UALVP 24238) has a curvature corresponding with the beak widening towards the tip. While the tip of the beak is not known in this specimen, the level of curvature suggests it would have been extremely long. The unique form of the beak in this specimen led Alexander Kellner to assign it to a distinct genus, Dawndraco, in 2010. The most distinctive characteristic of Pteranodon is its cranial crest. These crests consisted of skull bones (frontals) projecting upward and backward from the skull. The size and shape of these crests varied due to a number of factors, including age, sex, and species. Male Pteranodon sternbergi, the older species of the two described to date (and sometimes placed in the distinct genus Geosternbergia), had a more vertical crest with a broad forward projection, while their descendants, Pteranodon longiceps, evolved a narrower, more backward-projecting crest. Females of both species were smaller and bore small, rounded crests. The crests were probably mainly display structures, though they may have had other functions as well. Paleobiology Flight The wing shape of Pteranodon suggests that it would have flown rather like a modern-day albatross. This is based on the fact that Pteranodon had a high aspect ratio (wingspan to chord length) similar to that of the albatross — 9:1 for Pteranodon, compared to 8:1 for an albatross. Albatrosses spend long stretches of time at sea fishing, and use a flight pattern called "dynamic soaring" which exploits the vertical gradient of wind speed near the ocean surface to travel long distances without flapping, and without the aid of thermals (which do not occur over the open ocean the same way they do over land). While most of a Pteranodon flight would have depended on soaring, like long-winged seabirds, it probably required an occasional active, rapid burst of flapping, and studies of Pteranodon wing loading (the strength of the wings vs. the weight of the body) indicate that they were capable of substantial flapping flight, contrary to some earlier suggestions that they were so big they could only glide. However, a more recent study suggests that it relied on thermal soaring, unlike modern seabirds but much like modern continental flyers and the extinct Pelagornis. Like other pterosaurs, Pteranodon probably took off from a standing, quadrupedal position. Using their long forelimbs for leverage, they would have vaulted themselves into the air in a rapid leap. Almost all of the energy would have been generated by the forelimbs. The upstroke of the wings would have occurred when the animal cleared the ground followed by a rapid down-stroke to generate additional lift and complete the launch into the air. Terrestrial locomotion Historically, the terrestrial locomotion of Pteranodon, especially whether it was bipedal or quadrupedal, has been the subject of debate. Today, most pterosaur researchers agree that pterosaurs were quadrupedal, thanks largely to the discovery of pterosaur trackways. The possibility of aquatic locomotion via swimming has been discussed briefly in several papers (Bennett 2001, 1994, and Bramwell & Whitfield 1974). Diet The diet of Pteranodon is known to have included fish; fossilized fish bones have been found in the stomach area of one Pteranodon, and a fossilized fish bolus has been found between the jaws of another Pteranodon, specimen AMNH 5098. Numerous other specimens also preserve fragments of fish scales and vertebrae near the torso, indicating that fish made up a majority of the diet of Pteranodon (though they may also have taken invertebrates). Traditionally, most researchers have suggested that Pteranodon would have taken fish by dipping their beaks into the water while in low, soaring flight. However, this was probably based on the assumption that the animals could not take off from the water surface. It is more likely that Pteranodon could take off from the water, and would have dipped for fish while swimming rather than while flying. Even a small, female Pteranodon could have reached a depth of at least with its long bill and neck while floating on the surface, and they may have reached even greater depths by plunge-diving into the water from the air like some modern long-winged seabirds. In 1994, Bennett noted that the head, neck, and shoulders of Pteranodon were as heavily built as diving birds, and suggested that they could dive by folding back their wings like the modern gannet. Crest function Pteranodon was notable for its skull crest, though the function of this crest has been a subject of debate. Most explanations have focused on the blade-like, backward pointed crest of male P. longiceps, however, and ignored the wide range of variation across age and sex. The fact that the crests vary so much rules out most practical functions other than for use in mating displays. Therefore, display was probably the main function of the crest, and any other functions were secondary. Scientific interpretations of the crest's function began in 1910, when George Francis Eaton proposed two possibilities: an aerodynamic counterbalance and a muscle attachment point. He suggested that the crest might have anchored large, long jaw muscles, but admitted that this function alone could not explain the large size of some crests. Bennett (1992) agreed with Eaton's own assessment that the crest was too large and variable to have been a muscle attachment site. Eaton had suggested that a secondary function of the crest might have been as a counterbalance against the long beak, reducing the need for heavy neck muscles to control the orientation of the head. Wind tunnel tests showed that the crest did function as an effective counterbalance to a degree, but Bennett noted that, again, the hypothesis focuses only on the long crests of male P. longiceps, not on the larger crests of P. sternbergi and very small crests that existed among the females. Bennett found that the crests of females had no counterbalancing effect, and that the crests of male P. sternbergi would, by themselves, have a negative effect on the balance of the head. In fact, side to side movement of the crests would have required more, not less, neck musculature to control balance. In 1943, Dominik von Kripp suggested that the crest may have served as a rudder, an idea embraced by several later researchers. One researcher, Ross S. Stein, even suggested that the crest may have supported a membrane of skin connecting the backward-pointing crest to the neck and back, increasing its surface area and effectiveness as a rudder. The rudder hypothesis, again, does not take into account females nor P. sternbergi, which had an upward-pointing, not backward-pointing crest. Bennett also found that, even in its capacity as a rudder, the crest would not provide nearly so much directional force as simply maneuvering the wings. The suggestion that the crest was an air brake, and that the animals would turn their heads to the side in order to slow down, suffers from a similar problem. Additionally, the rudder and air brake hypotheses do not explain why such large variation exists in crest size even among adults. Alexander Kellner suggested that the large crests of the pterosaur Tapejara, as well as other species, might be used for heat exchange, allowing these pterosaurs to absorb or shed heat and regulate body temperature, which also would account for the correlation between crest size and body size. There is no evidence of extra blood vessels in the crest for this purpose, however, and the large, membranous wings filled with blood vessels would have served that purpose much more effectively. With these hypotheses ruled out, the best-supported hypothesis for crest function seems to be as a sexual display. This is consistent with the size variation seen in fossil specimens, where females and juveniles have small crests and males large, elaborate, variable crests. Sexual variation Adult Pteranodon specimens may be divided into two distinct size classes, small and large, with the large size class being about one and a half times larger than the small class, and the small class being twice as common as the large class. Both size classes lived alongside each other, and while researchers had previously suggested that they represent different species, Christopher Bennett showed that the differences between them are consistent with the concept that they represent females and males, and that Pteranodon species were sexually dimorphic. Skulls from the larger size class preserve large, upward and backward pointing crests, while the crests of the smaller size class are small and triangular. Some larger skulls also show evidence of a second crest that extended long and low, toward the tip of the beak, which is not seen in smaller specimens. The sex of the different size classes was determined, not from the skulls, but from the pelvic bones. Contrary to what may be expected, the smaller size class had disproportionately large and wide-set pelvic bones. Bennett interpreted this as indicating a more spacious birth canal, through which eggs would pass. He concluded that the small size class with small, triangular crests represent females, and the larger, large-crested specimens represent males. Note that the overall size and crest size also corresponds to age. Immature specimens are known from both females and males, and immature males often have small crests similar to adult females. Therefore, it seems that the large crests only developed in males when they reached their large, adult size, making the sex of immature specimens difficult to establish from partial remains. The fact that females appear to have outnumbered males two to one suggests that, as with modern animals with size-related sexual dimorphism, such as sea lions and other pinnipeds, Pteranodon might have been polygynous, with a few males competing for association	specimens of Pteranodon have been found than any other pterosaur, with about 1,200 specimens known to science, many of them well preserved with nearly complete skulls and articulated skeletons. It was an important part of the animal community in the Western Interior Seaway. Pteranodon was a pterosaur, meaning that it is not a dinosaur. By definition, all dinosaurs belong to one of the two groups within Dinosauria, i.e. Saurischia or Ornithischia. As such, this excludes pterosaurs. Nonetheless, Pteranodon is frequently featured in dinosaur media and is strongly associated with dinosaurs by the general public. While not dinosaurs, pterosaurs such as Pteranodon form a clade closely related to dinosaurs as both fall within the clade Avemetatarsalia. Discovery and history First fossils Pteranodon was the first pterosaur found outside of Europe. Its fossils first were found by Othniel Charles Marsh in 1871, in the Late Cretaceous Smoky Hill Chalk deposits of western Kansas. These chalk beds were deposited at the bottom of what was once the Western Interior Seaway, a large shallow sea over what now is the midsection of the North American continent. These first specimens, YPM 1160 and YPM 1161, consisted of partial wing bones, as well as a tooth from the prehistoric fish Xiphactinus, which Marsh mistakenly believed to belong to this new pterosaur (all known pterosaurs up to that point had teeth). In 1871, Marsh named the find Pterodactylus oweni, assigning it to the well-known (but much smaller) European genus Pterodactylus. Marsh also collected more wing bones of the large pterosaur in 1871. Realizing that the name he had chosen had already been used for Harry Seeley's European pterosaur species Pterodactylus oweni in 1864, Marsh renamed his giant North American pterosaur Pterodactylus occidentalis, meaning "Western wing finger," in his 1872 description of the new specimen. He named two additional species, based on size differences: Pterodactylus ingens (the largest specimen so far), and Pterodactylus velox (the smallest). Meanwhile, Marsh's rival Edward Drinker Cope had unearthed several specimens of the large North American pterosaur. Based on these specimens, Cope named two new species, Ornithochirus umbrosus and Ornithochirus harpyia, in an attempt to assign them to the large European genus Ornithocheirus, though he misspelled the name (forgetting the 'e'). Cope's paper naming his species was published in 1872, just five days after Marsh's paper. This resulted in a dispute, fought in the published literature, over whose names had priority in what obviously were the same species. Cope conceded in 1875 that Marsh's names did have priority over his, but maintained that Pterodactylus umbrosus was a distinct species (but not genus) from any that Marsh had named previously. Re-evaluation by later scientists has supported Marsh's case, refuting Cope's assertion that P. umbrosus represented a larger, distinct species. A toothless pterosaur While the first Pteranodon wing bones were collected by Marsh and Cope in the early 1870s, the first Pteranodon skull was found on May 2, 1876, along the Smoky Hill River in Wallace County (now Logan County), Kansas, USA, by Samuel Wendell Williston, a fossil collector working for Marsh. A second, smaller skull soon was discovered as well. These skulls showed that the North American pterosaurs were different from any European species, in that they lacked teeth and had bony crests on their skulls. Marsh recognized this major difference, describing the specimens as "distinguished from all previously known genera of the order Pterosauria by the entire absence of teeth." Marsh recognized that this characteristic warranted a new genus, and he coined the name Pteranodon ("wing without tooth") in 1876. Marsh reclassified all the previously named North American species from Pterodactylus to Pteranodon. He considered the smaller skull to belong to Pteranodon occidentalis, based on its size. Marsh classified the larger skull, YPM 1117, in the new species Pteranodon longiceps, which he thought to be a medium-sized species in between the small P. occidentalis and the large P. ingens. Marsh also named several additional species: Pteranodon comptus and Pteranodon nanus were named for fragmentary skeletons of small individuals, while Pteranodon gracilis was based on a wing bone that he mistook for a pelvic bone. He soon realized his mistake, and re-classified that specimen again into a separate genus, which he named Nyctosaurus. P. nanus was also later recognized as a Nyctosaurus specimen. In 1892, Samuel Williston examined the question of Pteranodon classification. He noticed that, in 1871, Seeley had mentioned the existence of a partial set of toothless pterosaur jaws from the Cambridge Greensand of England, which he named Ornithostoma. Because the primary characteristic Marsh had used to separate Pteranodon from other pterosaurs was its lack of teeth, Williston concluded that "Ornithostoma" must be considered the senior synonym of Pteranodon. However, in 1901, Pleininger pointed out that "Ornithostoma" had never been scientifically described or even assigned a species name until Williston's work, and therefore had been a nomen nudum and could not beat out Pteranodon for naming priority. Williston accepted this conclusion and went back to calling the genus Pteranodon. However, both Williston and Pleininger were incorrect, because unnoticed by both of them was the fact that, in 1891, Seeley himself had finally described and properly named Ornithostoma, assigning it to the species O. sedgwicki. In the 2010s, more research on the identity of Ornithostoma showed that it was probably not Pteranodon or even a close relative, but may in fact have been an azhdarchoid, a different type of toothless pterosaur. Revising species Williston was also the first scientist to critically evaluate all of the pteranodon species classified by Cope and Marsh. He agreed with most of Marsh's classification, with a few exceptions. First, he did not believe that P. ingens and P. umbrosus could be considered synonyms, which even Cope had come to believe. He considered both P. velox and P. longiceps to be dubious; the first was based on non-diagnostic fragments, and the second, though known from a complete skull, probably belonged to one of the other, previously-named species. In 1903, Williston revisited the question of Pteranodon classification, and revised his earlier conclusion that there were seven species down to just three. He considered both P. comptus and P. nanus to be specimens of Nyctosaurus, and divided the others into small (P. velox), medium (P. occidentalis), and large species (P. ingens), based primarily on the shape of their upper arm bones. He thought P. longiceps, the only one known from a skull, could be a synonym of either P. velox or P. occidentalis, based on its size. In 1910, Eaton became the first scientist to publish a more detailed description of the entire Pteranodon skeleton, as it was known at the time. He used his findings to revise the classification of the genus once again based on a better understanding of the differences in pteranodont anatomy. Eaton conducted experiments using clay models of bones to help determine the effects of crushing and flattening on the shapes of the arm bones Williston had used in his own classification. Eaton found that most of the differences in bone shapes could be easily explained by the pressures of fossilization, and concluded that no Pteranodon skeletons had any significant differences from each other besides their size. Therefore, Eaton was left to decide his classification scheme based on differences in the skulls alone, which he assigned to species just as Marsh did, by their size. In the end, Eaton recognized only three valid species: P. occidentalis, P. ingens, and P. longiceps. The discovery of specimens with upright crests, classified by Harksen in 1966 as the new species Pteranodon sternbergi, complicated the situation even further, prompting another revision of the genus by Miller in 1972. Because it was impossible to determine crest shape for all of the species based on headless skeletons, Miller concluded that all Pteranodon species except the two based on skulls (P. longiceps and P. sternbergi) must be considered nomena dubia and abandoned. The skull Eaton thought belonged to P. ingens was placed in the new species Pteranodon marshi, and the skull Eaton assigned to P. occidentalis was re-named Pteranodon eatoni. Miller also recognized another species based on a skull with a crest similar to that of P. sternbergi; Miller named this Pteranodon walkeri. To help bring order to this tangle of names, Miller created three categories or "subgenera" for them. P. marshi and P. longiceps were placed in the subgenus Longicepia, though this was later changed to simply Pteranodon due to the rules of priority. P. sternbergi and P. walkeri, the upright-crested species, were given the subgenus Sternbergia, which was later changed to Geosternbergia because Sternbergia was already in use ("preoccupied"). Finally, Miller named the subgenus Occidentalia for P. eatoni, the skull formerly associated with P. occidentalis. Miller further expanded the concept of Pteranodon to include Nyctosaurus as a fourth subgenus. Miller considered these to be an evolutionary progression, with the primitive Nyctosaurus, at the time thought to be crestless, giving rise to Occidentalia (with a small crest), which in turn gave rise to Pteranodon with its long backwards crest, finally leading to Geosternbergia with its large, upright crest. However, Miller made several mistakes in his study concerning which specimens Marsh had assigned to which species, and most scientists disregarded his work on the subject in their later research, though Wellnhofer (1978) followed Miller's species list. and Schoch (1984) somewhat oddly published another revision that essentially returned to Marsh's original classification scheme, most notably sinking P. longiceps as a synonym of P. ingens. Recognizing variation During the early 1990s, S. Christopher Bennett also published several major papers reviewing the anatomy, taxonomy and life history of Pteranodon. Fragmentary fossils assigned to Pteranodon have also been discovered in Skåne, Sweden. Description Pteranodon species are extremely well represented in the fossil record, allowing for detailed descriptions of their anatomy and analysis of their life history. Over 1,000 specimens have been identified, though less than half are complete enough to give researchers good anatomical information. Still, this is more fossils material than is known for any other pterosaur, and it includes both male and female specimens of various age groups and possibly species. Adult Pteranodon specimens from the two major species can be divided into two distinct size classes. The smaller class of specimens have small, rounded head crests and very wide pelvic canals, even wider than those of the much larger size class. The size of the pelvic canal probably allowed the laying of eggs, indicating that these smaller adults are females. The larger size class, representing male individuals, have narrow hips and very large crests, which were probably for display. Adult male Pteranodon were among the largest pterosaurs, and were the largest flying animals known until the late 20th century, when the giant azhdarchid pterosaurs were discovered. The wingspan of an average adult male Pteranodon was . Adult females were much smaller, averaging in wingspan. The largest specimen of Pteranodon longiceps from the Niobrara Formation measured from wingtip to wingtip. An even larger specimen is known from the Pierre Shale Formation, with a wingspan of , though this specimen may belong to the distinct genus and species Geosternbergia maysei. While most specimens are found crushed, enough fossils exist to put together a detailed description of the animal. Methods used to estimate the mass of large male Pteranodon specimens (those with wingspans of about 7 meters) have been notoriously unreliable, producing a wide range of estimates. In a review of pterosaur size estimates published in 2010, researchers Mark Witton and Mike Habib argued that the largest estimate of 544 kg is much too high and an upper limit of 200 to 250 kg is more realistic. Witton and Habib considered the methods used by researchers who obtained smaller mass estimates equally flawed. Most have been produced by scaling modern animals such as bats and birds up to Pteranodon size, despite the fact that pterosaurs have vastly different body proportions and soft tissue anatomy from any living animal. Other distinguishing characteristics that set Pteranodon apart from other pterosaurs include narrow neural spines on the vertebrae, plate-like bony ligaments strengthening the vertebrae above the hip, and a relatively short tail in which the last few vertebrae are fused into a long rod. The entire length of the tail was about 3.5% as long as the wingspan, or up to in the largest males. Skull and beak Unlike earlier pterosaurs, such as Rhamphorhynchus and Pterodactylus, Pteranodon had toothless beaks, similar to those of birds. Pteranodon beaks were made of solid, bony margins that projected from the base of the jaws. The beaks were long, slender, and ended in thin, sharp points. The upper jaw, which was longer than the lower jaw, was curved upward; while this normally has been attributed only to the upward-curving beak, one specimen (UALVP 24238) has a curvature corresponding with the beak widening towards the tip. While the tip of the beak is not known in this specimen, the level of curvature suggests it would have been extremely long. The unique form of the beak in this specimen led Alexander Kellner to assign it to a distinct genus, Dawndraco, in 2010. The most distinctive characteristic of Pteranodon is its cranial crest. These crests consisted of skull bones (frontals) projecting upward and backward from the skull. The size and shape of these crests varied due to a number of factors, including age, sex, and species. Male Pteranodon sternbergi, the older species of the two described to date (and sometimes placed in the distinct genus Geosternbergia), had a more vertical crest with a broad forward projection, while their descendants, Pteranodon longiceps, evolved a narrower, more backward-projecting crest. Females of both species were smaller and bore small, rounded crests. The crests were probably mainly display structures, though they may have had other functions as well. Paleobiology Flight The wing shape of Pteranodon suggests that it would have flown rather like a modern-day albatross. This is based on the fact that Pteranodon had a high aspect ratio (wingspan to chord length) similar to that of the albatross — 9:1 for Pteranodon, compared to 8:1 for an albatross. Albatrosses spend long stretches of time at sea fishing, and
like some other languages, uses a periphrastic passive. Rather than conjugating directly for voice, English uses the past participle form of the verb plus an auxiliary verb, either be or get (called linking verbs in traditional grammar), to indicate passive voice. The money was donated to the school. The vase got broken during the fight. All men are created equal. If the agent is mentioned, it usually appears in a prepositional phrase introduced by the preposition by. Without agent: The paper was marked. With agent: The paper was marked by Mr. Tan. The subject of the passive voice usually corresponds to the direct object of the corresponding active-voice formulation (as in the above examples), but English also allows passive constructions in which the subject corresponds to an indirect object or preposition complement: We were given tickets. (subject we corresponds to the indirect object of give) Tim was operated on yesterday. (subject Tim corresponds to the complement of the preposition on) In sentences of the second type, a stranded preposition is left. This is called the prepositional passive or pseudo-passive (although the latter term can also be used with other meanings). The active voice is the dominant voice used in English. Many commentators, notably George Orwell in his essay "Politics and the English Language" and Strunk & White in The Elements of Style, have urged minimizing use of the passive voice, but this is almost always based on these commentators' misunderstanding of what the passive voice is. Contrary to common critiques, the passive voice has important uses, with virtually all writers using the passive voice (including Orwell and Strunk & White). There is general agreement that the passive voice is useful for emphasis, or when the receiver of the action is more important than the actor. Merriam–Webster's Dictionary of English Usage refers to three statistical studies of passive versus active sentences in various periodicals, stating: "the highest incidence of passive constructions was 13 percent. Orwell runs to a little over 20 percent in "Politics and the English Language". Clearly he found the construction useful in spite of his advice to avoid it as much as possible". Defining "passive" In the field of linguistics, the term passive is applied to a wide range of grammatical structures. Linguists therefore find it difficult to define the term in a way that makes sense across all human languages. The canonical passive in European languages has the following properties: The subject is not an agent. There is a change in: word order; or in nominal morphology—the form of the nouns in the sentence. There is specific verbal morphology—a particular form of the verb indicates passive voice. The problem arises with non-European languages. Many constructions in these languages share at least one property with the canonical European passive, but not all. While it seems justified to call these constructions passive when comparing them to European languages' passive constructions, as a whole the passives of the world's languages do not share a single common feature. R. M. W. Dixon has defined four criteria for determining whether a construction is a passive: It applies to underlying transitive clauses and forms a	advice to avoid it as much as possible". Defining "passive" In the field of linguistics, the term passive is applied to a wide range of grammatical structures. Linguists therefore find it difficult to define the term in a way that makes sense across all human languages. The canonical passive in European languages has the following properties: The subject is not an agent. There is a change in: word order; or in nominal morphology—the form of the nouns in the sentence. There is specific verbal morphology—a particular form of the verb indicates passive voice. The problem arises with non-European languages. Many constructions in these languages share at least one property with the canonical European passive, but not all. While it seems justified to call these constructions passive when comparing them to European languages' passive constructions, as a whole the passives of the world's languages do not share a single common feature. R. M. W. Dixon has defined four criteria for determining whether a construction is a passive: It applies to underlying transitive clauses and forms a derived intransitive. The entity that is the patient or the object of the transitive verb in the underlying representation (indicated as O in linguistic terminology) becomes the core argument of the clause (indicated as S, since the core argument is the subject of an intransitive). The agent in the underlying representation (indicated as A) becomes a chômeur, a noun in the periphery that is not a core argument. It is marked by a non-core case or becomes part of an adpositional phrase, etc. This can be omitted, but there is always the option of including it. There is some explicit marking of the construction. Dixon acknowledges that this excludes some constructions labeled as passive by some linguists. Adversative passive In some languages, including several Southeast Asian languages, the passive voice is sometimes used to indicate that an action or event was unpleasant or undesirable. This so-called adversative passive works like the ordinary passive voice in terms of syntactic structure—that is, a theme or instrument acts as subject. In addition, the construction indicates adversative affect, suggesting that someone was negatively affected. In Japanese, for example, the adversative passive (also called indirect passive) indicates adversative affect. The indirect or adversative passive has the same form as the direct passive. Unlike the direct passive, the indirect passive may be used with intransitive verbs. Yup'ik, from the Eskimo–Aleut family, has two different suffixes that can indicate passive, -cir- and -ma-. The morpheme -cir- has an adversative meaning. If an agent is included in a passive sentence with the -cir passive, the noun is usually in the allative (oblique) case. Stative and dynamic passive In some languages, for example English, there is often a similarity between clauses expressing an action or event in the passive voice and clauses expressing a state. For example, the string of words "The dog is fed" can have the following two different meanings: The dog is fed (twice a day). The dog is fed (so we can leave now). The additions in parentheses "force" the same string of words to clearly show only one of their two possible grammatical functions and the related meaning. In the first sentence, the combination of the auxiliary verb "is" and the past participle "fed" is a regular example of the construction of the passive voice in English. In the second sentence, "is" can however be interpreted as an ordinary copula and the past participle as an adjective. Sentences of the second type are called false passives by some linguists, who feel that such sentences are simply confused with the passive voice due to their outward similarity. Other linguists consider the second type to be a different kind of passive – a stative passive (rarely called statal, static, or resultative passive), in contrast to the dynamic or eventive passive illustrated by the first sentence. Some languages express or can express these different meanings using different constructions. The difference between dynamic and stative passives is more evident in languages such as German that use different words or constructions for the two. In German, the auxiliary verb marks static passive (German: , rarely , in referring to German also called or ), while marks the dynamic passive ( or , rarely , in referring to German also called or or simply or ). The English string of words "the lawn is mown" has two possible meanings corresponding
are primitive recursive in Q and R: NOT_Q(x) . Q OR R: Q(x) V R(x), Q AND R: Q(x) & R(x), Q IMPLIES R: Q(x) → R(x) Q is equivalent to R: Q(x) ≡ R(x) #E: The following predicates are primitive recursive in the predicate R: (Ey)y<z R(x, y) where (Ey)y<z denotes "there exists at least one y that is less than z such that" (y)y<z R(x, y) where (y)y<z denotes "for all y less than z it is true that" μyy<z R(x, y). The operator μyy<z R(x, y) is a bounded form of the so-called minimization- or mu-operator: Defined as "the least value of y less than z such that R(x, y) is true; or z if there is no such value." #F: Definition by cases: The function defined thus, where Q1, ..., Qm are mutually exclusive predicates (or "ψ(x) shall have the value given by the first clause that applies), is primitive recursive in φ1, ..., Q1, ... Qm: φ(x) = φ1(x) if Q1(x) is true, . . . . . . . . . . . . . . . . . . . φm(x) if Qm(x) is true φm+1(x) otherwise #G: If φ satisfies the equation: φ(y,x) = χ(y, COURSE-φ(y; x2, ... xn ), x2, ... xn then φ is primitive recursive in χ. The value COURSE-φ(y; x2 to n ) of the course-of-values function encodes the sequence of values φ(0,x2 to n), ..., φ(y-1,x2 to n) of the original function. Use in first-order Peano arithmetic In first-order Peano arithmetic, there are infinitely many variables (0-ary symbols) but no k-ary non-logical symbols with k>0 other than S, +, *, and ≤. Thus in order to define primitive recursive functions one has to use the following trick by Gödel. By using a Gödel numbering for sequences, for example Gödel's β function, any finite sequence of numbers can be encoded by a single number. Such a number can therefore represent the primitive recursive function until a given n. Let h be a 1-ary primitive recursion function defined by: where C is a constant and g is an already defined function. Using Gödel's β function, for any sequence of natural numbers (k0, k1, ..., kn), there are natural numbers b and c such that, for every i ≤ n, β(b, c, i) = ki. We may thus use the following formula to define h; more precisely, m=h(n) is a shorthand for the following: and the equating to g, being already defined, is in fact shorthand for some other already defined formula (as is β, whose formula is given here). The generalization to any k-ary primitive recursion function is trivial. Relationship to recursive functions The broader class of partial recursive functions is defined by introducing an unbounded search operator. The use of this operator may result in a partial function, that is, a relation with at most one value for each argument, but does not necessarily have any value for any argument (see domain). An equivalent definition states that a partial recursive function is one that can be computed by a Turing machine. A total recursive function is a partial recursive function that is defined for every input. Every primitive recursive function is total recursive, but not all total recursive functions are primitive recursive. The Ackermann function A(m,n) is a well-known example of a total recursive function (in fact, provable total), that is not primitive recursive. There is a characterization of the primitive recursive functions as a subset of the total recursive functions using the Ackermann function. This characterization states that a function is primitive recursive if and only if there is a natural number m such that the function can be computed by a Turing machine that always halts within A(m,n) or fewer steps, where n is the sum of the arguments of the primitive recursive function. An important property of the primitive recursive functions is that they are a recursively enumerable subset of the set of all total recursive functions (which is not itself recursively enumerable). This means that there is a single computable function f(m,n) that enumerates the primitive recursive functions, namely: For every primitive recursive function g, there is an m such that g(n) = f(m,n) for all n, and For every m, the function h(n) = f(m,n) is primitive recursive.f can be explicitly constructed by iteratively repeating all possible ways of creating primitive recursive functions. Thus, it is provably total. One can use a diagonalization argument to show that f is not recursive primitive in itself: had it been such, so would be h(n) = f(n,n)+1. But if this equals some primitive recursive function, there is an m such that h(n) = f(m,n) for all n, and then h(m) = f(m,m), leading to contradiction. However, the set of primitive recursive functions is not the largest recursively enumerable subset of the set of all total recursive functions. For example, the set of provably total functions (in Peano arithmetic) is also recursively enumerable, as one can enumerate all the proofs of the theory. While all primitive recursive functions are provably total, the converse is not true. Limitations Primitive recursive functions tend to correspond very closely with our intuition of what a computable function must be. Certainly the initial functions are intuitively computable (in their very simplicity), and the two operations by which one can create new primitive recursive functions are also very straightforward. However, the set of primitive recursive functions does not include every possible total computable function—this can be seen with a variant of Cantor's diagonal argument. This argument provides a total computable function that is not primitive recursive. A sketch of the proof is as follows: This argument can be applied to any class of computable (total) functions that can be enumerated in this way, as explained in the article Machine that always halts. Note however that the partial computable functions (those that need not be defined for all arguments) can be explicitly enumerated, for instance by enumerating Turing machine encodings. Other examples of total recursive but not primitive recursive functions are known: The function that takes m to Ackermann(m,m) is a unary total recursive function that is not primitive recursive. The Paris–Harrington theorem involves a total recursive function that is not primitive recursive. The Sudan function The Goodstein function Variants Constant functions Instead of , alternative definitions use just one 0-ary zero function as a primitive function that always returns zero, and built the constant functions from the zero function, the successor function and the composition operator. Weak primitive recursion The 1-place predecessor function is primitive recursive, see section #Predecessor. Fischer, Fischer & Beigel removed the implicit predecessor from the recursion rule, replacing it by the weaker rule They proved that the predecessor function still could be defined, and hence that "weak" primitive recursion also defines the primitive recursive functions. Iterative functions Weakening this even further by using functions of arity k+1, removing and from the arguments of completely, we get the iteration rule: The class of iterative functions is defined the same way as the class of primitive recursive functions except with this weaker rule. These are conjectured to be a proper subset of the primitive recursive functions. Additional primitive recursive forms Some additional forms of recursion also define functions that are in fact primitive recursive. Definitions in these forms may be easier to find or more natural for reading or writing. Course-of-values recursion defines primitive recursive functions. Some forms of mutual recursion also define primitive recursive functions. The functions that can be programmed in the LOOP programming language are exactly the primitive recursive functions. This gives a different characterization of the power of these functions. The main limitation of the LOOP language, compared to a Turing-complete language, is that in the LOOP language the number of times that each loop will run is specified before the loop begins to run. Computer language definition An example of a primitive recursive programming language is one that contains basic arithmetic operators (e.g. + and −, or ADD and SUBTRACT), conditionals	& NOT(pix'\|a) lh(a): the "length" or number of non-vanishing exponents in a lo(a, b): (logarithm of a to base b): If a, b > 1 then the greatest x such that bx \| a else 0 In the following, the abbreviation x =def x1, ... xn; subscripts may be applied if the meaning requires. #A: A function φ definable explicitly from functions Ψ and constants q1, ... qn is primitive recursive in Ψ. #B: The finite sum Σy<z ψ(x, y) and product Πy<zψ(x, y) are primitive recursive in ψ. #C: A predicate P obtained by substituting functions χ1,..., χm for the respective variables of a predicate Q is primitive recursive in χ1,..., χm, Q. #D: The following predicates are primitive recursive in Q and R: NOT_Q(x) . Q OR R: Q(x) V R(x), Q AND R: Q(x) & R(x), Q IMPLIES R: Q(x) → R(x) Q is equivalent to R: Q(x) ≡ R(x) #E: The following predicates are primitive recursive in the predicate R: (Ey)y<z R(x, y) where (Ey)y<z denotes "there exists at least one y that is less than z such that" (y)y<z R(x, y) where (y)y<z denotes "for all y less than z it is true that" μyy<z R(x, y). The operator μyy<z R(x, y) is a bounded form of the so-called minimization- or mu-operator: Defined as "the least value of y less than z such that R(x, y) is true; or z if there is no such value." #F: Definition by cases: The function defined thus, where Q1, ..., Qm are mutually exclusive predicates (or "ψ(x) shall have the value given by the first clause that applies), is primitive recursive in φ1, ..., Q1, ... Qm: φ(x) = φ1(x) if Q1(x) is true, . . . . . . . . . . . . . . . . . . . φm(x) if Qm(x) is true φm+1(x) otherwise #G: If φ satisfies the equation: φ(y,x) = χ(y, COURSE-φ(y; x2, ... xn ), x2, ... xn then φ is primitive recursive in χ. The value COURSE-φ(y; x2 to n ) of the course-of-values function encodes the sequence of values φ(0,x2 to n), ..., φ(y-1,x2 to n) of the original function. Use in first-order Peano arithmetic In first-order Peano arithmetic, there are infinitely many variables (0-ary symbols) but no k-ary non-logical symbols with k>0 other than S, +, *, and ≤. Thus in order to define primitive recursive functions one has to use the following trick by Gödel. By using a Gödel numbering for sequences, for example Gödel's β function, any finite sequence of numbers can be encoded by a single number. Such a number can therefore represent the primitive recursive function until a given n. Let h be a 1-ary primitive recursion function defined by: where C is a constant and g is an already defined function. Using Gödel's β function, for any sequence of natural numbers (k0, k1, ..., kn), there are natural numbers b and c such that, for every i ≤ n, β(b, c, i) = ki. We may thus use the following formula to define h; more precisely, m=h(n) is a shorthand for the following: and the equating to g, being already defined, is in fact shorthand for some other already defined formula (as is β, whose formula is given here). The generalization to any k-ary primitive recursion function is trivial. Relationship to recursive functions The broader class of partial recursive functions is defined by introducing an unbounded search operator. The use of this operator may result in a partial function, that is, a relation with at most one value for each argument, but does not necessarily have any value for any argument (see domain). An equivalent definition states that a partial recursive function is one that can be computed by a Turing machine. A total recursive function is a partial recursive function that is defined for every input. Every primitive recursive function is total recursive, but not all total recursive functions are primitive recursive. The Ackermann function A(m,n) is a well-known example of a total recursive function (in fact, provable total), that is not primitive recursive. There is a characterization of the primitive recursive functions as a subset of the total recursive functions using the Ackermann function. This characterization states that a function is primitive recursive if and only if there is a natural number m such that the function can be computed by a Turing machine that always halts within A(m,n) or fewer steps, where n is the sum of the arguments of the primitive recursive function. An important property of the primitive recursive functions is that they are a recursively enumerable subset of the set of all total recursive functions (which is not itself recursively enumerable). This means that there is a single computable function f(m,n) that enumerates the primitive recursive functions, namely: For every primitive recursive function g, there is an m such that g(n) = f(m,n) for all n, and For every m, the function h(n) = f(m,n) is primitive recursive.f can be explicitly constructed by iteratively repeating all possible ways of creating primitive recursive functions. Thus, it is provably total. One can use a diagonalization argument to show that f is not recursive primitive in itself: had it been such, so would be h(n) = f(n,n)+1. But if this equals some primitive recursive function, there is an m such that h(n) = f(m,n) for all n, and then h(m) = f(m,m), leading to contradiction. However, the set of primitive recursive functions is not the largest recursively enumerable subset of the set of all total recursive functions. For example, the set of provably total functions (in Peano arithmetic) is also recursively enumerable, as one can enumerate all the proofs of the theory. While all primitive recursive functions are provably total, the converse is not true. Limitations Primitive recursive functions tend to correspond very closely with our intuition of what a computable function must be. Certainly the initial functions are intuitively computable (in their very simplicity), and the two operations by which one can create new primitive recursive functions are also very straightforward. However, the set of primitive recursive functions does not include every possible total computable function—this can be seen with a variant of Cantor's diagonal argument. This argument provides a total computable function that is not primitive recursive. A sketch of the proof is as follows: This argument can be applied to any class of computable (total) functions that can be enumerated in this way, as explained in the article Machine that always halts. Note however that the partial computable functions (those that need not be defined for all arguments) can be explicitly enumerated, for instance by enumerating Turing machine encodings. Other examples of total recursive but not primitive recursive functions are known: The function that takes m to Ackermann(m,m) is a unary total recursive function that is not primitive recursive. The Paris–Harrington theorem involves a total recursive function that is not primitive recursive. The Sudan function The Goodstein function Variants Constant functions Instead of , alternative definitions use just one 0-ary zero function as a primitive function that always returns zero, and built the constant functions from the zero function, the successor function and the composition operator. Weak primitive recursion The 1-place predecessor function is primitive recursive, see section #Predecessor. Fischer, Fischer & Beigel removed the implicit predecessor from the recursion rule, replacing it by the weaker rule They proved that the predecessor function still could be defined, and hence that "weak" primitive recursion also defines the primitive recursive functions. Iterative functions Weakening this even further by using functions of arity k+1, removing and from the arguments of completely, we get the iteration rule: The class of iterative functions is defined the same way as the class of primitive recursive functions except with this weaker rule. These are conjectured to be a proper subset of the primitive recursive functions. Additional primitive recursive forms Some additional forms of recursion also define functions that are in fact primitive recursive. Definitions in these forms may be easier to find or more natural for reading or writing. Course-of-values recursion defines primitive recursive functions. Some forms of mutual recursion also define primitive recursive functions. The functions that can be programmed in the LOOP programming language are exactly the primitive recursive functions. This gives a different characterization of the power of these functions. The main limitation of the LOOP language, compared to a Turing-complete language, is that in the LOOP language the number of times that each loop will run is specified before the loop begins to run. Computer language definition An example of a primitive recursive programming language is one that contains basic arithmetic operators (e.g. + and −, or ADD and SUBTRACT), conditionals and comparison (IF-THEN, EQUALS, LESS-THAN), and bounded loops, such as the basic for loop, where there is a known or calculable upper bound to all loops (FOR i FROM 1 TO n, with neither i nor n modifiable by the loop body). No control structures of greater generality, such as while loops or IF-THEN plus GOTO, are admitted in a primitive recursive language. The LOOP language, introduced in a 1967 paper by Albert R. Meyer and Dennis M. Ritchie, is such a language. Its computing power coincides with the primitive recursive functions. A variant of the LOOP language is Douglas Hofstadter's BlooP in Gödel, Escher, Bach. Adding unbounded loops (WHILE, GOTO) makes the language general recursive and Turing-complete, as are all real-world computer programming languages. The definition of primitive recursive functions implies that their computation halts on every input (after a finite number of steps). On the other hand, the halting problem is undecidable for general recursive functions, even if they are total.
Nestor who appears in The Odyssey Peisistratos of Lapithos, 4th century BC Peisistratus of Orchomenus, king of Arcadian Orchomenus during the Peloponnesian War Pisistratus the Younger,	refer to: Peisistratus (Odyssey), son of Nestor who appears in The Odyssey Peisistratos of Lapithos, 4th century BC Peisistratus of Orchomenus,
authority. Insignia Official office and residence Located near the Diet building, the Office of the Prime Minister of Japan is called the . The original Kantei served from 1929 until 2002, when a new building was inaugurated to serve as the current Kantei. The old Kantei was then converted into the Official Residence, or . The Kōtei lies to the southwest of the Kantei, and is linked by a walkway. Travel The Prime Minister of Japan travels in a Toyota Century, which replaced the Lexus LS 600h L in 2019. For overseas air travel, the Japanese government maintains two Boeing 777, which replaced the Boeing 747-400 also in 2019. The aircraft is also used by the emperor, the members of the Imperial family, and other high-ranking officials. They have the radio callsigns Japanese Air Force One and Japanese Air Force Two when operating on official business, and Cygnus One and Cygnus Two when operating outside of official business (e.g., on training flights). The aircraft always fly together on government missions, with one serving as the primary transport and the other serving as a backup with maintenance personnel on board. The aircraft are officially referred to as . Honours and emoluments Until the mid-1930s, the prime minister of Japan was normally granted a hereditary peerage (kazoku) prior to leaving office if he had not already been ennobled. Titles were usually bestowed in the ranks of count, viscount or baron, depending on the relative accomplishments and status of the prime minister. The two highest ranks, marquess and prince, were only bestowed upon highly distinguished statesmen, and were not granted to a prime minister after 1928. The last prime minister who was a peer was Baron Kijūrō Shidehara, who served as Prime Minister from October 1945 to May 1946. The peerage was abolished when the Constitution of Japan came into effect in May 1947. Certain eminent prime ministers have been awarded the Order of the Chrysanthemum, typically in the degree of Grand Cordon. The highest honour in the Japanese honours system, the Collar of the Order of the Chrysanthemum, has only been conferred upon select prime ministers and eminent statesmen; the last such award to a living prime minister was to Saionji Kinmochi in 1928. More often, the Order of the Chrysanthemum has been a posthumous distinction; the Collar of the order was last awarded posthumously to former prime	appointed by the emperor of Japan after being designated by the National Diet and must enjoy the confidence of the House of Representatives to remain in office. He is the head of the Cabinet and appoints and dismisses the other ministers of state. The literal translation of the Japanese name for the office is Minister for the Comprehensive Administration of (or the Presidency over) the Cabinet. The current prime minister of Japan is Fumio Kishida, who replaced Yoshihide Suga on 4 October 2021. History Before the adoption of the Meiji Constitution, Japan had in practice no written constitution. Originally, a Chinese-inspired legal system known as ritsuryō was enacted in the late Asuka period and early Nara period. It described a government based on an elaborate and rational meritocratic bureaucracy, serving, in theory, under the ultimate authority of the emperor; although in practice, real power was often held elsewhere, such as in the hands of the Fujiwara clan, who intermarried with the imperial family in the Heian period, or by the ruling shōgun. Theoretically, the last ritsuryō code, the Yōrō Code enacted in 752, was still in force at the time of the Meiji Restoration. Under this system, the was the head of the Daijō-kan (Department of State), the highest organ of Japan's pre-modern Imperial government during the Heian period and until briefly under the Meiji Constitution with the appointment of Sanjō Sanetomi in 1871. The office was replaced in 1885 with the appointment of Itō Hirobumi to the new position of Minister President of State, four years before the enactment of the Meiji Constitution, which mentions neither the Cabinet nor the position of Prime Minister explicitly. It took its current form with the adoption of the Constitution of Japan in 1947. To date, 64 people have served this position. The longest serving prime minister to date is Shinzō Abe, who served as prime minister in two terms: from 26 September 2006 until 26 September 2007, and from 26 December 2012 until 16 September 2020. Appointment The prime minister is designated by both houses of the Diet, before the conduct of any other business. For that purpose, each conducts a ballot under the run-off system. If the two houses choose different individuals, then a joint committee of both houses is appointed to agree on a common candidate. Ultimately, however, if the two houses do not agree within ten days, the decision of the House of Representatives is deemed to be that of the Diet. Therefore, the House of Representatives can theoretically ensure the appointment of any prime minister it wants. The candidate is then presented with his or her commission, and formally
recognition particle (SRP) recognizes an N-terminal signal peptide of the nascent protein. Binding of the SRP temporarily pauses synthesis while the ribosome-protein complex is transferred to an SRP receptor on the ER in eukaryotes, and the plasma membrane in prokaryotes. There, the nascent protein is inserted into the translocon, a membrane-bound protein conducting channel composed of the Sec61 translocation complex in eukaryotes, and the homologous SecYEG complex in prokaryotes. In secretory proteins and type I transmembrane proteins, the signal sequence is immediately cleaved from the nascent polypeptide once it has been translocated into the membrane of the ER (eukaryotes) or plasma membrane (prokaryotes) by signal peptidase. The signal sequence of type II membrane proteins and some polytopic membrane proteins are not cleaved off and therefore are referred to as signal anchor sequences. Within the ER, the protein is first covered by a chaperone protein to protect it from the high concentration of other proteins in the ER, giving it time to fold correctly. Once folded, the protein is modified as needed (for example, by glycosylation), then transported to the Golgi for further processing and goes to its target organelles or is retained in the ER by various ER retention mechanisms. The amino acid chain of transmembrane proteins, which often are transmembrane receptors, passes through a membrane one or several times. These proteins are inserted into the membrane by translocation, until the process is interrupted by a stop-transfer sequence, also called a membrane anchor or signal-anchor sequence. These complex membrane proteins are currently characterized using the same model of targeting that has been developed for secretory proteins. However, many complex multi-transmembrane proteins contain structural aspects that do not fit this model. Seven transmembrane G-protein coupled receptors (which represent about 5% of the genes in humans) mostly do not have an amino-terminal signal sequence. In contrast to secretory proteins, the first transmembrane domain acts as the first signal sequence, which targets them to the ER membrane. This also results in the translocation of the amino terminus of the protein into the ER membrane lumen. This translocation, which has been demonstrated with opsin with in vitro experiments, breaks the usual pattern of "co-translational" translocation which has always held for mammalian proteins targeted to the ER. A great deal of the mechanics of transmembrane topology and folding remains to be elucidated. Post-translational translocation Even though most secretory proteins are co-translationally translocated, some are translated in the cytosol and later transported to the ER/plasma membrane by a post-translational system. In prokaryotes this process requires certain cofactors such as SecA and SecB and is facilitated by Sec62 and Sec63, two membrane-bound proteins. The Sec63 complex, which is embedded in the ER membrane, causes hydrolysis of ATP, allowing chaperone proteins to bind to an exposed peptide chain and slide the polypeptide into the ER lumen. Once in the lumen the polypeptide chain can be folded properly. This process only occurs in unfolded proteins located in the cytosol. In addition, proteins targeted to other cellular destinations, such as mitochondria, chloroplasts, or peroxisomes, use specialized post-translational pathways. Proteins targeted for the nucleus are also translocated post-translationally through the addition of a nuclear localization signal (NLS) that promotes passage through the nuclear envelope via nuclear pores. Sorting of proteins Mitochondria Most mitochondrial proteins are synthesized as cytosolic precursors containing uptake peptide signals. Cytosolic chaperones deliver preproteins to channel-linked receptors in the mitochondrial membrane. The preprotein with presequence targeted for the mitochondria is bound by receptors and the general import pore (GIP), collectively known as translocase of the outer membrane (TOM), at the outer membrane. It is then translocated through TOM as hairpin loops. The preprotein is transported through the intermembrane space by small TIMs (which also acts as molecular chaperones) to the TIM23 or TIM22 (translocase of the inner membrane) at the inner membrane. Within the matrix the targeting sequence is cleaved off by mtHsp70. Three mitochondrial outer membrane receptors are known: TOM70: Binds to internal targeting peptides and acts as docking point for cytosolic chaperones. TOM20: Binds presequences. TOM22: Binds both presequences and internal targeting peptides. The TOM channel (TOM40) is a cation specific high conductance channel with a molecular weight of 410 kDa and a pore diameter of 21Å. The presequence translocase23 (TIM23) is localized to the mitochondrial	preproteins to channel-linked receptors in the mitochondrial membrane. The preprotein with presequence targeted for the mitochondria is bound by receptors and the general import pore (GIP), collectively known as translocase of the outer membrane (TOM), at the outer membrane. It is then translocated through TOM as hairpin loops. The preprotein is transported through the intermembrane space by small TIMs (which also acts as molecular chaperones) to the TIM23 or TIM22 (translocase of the inner membrane) at the inner membrane. Within the matrix the targeting sequence is cleaved off by mtHsp70. Three mitochondrial outer membrane receptors are known: TOM70: Binds to internal targeting peptides and acts as docking point for cytosolic chaperones. TOM20: Binds presequences. TOM22: Binds both presequences and internal targeting peptides. The TOM channel (TOM40) is a cation specific high conductance channel with a molecular weight of 410 kDa and a pore diameter of 21Å. The presequence translocase23 (TIM23) is localized to the mitochondrial inner membrane and acts as a pore-forming protein which binds precursor proteins with its N-terminus. TIM23 acts as a translocator for preproteins for the mitochondrial matrix, the inner mitochondrial membrane as well as for the intermembrane space. TIM50 is bound to TIM23 at the inner mitochondrial side and found to bind presequences. TIM44 is bound on the matrix side and found binding to mtHsp70. The presequence translocase22 (TIM22) binds preproteins exclusively bound for the inner mitochondrial membrane. Mitochondrial matrix targeting sequences are rich in positively charged amino acids and hydroxylated ones. Proteins are targeted to submitochondrial compartments by multiple signals and several pathways. Targeting to the outer membrane, intermembrane space, and inner membrane often requires another signal sequence in addition to the matrix targeting sequence. Chloroplasts The preprotein for chloroplasts may contain a stromal import sequence or a stromal and thylakoid targeting sequence. The majority of preproteins are translocated through the Toc and Tic complexes located within the chloroplast envelope. In the stroma the stromal import sequence is cleaved off and folded as well as intra-chloroplast sorting to thylakoids continues. Proteins targeted to the envelope of chloroplasts usually lack cleavable sorting sequence. Both chloroplasts and mitochondria Many proteins are needed in both mitochondria and chloroplasts. In general the dual-targeting peptide is of intermediate character to the two specific ones. The targeting peptides of these proteins have a high content of basic and hydrophobic amino acids, a low content of negatively charged amino acids. They have a lower content of alanine and a higher content of leucine and phenylalanine. The dual targeted proteins have a more hydrophobic targeting peptide than both mitochondrial and chloroplastic ones. However, it is tedious to predict if a peptide is dual-targeted or not based on its physico-chemical characteristics. Peroxisomes All peroxisomal proteins are encoded by nuclear genes. To date there are two types of known Peroxisome Targeting Signals (PTS): Peroxisome targeting signal 1 (PTS1): a C-terminal tripeptide with a consensus sequence (S/A/C)-(K/R/H)-(L/A). The most common PTS1 is serine-lysine-leucine (SKL). Most peroxisomal matrix proteins possess a PTS1 type signal. Peroxisome targeting signal 2 (PTS2): a nonapeptide located near the N-terminus with a consensus sequence (R/K)-(L/V/I)-XXXXX-(H/Q)-(L/A/F) (where X can be any amino acid). There are also proteins that possess neither of
and players return meld cards to their hands. Some varieties accept a "round house", kings and queens of each suit, and earn a bonus 10 points awarding a total of 250 points. Trick-taking commences and continues until all held cards have been played. One variation has no "leading" requirement for the bid winner or subsequent trick winner to lead a specific card, however the rules of "following" are still observed. When adding counters, cards from each player's discard pile are included in totals for a total of 240 counters per round, plus one counter for winning the final trick. One variation to make it more difficult for the bid-winning player, the discard pile created by drawing cards is used by the non-bidding player to score towards tricks. Three-handed In Three-handed pinochle, each player plays for him or herself. The dealer deals 15 cards to each player and three cards to the kitty—a separate pile in the middle. All players review their cards and silently determine their bids. The player to the dealer's left initiates the bidding process. If the player has a meld, he or she is required to open the bidding; otherwise, they may pass or bid. If he or she passes, the obligation to bid passes to the next player, if meld is held. Once a player passes, he or she is out of the auction. Bidding begins at 20, or as little as 19 if dealer, and increases in multiples of 1. The highest bidder wins the auction and turns up the three-card kitty for all to see. The three widow cards are placed in the bid winner's hand. The bid winner then declares trump and lays down meld. The other two players also lay meld face-up for count. After the appropriate points have been tallied the bid winner must set aside any three cards that have not been melded. This will reduce the bid winner's hand to 15 cards. For all three players, meld is now returned to each respective player's hand, and the round is played. During the round, a player must take at least one trick to "save one's meld", even if the trick contains no points; otherwise, no meld points will be counted for that player during that round. After all tricks are taken, counters are tallied for each player. The three discards by the highest bidder count toward their counter score for the hand, so there is always a total of 25 points for the trick score among the three players. If the highest bidder fails to make their contract by adding meld points and trick points from the play, then their score is negative the amount of the bid for that hand. The meld count is cancelled. After viewing the kitty, the highest bidder may concede the hand and take a negative score for the amount of their bid; however, they still must name trump and the other two players score their meld. Conceding the hand does save the trick points opponents would score playing their hands, although opponents will not have an opportunity to lose their meld by failing to take a trick. The game is won when one player reaches 100 points. It is possible for two or all three players to go over 100 on the same hand. There are three methods of resolving ties: Playing another hand The game is extended becomes a contest to 125 points. If two players exceed 125 points on the same hand, the contest lengthens to 150 points. This rule holds regardless of score fluctuations (players "going minus"—failing to reach their bid amounts—and falling below 100 points. If two players exceed 100 points on the same hand, then the high bidder for that round automatically is declared the winner. If two non-bidders exceed 100 points on the same hand, then either of the other methods apply. Renege Any time a player accidentally misplays during the play portion of the hand, it is called a renege. There are various forms of misplay: Playing out of suit Sloughing on a trick when holding trump Playing out of turn Failure to discard three cards prior to the play portion of the hand—this constitutes a renege if bidder has led to the first trick Purposely exposing any portion of your hand to another player (during the play portion of the game for all players and also during the meld portion of the hand for nonbidders with the exception of meld cards) Failure to kill (Not going over the played card when required to during the hand) Any other action that disrupts the harmony of the game After play begins, any discovered misdeal not caused by a card-fault in the deck constitutes a renege for the dealer and any player on the dealer's team. If the bidder reneges, they automatically takes a double set and the amount of the bid is subtracted from their score. The two opposing players get to count their meld points and the remainder of the hand is thrown in. If either of the two nonbidders misplay, the bidder automatically makes their bid. The bidder gets to score the amount of their bid and meld, the player that misplayed loses all meld and takes a single set, and the third player scores only their meld. If at any point during melding or play it is determined that a non-standard deck is being used, any player may declare a card-fault misdeal. This results in the nullification of the entire hand including all meld and points obtained. Cutthroat Similar to three-handed pinochle, cutthroat is a simple modification. The dealer deals the entire deck out (16 cards to each player), in packets of four. The player to the left of the dealer begins the bidding once meld has been silently determined by all players. Play continues normally in terms of scoring and trick taking. The only way to win in cutthroat pinochle, however, is to "bid and out", or to have taken the bid and surpassed the predetermined winning score. It is then possible for multiple players to go over the winning score, yet if none has taken a bid and met the resulting contract, a win has not happened and play continues. It is also possible for a person to lose with the high score if they do not take a winning bid. Four-handed Four-handed pinochle, or "partnership pinochle" is played with two teams of two players each. Partners are seated opposite from each other. Each player is dealt 12 cards. The opening bid is typically 150, but can be a higher agreed on value. All four players may bid. Both the bidder and his partner have their score count towards making the contract. High bidder names trump. There typically is no kitty. With a kitty, the four cards are distributed, one to each player, by the bid winner. Each hand must meld separately. As in the three-handed version, the first player is forced to bid when holding meld. Play is often to 1000 but can increase to 1500 during partnership. Five-handed and larger Games with five hands or more typically modify partnership pinochle in a variety of ways. They are generally played with 1 1/2 or doubled decks, with extra dix added or withheld to make an even deal. With an odd number of players, the bidder asks for a desired card in the trump suit, with the first matching player being partner for that hand. Everyone else plays against the team. In larger groups, one or more players can sit out each hand allowing the remaining players to follow the appropriate rules for the respective number of players. Check Check pinochle is a gambling variant of three-hand. It is the same as to 1000, except that players keep track of "checks". If playing for $1 stakes, each check gained means that the other two players owe a dollar. The following events cause a gain or loss of checks. Flush or run +1 check Aces +1 check Roundtable +2 checks (marriage in each suit) Note that checks for meld can be earned either by the bidder or non-bidder. Checks are kept even if the bid is not made. Looking at the "talon" and losing the hand (either by conceding or playing) −1 check Playing the hand and losing −1 additional check Not looking at the talon and conceding 300 points. – no gain or loss of checks (happens when forced to bid) Double marriage (two marriages in same suit) +1 check Double pinochle +1 check Double aces, double kings, double queens, or double jacks +2 checks Winning the game +5 or +10 checks 7 nines +5 or +10 checks (do not need to win the bid to get credit) Double-deck Today "double-deck" pinochle is a popular form of the game, exclusively played by the National Pinochle Association, the American Pinochle Association, the Cambridge Pinochle Association, and in the "World Series of Pinochle". Double-deck pinochle is played with two pinochle decks, without the nines. This makes for an 80 card deck. Play is similar to regular pinochle, except 20 cards are dealt to each person and minimum bid is increased to 500 points. In some variations, bids are made in increments of 10 or more points until 600 is reached, then by 50 points. This version often features "meld bidding", a bid made to let a partner know what is in the bidder's hand. The only communication during bidding should be a numerical number or "pass", any other way of communicating is called "talking across the table" and is forbidden. There are occasionally different meld values for a run and a pinochle; a run being 250 or 150 points, and a pinochle being 150 or 40 points. All other aspects of the game generally remain the same. Technical Misdeal If a player is dealt 13 or more non-counters and no aces, the player may declare a technical misdeal. This must declared before he or she plays the first trick. A technical misdeal nullifies all points melded for all players. The hand is then re-dealt by the original dealer of that hand. Triple-deck, six-handed This version follows the rules of double-deck pinochle. In triple-deck pinochle six play in two partnerships of three each; each player has an opponent at their right and left. Three pinochle decks with no nines are mixed together, making a pack of 120 cards. Each player is dealt 20 cards, and the rules of double deck pinochle apply, except that the minimum bid is 75, and the last trick is worth 3 points. most of the extra melds made possible by the triple pack do not count extra. i.e. if a player should hold twenty aces, five of each suit, the value would be that of double aces and triple aces combined. Internet Internet pinochle is almost always "double deck" except for a few applications for some smart phones. Today the Internet is host to many live professional cash tournaments, although many are still cautious about playing online because of potential cheating. Racehorse Note that this use of the term "racehorse" is inconsistent with the commonly understood meaning of the term when applied to Pinochle. As summarized by Dave LeVasseur: "Racehorse means that, after the winning bidder has named trump, that player's partner passes cards across the table" Played much the same as "double deck" but to six hands, the point values are inflated. Two teams are formed, 20 cards are then dealt to each player and four cards are dealt to the blind. Bidding commences with the person immediately to the left of the dealer automatically bidding 500. The winner of the bid includes the blind into their hand, calls trump and melds. Note: all runs, double, triple, and quadruple, marriages must be in trump The game continues with the standard rules of play. When the play is over each team adds up their points in the count with kings, 10s, and aces worth ten points, while queens and jacks are worth zero. If a team count plus meld does not equal their bid, they "go set". By going set the amount of the bid is subtracted from the team's score and their count is discarded. The other team retains both their meld and their count provided they took at least 10 points in the count. Eight-player double-deck Two full decks are dealt between eight players, forming four teams. Team members are spaced so that they are not able to see any other hands. The game is usually played to a score of 5,000 or higher. Other than this, the four-player rules apply, and any variations may also be used. There is an increased possibility that when one team declares trump another team may have an equal number of trump also, which may lead to an interesting game. An optional scoring rule rewards 1,000 points for a quadruple pinochle—four jacks of diamonds and four queens of spades in a meld. Alternate end games One variation on winning allows a team or individual to win instantly from any score by taking all the tricks in a hand. To win in this fashion, the winning player or team must play very skillfully to prevent opposing players from taking even one lowly (even zero-point) trick. This victory is known as "pinochling". A player or team can play for this victory even if they are not the highest bidder. "pinochling" does not require a bidder to make their bid. They also can play for this victory even if their bid cannot be made with the maximum number of trick points available plus their meld. However, the highest bidding player or team can prevent other players from attempting this if they elect to "throw in" the hand before the first card is played. When playing "bid-out" rules, a team can win without bidding if their score reaches (and remains above) the agreed-upon game-ending score while their opponents fail to make	must follow the lead suit if possible. Usually every player must play a winning card against those played so far, if it is possible to do so, even when the current player expects a later player to win the hand with a better card. The only exception is if a player played a trump card when trump was not the suit led. In that case, those following that player may play any card of the lead suit, since they must follow the lead suit but are already losing to the player who played trump. Likewise, if a player cannot follow suit, but has trump, they must play trump. Again, if a player does not have any cards of the lead suit and can play a trump card higher than any other trump played so far, the player must do so, even if the player expects that a later player will beat the card. If another trump has already been played that a player cannot beat, then they can play any trump in their hand, but they still must play a trump card if they can. Only when a player has no cards in suit, and has no trump, can the player choose to play any card in their hand. Most books of post-1945 rules say that unless trump is led, there is no requirement to try to win the trick. It is only when trump is led that "heading" the trick is mandatory. In pinochle circles and tournaments the post-1945 rules are played about half of the time according to Pagat and Hoyle. If two identical cards are played, the first one outranks the second. After the first trick, the winner of each trick leads the first card for the next trick, until all the cards are played. Scoring tricks Points are scored based on the tricks won in the hand. There are several ways to count up the points for play, but they always add up to 250 points. The last trick is always worth an additional 10 points added to any existing points in the actual trick cards. The classic counting system of pinochle is where aces are worth 11, tens are worth 10, kings are worth four, queens are worth three, jacks are worth two, and nines are worth zero. This method takes longer to count the score at the end of each hand. A simpler method is to count aces and tens for 10 points, kings and queens for five points, and jacks and nines are worth zero. An even simpler method has aces, tens, and kings worth 10 (and known as "counters"), and everything else zero ("garbage"). Since all points are multiples of ten in the third method, most players drop the redundant zero. Aces, tens, and kings won in tricks are worth one point. The meld scoring can also avoid the zero in the tenth place. Melds like 1,000 aces are thus worth 100. The terms "1,000 aces", "800 kings" and so on are often used, even though the point values are one-tenth. Game variations Two-handed Two-handed pinochle is the original pinochle game, while partnership, auction, and all other variants are derived from it. It is the game most similar to the original Bezique game, whence pinochle was derived, via the German game of Binokel. The only significant difference in its rules from Bezique is the scoring. The original version of pinochle involves a partial deal of twelve cards to both players in packets of four, leaving a stock of 24 cards. A player can score one meld after each trick won of the first 12 tricks. Melded cards can even be used to win tricks. After each trick, players draw one card from the stock into their hand starting with the trick-winning player. For the last 12 tricks, melds are taken into each player's hand and are no longer announced by the player who wins the trick. The traditional trick-taking rules apply only for these last 12 tricks. In variations of two-handed play, no cards are initially dealt, a distinction from all other variations. Instead, the entire deck is placed face-down on the playing surface between the two players to form the widow. One player begins the hand-building process by drawing the top card of the widow. The player can either keep that card for her or his hand or reject the card. If the player chooses to hold the initial card, the player then draws a second card from the widow, then places it face-down, without looking at it, creating a discard pile. If the player rejects the first card, the card becomes the first card in the discard pile. The second card drawn from the widow must be kept, regardless of whether she or he preferred the first card. Players alternate turns in this hand-building process until all cards are chosen. With bidding, the player winning the bid declares trump, then lays all meld face-up on the table. The other player shows her or his melds as well. Meld points are tallied, and players return meld cards to their hands. Some varieties accept a "round house", kings and queens of each suit, and earn a bonus 10 points awarding a total of 250 points. Trick-taking commences and continues until all held cards have been played. One variation has no "leading" requirement for the bid winner or subsequent trick winner to lead a specific card, however the rules of "following" are still observed. When adding counters, cards from each player's discard pile are included in totals for a total of 240 counters per round, plus one counter for winning the final trick. One variation to make it more difficult for the bid-winning player, the discard pile created by drawing cards is used by the non-bidding player to score towards tricks. Three-handed In Three-handed pinochle, each player plays for him or herself. The dealer deals 15 cards to each player and three cards to the kitty—a separate pile in the middle. All players review their cards and silently determine their bids. The player to the dealer's left initiates the bidding process. If the player has a meld, he or she is required to open the bidding; otherwise, they may pass or bid. If he or she passes, the obligation to bid passes to the next player, if meld is held. Once a player passes, he or she is out of the auction. Bidding begins at 20, or as little as 19 if dealer, and increases in multiples of 1. The highest bidder wins the auction and turns up the three-card kitty for all to see. The three widow cards are placed in the bid winner's hand. The bid winner then declares trump and lays down meld. The other two players also lay meld face-up for count. After the appropriate points have been tallied the bid winner must set aside any three cards that have not been melded. This will reduce the bid winner's hand to 15 cards. For all three players, meld is now returned to each respective player's hand, and the round is played. During the round, a player must take at least one trick to "save one's meld", even if the trick contains no points; otherwise, no meld points will be counted for that player during that round. After all tricks are taken, counters are tallied for each player. The three discards by the highest bidder count toward their counter score for the hand, so there is always a total of 25 points for the trick score among the three players. If the highest bidder fails to make their contract by adding meld points and trick points from the play, then their score is negative the amount of the bid for that hand. The meld count is cancelled. After viewing the kitty, the highest bidder may concede the hand and take a negative score for the amount of their bid; however, they still must name trump and the other two players score their meld. Conceding the hand does save the trick points opponents would score playing their hands, although opponents will not have an opportunity to lose their meld by failing to take a trick. The game is won when one player reaches 100 points. It is possible for two or all three players to go over 100 on the same hand. There are three methods of resolving ties: Playing another hand The game is extended becomes a contest to 125 points. If two players exceed 125 points on the same hand, the contest lengthens to 150 points. This rule holds regardless of score fluctuations (players "going minus"—failing to reach their bid amounts—and falling below 100 points. If two players exceed 100 points on the same hand, then the high bidder for that round automatically is declared the winner. If two non-bidders exceed 100 points on the same hand, then either of the other methods apply. Renege Any time a player accidentally misplays during the play portion of the hand, it is called a renege. There are various forms of misplay: Playing out of suit Sloughing on a trick when holding trump Playing out of turn Failure to discard three cards prior to the play portion of the hand—this constitutes a renege if bidder has led to the first trick Purposely exposing any portion of your hand to another player (during the play portion of the game for all players and also during the meld portion of the hand for nonbidders with the exception of meld cards) Failure to kill (Not going over the played card when required to during the hand) Any other action that disrupts the harmony of the game After play begins, any discovered misdeal not caused by a card-fault in the deck constitutes a renege for the dealer and any player on the dealer's team. If the bidder reneges, they automatically takes a double set and the amount of the bid is subtracted from their score. The two opposing players get to count their meld points and the remainder of the hand is thrown in. If either of the two nonbidders misplay, the bidder automatically makes their bid. The bidder gets to score the amount of their bid and meld, the
bacterium) or L-alanine, D-glutamine, L-lysine, and D-alanine with a 5-glycine interbridge between tetrapeptides in the case of Staphylococcus aureus (a Gram-positive bacterium). Peptidoglycan is one of the most important sources of D-amino acids in nature. Cross-linking between amino acids in different linear amino sugar chains occurs with the help of the enzyme DD-transpeptidase and results in a 3-dimensional structure that is strong and rigid. The specific amino acid sequence and molecular structure vary with the bacterial species. Biosynthesis The peptidoglycan monomers are synthesized in the cytosol and are then attached to a membrane carrier bactoprenol. Bactoprenol transports peptidoglycan monomers across the cell membrane where they are inserted into the existing peptidoglycan. In the first step of peptidoglycan synthesis, glutamine, which is an amino acid, donates an amino group to a sugar, fructose 6-phosphate. This turns fructose 6-phosphate into glucosamine-6-phosphate. In step two, an acetyl group is transferred from acetyl CoA to the amino group on the glucosamine-6-phosphate creating N-acetyl-glucosamine-6-phosphate. In step three of the synthesis process, the N-acetyl-glucosamine-6-phosphate is isomerized, which will change N-acetyl-glucosamine-6-phosphate to N-acetyl-glucosamine-1-phosphate. In step 4, the N-acetyl-glucosamine-1-phosphate, which is now a monophosphate, attacks UTP. Uridine triphosphate, which is a pyrimidine nucleotide, has the ability to act as an energy source. In this particular reaction, after the monophosphate has attacked the UTP, an inorganic pyrophosphate is given off and is replaced by the monophosphate, creating UDP-N-acetylglucosamine (2,4). (When UDP is used as an energy source, it gives off an inorganic phosphate.) This initial stage, is used to create the precursor for the NAG	glucosamine-6-phosphate. In step two, an acetyl group is transferred from acetyl CoA to the amino group on the glucosamine-6-phosphate creating N-acetyl-glucosamine-6-phosphate. In step three of the synthesis process, the N-acetyl-glucosamine-6-phosphate is isomerized, which will change N-acetyl-glucosamine-6-phosphate to N-acetyl-glucosamine-1-phosphate. In step 4, the N-acetyl-glucosamine-1-phosphate, which is now a monophosphate, attacks UTP. Uridine triphosphate, which is a pyrimidine nucleotide, has the ability to act as an energy source. In this particular reaction, after the monophosphate has attacked the UTP, an inorganic pyrophosphate is given off and is replaced by the monophosphate, creating UDP-N-acetylglucosamine (2,4). (When UDP is used as an energy source, it gives off an inorganic phosphate.) This initial stage, is used to create the precursor for the NAG in peptidoglycan. In step 5, some of the UDP-N-acetylglucosamine (UDP-GlcNAc) is converted to UDP-MurNAc (UDP-N-acetylmuramic acid) by the addition of a lactyl group to the glucosamine. Also in this reaction, the C3 hydroxyl group will remove a phosphate from the alpha carbon of phosphoenolpyruvate. This creates what is called an enol derivative that will be reduced to a “lactyl moiety” by NADPH in step six. In step 7, the UDP–MurNAc is converted to UDP-MurNAc pentapeptide by the addition of five amino acids, usually including the dipeptide D-alanyl-D-alanine. Each of these reactions requires the energy source ATP. This is all referred to as Stage one. Stage two occurs in the cytoplasmic membrane. It is in the membrane where a lipid carrier called bactoprenol carries peptidoglycan precursors through the cell membrane.
letters of words: Partial differential equation, differential equation involving partial derivatives (of a function of multiple variables) The European Democratic Party (esp.	Program development environment Pug dog encephalitis Pulse detonation engine, proposed substitute to the traditional jet engine Other modes of abbreviation: Phosphodiesterase, enzyme important in intracellular communication Polydichloric euthimal, fictional substance Pde (or Pde.), "Parade" (when serving as part of
territorial aggrandizement of the Papal States, his niece's son, Cardinal Raffaele Riario (for whom the Palazzo della Cancelleria was constructed) was suspected of colluding in the failed Pazzi conspiracy of 1478 to assassinate both Lorenzo de' Medici and his brother Giuliano and replace them in Florence with Sixtus IV's other nephew, Girolamo Riario. Francesco Salviati, Archbishop of Pisa and a main organizer of the plot, was hanged on the walls of the Florentine Palazzo della Signoria. Sixtus IV replied with an interdict and two years of war with Florence. According to the later published chronicle of the Italian historian Stefano Infessura, Diary of the City of Rome, Sixtus was a "lover of boys and sodomites", awarding benefices and bishoprics in return for sexual favours and nominating a number of young men as cardinals, some of whom were celebrated for their good looks. However, Infessura had partisan allegiances to the Colonna and so is not considered to be always reliable or impartial. The English churchman and Protestant polemicist John Bale, writing a century later, attributed to Sixtus "the authorisation to practice sodomy during periods of warm weather" to the "Cardinal of Santa Lucia". This prompted the noted historian of the Catholic Church, Ludwig von Pastor, to issue a firm rebuttal. Foreign policy Sixtus continued a dispute with King Louis XI of France, who upheld the Pragmatic Sanction of Bourges (1438), which held that papal decrees needed royal assent before they could be promulgated in France. That was a cornerstone of the privileges claimed for the Gallican Church and could never be shifted as long as Louis XI manoeuvred to replace King Ferdinand I of Naples with a French prince. Louis was thus in conflict with the papacy, and Sixtus could not permit it. On 1 November 1478, Sixtus published the papal bull Exigit Sincerae Devotionis Affectus through which the Spanish Inquisition was established in the Kingdom of Castile. Sixtus consented under political pressure from Ferdinand of Aragon, who threatened to withhold military support from his kingdom of Sicily. Nevertheless, Sixtus IV quarrelled over protocol and prerogatives of jurisdiction; he was unhappy with the excesses of the Inquisition and condemned the most flagrant abuses in 1482. As a temporal prince who constructed stout fortresses in the Papal States, he encouraged the Venetians to attack Ferrara, which he wished to obtain for another nephew. Ercole I d'Este, Duke of Ferrara, was allied with the Sforzas of Milan, the Medicis of Florence along with the King of Naples, normally a hereditary ally and champion of the papacy. The angered Italian princes allied to force Sixtus IV to make peace to his great annoyance. For refusing to desist from the very hostilities that he himself had instigated and for being a dangerous rival to Della Rovere dynastic ambitions in the Marche, Sixtus placed Venice under interdict in 1483. He also lined the coffers of the state by unscrupulously selling high offices and privileges. In ecclesiastical affairs, Sixtus promoted the dogma of the Immaculate Conception, which had been confirmed at the Council of Basle in 1439, and he designated 8 December as its feastday. In 1476, he issued the apostolic constitution Cum Praeexcelsa, establishing a Mass and Office for the feast. He formally annulled the decrees of the Council of Constance in 1478. Slavery The two papal bulls issued by Pope Nicholas V, Dum Diversas of 1452 and Romanus Pontifex of 1455, had effectively given the Portuguese the rights to acquire slaves along the African Coast by force or trade. Those concessions were confirmed by Sixtus in his own bull, Aeterni regis, of 21 June 1481. Arguably the "ideology of conquest" expounded in those texts became the means by which commerce and conversion were facilitated. In November 1476, Isabel and Fernando ordered an investigation into rights of conquest in the Canary Islands, and in the spring of 1478, they sent Juan Rejon with sixty soldiers and thirty cavalry to the Grand Canary, where the natives retreated inland. Sixtus's earlier threats to excommunicate all captains or pirates who enslaved Christians in the bull Regimini Gregis of 1476 could have been intended to emphasise the need to convert the natives of the Canary Islands and Guinea and establish a clear difference in status between those who had converted and those who resisted. The ecclesiastical penalties were directed towards those who were enslaving the recent converts. Princely patronage As a civic patron in Rome, even the anti-papal chronicler Stefano Infessura agreed that Sixtus should be admired. The dedicatory inscription in the fresco by Melozzo da Forlì in the Vatican Palace records: "You gave your city temples, streets, squares, fortifications, bridges and restored the Acqua Vergine as far as the Trevi..." In addition to restoring the aqueduct that provided Rome an alternative to the river water, which had made the city famously unhealthy, he restored or rebuilt over 30 of Rome's dilapidated churches such as San Vitale (1475) and Santa Maria del Popolo, and he added seven new ones. The Sistine Chapel was sponsored by Sixtus IV, as was the Ponte Sisto, the Sistine Bridge (the first new bridge across the Tiber since Antiquity) and the building of Via Sistina (later named Borgo Sant'Angelo), a road leading from Castel Sant'Angelo to Saint Peter.	temporal issues and dynastic considerations. Nepotism Sixtus IV sought to strengthen his position by surrounding himself with relatives and friends. In the fresco by Melozzo da Forlì, he is accompanied by his Della Rovere and Riario nephews, not all of whom were made cardinals; the protonotary apostolic Pietro Riario (on his right), the future Pope Julius II/ Giuliano Della Rovere standing before him; and Girolamo Riario and Giovanni della Rovere, behind the kneeling Platina, author of the first humanist history of the popes. His nephew, Pietro Riario, also benefited from his nepotism. Pietro became one of the richest men in Rome and was entrusted with Pope Sixtus' foreign policy. However, Pietro died prematurely in 1474, and his role passed to Giuliano Della Rovere. The secular fortunes of the Della Rovere family began when Sixtus invested his nephew Giovanni with the lordship of Senigallia and arranged his marriage to the daughter of Federico III da Montefeltro, duke of Urbino; from that union came a line of Della Rovere dukes of Urbino that lasted until the line expired, in 1631. Six of the thirty-four cardinals that he created were his nephews. In his territorial aggrandizement of the Papal States, his niece's son, Cardinal Raffaele Riario (for whom the Palazzo della Cancelleria was constructed) was suspected of colluding in the failed Pazzi conspiracy of 1478 to assassinate both Lorenzo de' Medici and his brother Giuliano and replace them in Florence with Sixtus IV's other nephew, Girolamo Riario. Francesco Salviati, Archbishop of Pisa and a main organizer of the plot, was hanged on the walls of the Florentine Palazzo della Signoria. Sixtus IV replied with an interdict and two years of war with Florence. According to the later published chronicle of the Italian historian Stefano Infessura, Diary of the City of Rome, Sixtus was a "lover of boys and sodomites", awarding benefices and bishoprics in return for sexual favours and nominating a number of young men as cardinals, some of whom were celebrated for their good looks. However, Infessura had partisan allegiances to the Colonna and so is not considered to be always reliable or impartial. The English churchman and Protestant polemicist John Bale, writing a century later, attributed to Sixtus "the authorisation to practice sodomy during periods of warm weather" to the "Cardinal of Santa Lucia". This prompted the noted historian of the Catholic Church, Ludwig von Pastor, to issue a firm rebuttal. Foreign policy Sixtus continued a dispute with King Louis XI of France, who upheld the Pragmatic Sanction of Bourges (1438), which held that papal decrees needed royal assent before they could be promulgated in France. That was a cornerstone of the privileges claimed for the Gallican Church and could never be shifted as long as Louis XI manoeuvred to replace King Ferdinand I of Naples with a French prince. Louis was thus in conflict with the papacy, and Sixtus could not permit it. On 1 November 1478, Sixtus published the papal bull Exigit Sincerae Devotionis Affectus through which the Spanish Inquisition was established in the Kingdom of Castile. Sixtus consented under political pressure from Ferdinand of Aragon, who threatened to withhold military support from his kingdom of Sicily. Nevertheless, Sixtus IV quarrelled over protocol and prerogatives of jurisdiction; he was unhappy with the excesses of the Inquisition and condemned the most flagrant abuses in 1482. As a temporal prince who constructed stout fortresses in the Papal States, he encouraged the Venetians to attack Ferrara, which he wished to obtain for another nephew. Ercole I d'Este, Duke of Ferrara, was allied with the Sforzas of Milan, the Medicis of Florence along with the King of Naples, normally a hereditary ally and champion of the papacy. The angered Italian princes allied to force Sixtus IV to make peace to his great annoyance. For refusing to desist from the very hostilities that he himself had instigated and for being a dangerous rival to Della Rovere dynastic ambitions in the Marche, Sixtus placed Venice under interdict in 1483. He also lined the coffers of the state by unscrupulously selling high offices and privileges. In ecclesiastical affairs, Sixtus promoted the dogma of the Immaculate Conception, which had been confirmed at the Council of Basle in 1439, and he designated 8 December as its feastday. In 1476, he issued the apostolic constitution Cum Praeexcelsa, establishing a Mass and Office for the feast. He formally annulled the decrees of the Council of Constance in 1478. Slavery The two papal bulls issued by Pope Nicholas V, Dum Diversas of 1452 and Romanus Pontifex of 1455, had effectively given the Portuguese the rights to acquire slaves along the African Coast by force or trade. Those concessions were confirmed by Sixtus in his own bull, Aeterni regis, of 21 June 1481. Arguably the "ideology of conquest" expounded in those texts became the means by which commerce and conversion were facilitated. In November 1476, Isabel and Fernando ordered an investigation into rights of conquest in the Canary Islands, and in the spring of 1478, they sent Juan Rejon with sixty soldiers and thirty cavalry to the Grand Canary, where the natives retreated inland. Sixtus's earlier threats to excommunicate all captains or pirates who enslaved Christians in the bull Regimini Gregis of 1476 could have been intended to emphasise the need to convert the natives of the Canary Islands and Guinea and establish a clear difference in status between those who had converted and those who resisted. The ecclesiastical penalties were directed towards those who were enslaving the recent converts. Princely patronage As a civic patron in Rome, even the anti-papal chronicler Stefano Infessura agreed that Sixtus should be admired. The dedicatory inscription in the fresco by Melozzo da Forlì in the Vatican Palace records: "You gave your city temples, streets, squares, fortifications, bridges and restored the Acqua Vergine as far as the Trevi..." In addition to restoring the aqueduct that provided Rome an alternative to the river water, which had made the city famously unhealthy, he restored or rebuilt over 30 of Rome's dilapidated churches such as San Vitale (1475) and Santa Maria del Popolo, and he added seven new ones. The Sistine Chapel was sponsored by Sixtus IV, as was the Ponte Sisto, the Sistine Bridge (the first new bridge across the Tiber since Antiquity) and the building of Via Sistina (later named Borgo Sant'Angelo), a road leading from Castel Sant'Angelo to Saint Peter. All of that was done to facilitate the integration of the Vatican Hill and Borgo with the heart of Old
November 1902 known as the "Thousand Days War." With the US being fully aware of these conditions and even incorporating them into the planning of the Panama intervention as the US acted as an arbitrator between the two sides; with the peace treaty that ended the "Thousand Days War" being signed on the USS Wisconsin on November 21, 1902. While in port the US also brought engineering teams to Panama, with the peace delegation, to begin planning for the canal's construction before the US had even gained the rights to build the canal. All these factors would result in the Colombians being unable to put down the Panamanian rebellion and expel the United States troops occupying what today is the independent nation of Panama. On November 6, 1903, Philippe Bunau-Varilla, as Panama's ambassador to the United States, signed the Hay–Bunau-Varilla Treaty, granting rights to the United States to build and indefinitely administer the Panama Canal Zone and its defenses. This is sometimes misinterpreted as the "99-year lease" because of misleading wording included in article 22 of the agreement. Almost immediately, the treaty was condemned by many Panamanians as an infringement on their country's new national sovereignty. This would later become a contentious diplomatic issue among Colombia, Panama, and the United States. President Roosevelt famously stated, "I took the Isthmus, started the canal and then left Congress not to debate the canal, but to debate me." Several parties in the United States called this an act of war on Colombia: The New York Times described the support given by the United States to Bunau-Varilla as an "act of sordid conquest." The New York Evening Post called it a "vulgar and mercenary venture." The US maneuvers are often cited as the classic example of US gunboat diplomacy in Latin America, and the best illustration of what Roosevelt meant by the old African adage, "Speak softly and carry a big stick [and] you will go far." After the revolution in 1903, the Republic of Panama became a US protectorate until 1939. In 1904, the United States purchased the French equipment and excavations, including the Panama Railroad, for US$40 million, of which $30 million related to excavations completed, primarily in the Culebra Cut, valued at about $1.00 per cubic yard. The United States also paid the new country of Panama $10 million and a $250,000 payment each following year. In 1921, Colombia and the United States entered into the Thomson–Urrutia Treaty, in which the United States agreed to pay Colombia $25 million: $5 million upon ratification, and four-$5 million annual payments, and grant Colombia special privileges in the Canal Zone. In return, Colombia recognized Panama as an independent nation. United States construction of the Panama canal, 1904–1914 The US formally took control of the canal property on May 4, 1904, inheriting from the French a depleted workforce and a vast jumble of buildings, infrastructure, and equipment, much of it in poor condition. A US government commission, the Isthmian Canal Commission (ICC), was established to oversee construction; it was given control of the Panama Canal Zone, over which the United States exercised sovereignty. The commission reported directly to Secretary of War William Howard Taft and was directed to avoid the inefficiency and corruption that had plagued the French 15 years earlier. On May 6, 1904, President Theodore Roosevelt appointed John Findley Wallace, formerly chief engineer and finally general manager of the Illinois Central Railroad, as chief engineer of the Panama Canal Project. Overwhelmed by the disease-plagued country and forced to use often dilapidated French infrastructure and equipment, as well as being frustrated by the overly bureaucratic ICC, Wallace resigned abruptly in June 1905. He was succeeded by John Frank Stevens, a self-educated engineer who had built the Great Northern Railroad. Stevens was not a member of the ICC; he increasingly viewed its bureaucracy as a serious hindrance, bypassing the commission and sending requests and demands directly to the Roosevelt administration in Washington, DC. One of Stevens' first achievements in Panama was in building and rebuilding the housing, cafeterias, hotels, water systems, repair shops, warehouses, and other infrastructure needed by the thousands of incoming workers. Stevens began the recruitment effort to entice thousands of workers from the United States and other areas to come to the Canal Zone to work. Workers from the Caribbean—called "Afro-Panamanians"—came in large numbers and many settled permanently. Stevens tried to provide accommodation in which the workers could work and live in reasonable safety and comfort. He also re-established and enlarged the railway, which was to prove crucial in transporting millions of tons of soil from the cut through the mountains to the dam across the Chagres River. Colonel William C. Gorgas had been appointed chief sanitation officer of the canal construction project in 1904. Gorgas implemented a range of measures to minimize the spread of deadly diseases, particularly yellow fever and malaria, which had recently been shown to be mosquito-borne following the work of Dr. Carlos Finlay and Dr. Walter Reed. Investment was made in extensive sanitation projects, including city water systems, fumigation of buildings, spraying of insect-breeding areas with oil and larvicide, installation of mosquito netting and window screens, and elimination of stagnant water. Despite opposition from the commission (one member said his ideas were barmy), Gorgas persisted, and when Stevens arrived, he threw his weight behind the project. After two years of extensive work, the mosquito-spread diseases were nearly eliminated. Even after all that effort, about 5,600 workers died of disease and accidents during the US construction phase of the canal. In 1905, a US engineering panel was commissioned to review the canal design, which had not been finalized. In January 1906 the panel, in a majority of eight to five, recommended to President Roosevelt a sea-level canal, as had been attempted by the French and temporarily abandoned by them in 1887 for a ten locks system designed by Philippe Bunau-Varilla, and definitively in 1898 for a lock-and-lake canal designed by the Comité Technique of the Compagnie Nouvelle de Canal de Panama as conceptualized by Adolphe Godin de Lépinay in 1879. But in 1906 Stevens, who had seen the Chagres in full flood, was summoned to Washington; he declared a sea-level approach to be "an entirely untenable proposition". He argued in favor of a canal using a lock system to raise and lower ships from a large reservoir above sea level. This would create both the largest dam (Gatun Dam) and the largest man-made lake (Gatun Lake) in the world at that time. The water to refill the locks would be taken from Gatun Lake by opening and closing enormous gates and valves and letting gravity propel the water from the lake. Gatun Lake would connect to the Pacific through the mountains at the Gaillard (Culebra) Cut. Unlike Godin de Lépinay with the Congrès International d'Etudes du Canal Interocéanique, Stevens successfully convinced Roosevelt of the necessity and feasibility of this alternative scheme. The construction of a canal with locks required the excavation of more than of material over and above the excavated by the French. As quickly as possible, the Americans replaced or upgraded the old, unusable French equipment with new construction equipment that was designed for a much larger and faster scale of work. 102 large, railroad-mounted steam shovels were purchased, 77 from Bucyrus-Erie, and 25 from the Marion Power Shovel Company. These were joined by enormous steam-powered cranes, giant hydraulic rock crushers, concrete mixers, dredges, and pneumatic power drills, nearly all of which were manufactured by new, extensive machine-building technology developed and built in the United States. The railroad also had to be comprehensively upgraded with heavy-duty, double-tracked rails over most of the line to accommodate new rolling stock. In many places, the new Gatun Lake flooded over the original rail line, and a new line had to be constructed above Gatun Lake's waterline. Goethals replaces Stevens as chief engineer In 1907, Stevens resigned as chief engineer. His replacement, appointed by President Theodore Roosevelt, was US Army Major George Washington Goethals of the US Army Corps of Engineers. Soon to be promoted to lieutenant colonel and later to general, he was a strong, West Point-trained leader and civil engineer with experience in canals (unlike Stevens). Goethals directed the work in Panama to a successful conclusion in 1914, two years ahead of the target date of June 10, 1916. Goethals divided the engineering and excavation work into three divisions: Atlantic, Central, and Pacific. The Atlantic Division, under Major William L. Sibert, was responsible for construction of the massive breakwater at the entrance to Limon Bay, the Gatun locks, and their 3½ mi (5.6 km) approach channel, and the immense Gatun Dam. The Pacific Division, under Sydney B. Williamson (the only civilian member of this high-level team), was similarly responsible for the Pacific 3 mi (4.8 km) breakwater in Panama Bay, the approach channel to the locks, and the Miraflores and Pedro Miguel locks and their associated dams and reservoirs. The Central Division, under Major David du Bose Gaillard of the United States Army Corps of Engineers, was assigned one of the most difficult parts: excavating the Culebra Cut through the continental divide to connect Gatun Lake to the Pacific Panama Canal locks. On October 10, 1913, President Woodrow Wilson sent a signal from the White House by telegraph which triggered the explosion that destroyed the Gamboa Dike. This flooded the Culebra Cut, thereby joining the Atlantic and Pacific oceans via the Panama Canal. Alexandre La Valley (a floating crane built by Lobnitz & Company and launched in 1887) was the first self-propelled vessel to transit the canal from ocean to ocean. This vessel crossed the canal from the Atlantic in stages during construction, finally reaching the Pacific on January 7, 1914. SS Cristobal (a cargo and passenger ship built by Maryland Steel, and launched in 1902 as SS Tremont) on August 3, 1914, was the first ship to transit the canal from ocean to ocean. The construction of the canal was completed in 1914, 401 years after Panama was first crossed overland by Europeans by Vasco Núñez de Balboa's party of conquistadores. The United States spent almost $500 million (roughly equivalent to $ billion in ) to finish the project. This was by far the largest American engineering project to date. The canal was formally opened on August 15, 1914, with the passage of the cargo ship . The opening of the Panama Canal in 1914 caused a severe drop in traffic along Chilean ports due to shifts in maritime trade routes. The burgeoning sheep farming business in southern Patagonia suffered a significant setback by the change in trade routes, as did the economy of the Falkland Islands. Throughout this time, Ernest "Red" Hallen was hired by the Isthmian Canal Commission to document the progress of the work. Later developments By the 1930s, water supply became an issue for the canal, prompting construction of the Madden Dam across the Chagres River above Gatun Lake. Completed in 1935, the dam created Madden Lake (later Alajeula Lake), which provides additional water storage for the canal. In 1939, construction began on a further major improvement: a new set of locks large enough to carry the larger warships that the United States was building at the time and planned to continue building. The work proceeded for several years, and significant excavation was carried out on the new approach channels, but the project was canceled after World War II. After World War II, US control of the canal and the Canal Zone surrounding it became contentious; relations between Panama and the United States became increasingly tense. Many Panamanians felt that the Zone rightfully belonged to Panama; student protests were met by the fencing-in of the zone and an increased military presence there. Demands for the United States to hand over the canal to Panama increased after the Suez Crisis in 1956, when the United States used financial and diplomatic pressure to force France and the UK to abandon their attempt to retake control of the Suez Canal, previously nationalized by the Nasser regime in Egypt. Panamanian unrest culminated in riots on Martyr's Day, January 9, 1964, when about 20 Panamanians and 3–5 US soldiers were killed. A decade later, in 1974, negotiations toward a settlement began and resulted in the Torrijos–Carter Treaties. On September 7, 1977, the treaty was signed by President of the United States Jimmy Carter and Omar Torrijos, de facto leader of Panama. This mobilized the process of granting the Panamanians free control of the canal so long as Panama signed a treaty guaranteeing the permanent neutrality of the canal. The treaty led to full Panamanian control effective at noon on December 31, 1999, and the Panama Canal Authority (ACP) assumed command of the waterway. The Panama Canal remains one of the chief revenue sources for Panama. Before this handover, the government of Panama held an international bid to negotiate a 25-year contract for operation of the container shipping ports located at the canal's Atlantic and Pacific outlets. The contract was not affiliated with the ACP or Panama Canal operations and was won by the firm Hutchison Whampoa, a Hong Kong–based shipping interest owned by Li Ka-shing. Canal Layout While globally the Atlantic Ocean is east of the isthmus and the Pacific is west, the general direction of the canal passage from the Atlantic to the Pacific is from northwest to southeast, because of the shape of the isthmus at the point the canal occupies. The Bridge of the Americas () at the Pacific side is about a third of a degree east of the Colón end on the Atlantic side. Still, in formal nautical communications, the simplified directions "southbound" and "northbound" are used. The canal consists of artificial lakes, several improved and artificial channels, and three sets of locks. An additional artificial lake, Alajuela Lake (known during the American era as Madden Lake), acts as a reservoir for the canal. The layout of the canal as seen by a ship passing from the Atlantic to the Pacific is: From the formal marking line of the Atlantic Entrance, one enters Limón Bay (Bahía Limón), a large natural harbor. The entrance runs . It provides a deepwater port (Cristóbal), with facilities like multimodal cargo exchange (to and from train) and the Colón Free Trade Zone (a free port). A channel forms the approach to the locks from the Atlantic side. The Gatun Locks, a three-stage flight of locks long, lifts ships to the Gatun Lake level, some above sea level. Gatun Lake, an artificial lake formed by the building of the Gatun Dam, carries vessels across the isthmus. It is the summit canal stretch, fed by the Gatun River and emptied by basic lock operations. From the lake, the Chagres River, a natural waterway enhanced by the damming of Gatun Lake, runs about . Here the upper Chagres River feeds the high-level-canal stretch. The Culebra Cut slices through the mountain ridge, crosses the continental divide and passes under the Centennial Bridge. The single-stage Pedro Miguel Lock, which is long, is the first part of the descent with a lift of . The artificial Miraflores Lake long, and above sea level. The two-stage Miraflores Locks is long, with a total descent of at mid-tide. From the Miraflores Locks one reaches Balboa harbor, again with multimodal exchange provision (here the railway meets the shipping route again). Nearby is Panama City. From this harbor an entrance/exit channel leads to the Pacific Ocean (Gulf of Panama), from the Miraflores Locks, passing under the Bridge of the Americas. Thus, the total length of the canal is . Navigation Gatun Lake Created in 1913 by damming the Chagres River, the Gatun Lake is a key part of the Panama Canal, providing the millions of liters of water necessary to operate its locks each time a ship passes through. At time of formation, Gatun Lake was the largest man-made lake in the world. The impassable rainforest around the lake has been the best defense of the Panama Canal. Today these areas remain practically unscathed by human interference and are one of the few accessible areas where various native Central American animal and plant species can be observed undisturbed in their natural habitat. The largest island on Gatun Lake is Barro Colorado Island. It was established for scientific study when the lake was formed, and is operated by the Smithsonian Institution. Many important scientific and biological discoveries of the tropical animal and plant kingdom originated here. Gatun Lake covers about , a vast tropical ecological zone and part of the Atlantic Forest Corridor. Ecotourism on the lake has become an industry for Panamanians. Gatun Lake also provides drinking water for Panama City and Colón. Fishing is one of the primary recreational pursuits on Gatun Lake. Non-native peacock bass were introduced by accident to Gatun Lake around 1967 by a local businessman, and have since flourished to become the dominant angling game fish in Gatun Lake. Locally called Sargento and believed to be the species Cichla pleiozona, these peacock bass originate from the Amazon, Rio Negro, and Orinoco river basins, where they are considered a premier game fish. Lock size The size of the locks determines the maximum size ship that can pass through. Because of the importance of the canal to international trade, many ships are built to the maximum size allowed. These are known as Panamax vessels. A Panamax cargo ship typically has a deadweight tonnage (DWT) of 65,000–80,000 tons, but its actual cargo is restricted to about 52,500 tons because of the draft restrictions within the canal. The longest ship ever to transit the canal was the San Juan Prospector (now Marcona Prospector), an ore-bulk-oil carrier that is long with a beam of . Initially the locks at Gatun were designed to be wide. In 1908, the United States Navy requested that an increased width of at least to allow the passage of US naval ships. Eventually a compromise was made and the locks were built wide. Each lock is long, with the walls ranging in thickness from at the base to at the top. The central wall between the parallel locks at Gatun is thick and over high. The steel lock gates measure an average of thick, wide, and high. Panama Canal pilots were initially unprepared to handle the significant flight deck overhang of aircraft carriers. knocked over all the adjacent concrete lamp posts while passing through the Gatun Locks for the first time in 1928. It is the size of the locks, specifically the Pedro Miguel Locks, along with the height of the Bridge of the Americas at Balboa, that determine the Panamax metric and limit the size of ships that may use the canal. The 2006 third set of locks project has created larger locks, allowing bigger ships to transit through deeper and wider channels. The allowed dimensions of ships using these locks increased by 25 percent in length, 51 percent in beam, and 26 percent in draft, as defined by New Panamax metrics. Tolls As with a toll road, vessels transiting the canal must pay tolls. Tolls for the canal are set by the Panama Canal Authority and are based on vessel type, size, and the type of cargo. For container ships, the toll is assessed on the ship's capacity expressed in twenty-foot equivalent units (TEUs), one TEU being the size of a standard intermodal shipping container. Effective April 1, 2016, this toll went from US$74 per loaded container to $60 per TEU capacity plus $30 per loaded container for a potential $90 per TEU when the ship is full. A Panamax container ship may carry up to . The toll is calculated differently for passenger ships and for container ships carrying no cargo ("in ballast"). , the ballast rate is US$60, down from US$65.60 per TEU. Passenger vessels in excess of 30,000 tons (PC/UMS) pay a rate based on the number of berths, that is, the number of passengers that can be accommodated in permanent beds. The per-berth charge since April 1, 2016 is $111 for unoccupied berths and $138 for occupied berths in the Panamax locks. Started in 2007, this fee has greatly increased the tolls for such ships. Passenger vessels of less than 30,000 tons or less than 33 tons per passenger are charged according to the same per-ton schedule as are freighters. Almost all major cruise ships have more than 33 tons per passenger; the rule of thumb for cruise line comfort is generally given as a minimum of 40 tons per passenger. Most other types of vessel pay a toll per PC/UMS net ton, in which one "ton" is actually a volume of . (The calculation of tonnage for commercial vessels is quite complex.) , this toll is US$5.25 per ton for the first 10,000 tons, US$5.14 per ton for the next 10,000 tons, and US$5.06 per ton thereafter. As with container ships, reduced tolls are charged for freight ships "in ballast", $4.19, $4.12, $4.05 respectively. On 1 April 2016, a more complicated toll system was introduced, having the neopanamax locks at a higher rate in some cases, natural gas transport as a new separate category and other changes. As of October 1, 2017, there are modified tolls and categories of tolls in effect. Small (less than 125 ft) vessels up to 583 PC/UMS net tons when carrying passengers or cargo, or up to 735 PC/UMS net tons when in ballast, or up to 1,048 fully loaded displacement tons, are assessed minimum tolls based upon their length overall, according to the following table (as of 29 April 2015): Morgan Adams of Los Angeles, California, holds the distinction of paying the first toll received by the United States Government for the use of the Panama Canal by a pleasure boat. His boat Lasata passed through the Zone on August 14, 1914. The crossing occurred during a sea voyage from Jacksonville, Florida, to Los Angeles in 1914. The most expensive regular toll for canal passage to date was charged on April 14, 2010, to the cruise ship Norwegian Pearl, which paid US$375,600. The average toll is around US$54,000. The highest fee for priority passage charged through the Transit Slot Auction System was US$220,300, paid on August 24, 2006, by the Panamax tanker Erikoussa, bypassing a 90-ship queue waiting for the end of maintenance work on the Gatun Locks, and thus avoiding a seven-day delay. The normal fee would have been just US$13,430. The lowest toll ever paid was 36 cents	French effort went bankrupt in 1889 after reportedly spending US$287,000,000; an estimated 22,000 men died from disease and accidents, and the savings of 800,000 investors were lost. Work was suspended on May 15, and in the ensuing scandal, known as the Panama affair, some of those deemed responsible were prosecuted, including Gustave Eiffel. Lesseps and his son Charles were found guilty of misappropriation of funds and sentenced to five years' imprisonment. This sentence was later overturned, and the father, at age 88, was never imprisoned. In 1894, a second French company, the Compagnie Nouvelle du Canal de Panama, was created to take over the project. A minimal workforce of a few thousand people was employed primarily to comply with the terms of the Colombian Panama Canal concession, to run the Panama Railroad, and to maintain the existing excavation and equipment in salable condition. The company sought a buyer for these assets, with an asking price of US$109,000,000. In the meantime, they continued with enough activity to maintain their franchise. Phillipe Bunau-Varilla, the French manager of the New Panama Canal Company, eventually managed to persuade Lesseps that a lock-and-lake canal was more realistic than a sea-level canal.The Comité Technique, a high level technical committee, was formed by the Compagnie Nouvelle to review the studies and work—that already finished and that still ongoing—and come up with the best plan for completing the canal. The committee arrived on the Isthmus in February 1896 and went immediately, quietly and efficiently about their work of devising the best possible canal plan, which they presented on November 16, 1898. Many aspects of the plan were similar in principle to the canal that was finally built by the Americans in 1914. It was a lock canal with two high level lakes to lift ships up and over the Continental Divide. Double locks would be 738 feet long and about 30 feet deep; one chamber of each pair would be 82 feet wide, the other 59. There would be eight sets of locks, two at Bohio Soldado and two at Obispo on the Atlantic side; one at Paraiso, two at Pedro Miguel, and one at Miraflores on the Pacific. Artificial lakes would be formed by damming the Chagres River at Bohio and Alhajuela, providing both flood control and electric power. United States acquisition At this time, the President and the Senate of the United States were interested in establishing a canal across the isthmus, with some favoring a canal across Nicaragua and others advocating the purchase of the French interests in Panama. Bunau-Varilla, who was seeking American involvement, asked for $100 million, but accepted $40 million in the face of the Nicaraguan option. In June 1902, the US Senate voted in favor of the Spooner Act, to pursue the Panamanian option, provided the necessary rights could be obtained. On January 22, 1903, the Hay–Herrán Treaty was signed by United States Secretary of State John M. Hay and Colombian Chargé Dr. Tomás Herrán. For $10 million and an annual payment, it would have granted the United States a renewable lease in perpetuity from Colombia on the land proposed for the canal. The treaty was ratified by the US Senate on March 14, 1903, but the Senate of Colombia did not ratify it. Bunau-Varilla told President Theodore Roosevelt and Hay of a possible revolt by Panamanian rebels who aimed to separate from Colombia, and hoped that the United States would support the rebels with US troops and money. Roosevelt changed tactics, based in part on the Mallarino–Bidlack Treaty of 1846, and actively supported the separation of Panama from Colombia. Shortly after recognizing Panama, he signed a treaty with the new Panamanian government under terms similar to the Hay–Herrán Treaty. On November 2, 1903, US warships blocked sea lanes against possible Colombian troop movements en route to put down the Panama rebellion. Panama declared independence on November 3, 1903. The United States quickly recognized the new nation. This happened so quickly that by the time the Colombian government in Bogotá launched a response to the Panamanian uprising US troops had already entered the rebelling province. It should also be stated that the Colombian troops dispatched to Panama were hastily assembled conscripts with little training. While these Conscripts may have been able to defeat the Panamanian rebels, they would not have been able to defeat the US army troops that were supporting the Panamanian rebels. The reason why an army of conscripts was sent was because that was the best response the Colombians could gather; due to the fact that Colombia was still recovering from a civil war within Colombia that was between Liberals and Conservatives from October 1899 to November 1902 known as the "Thousand Days War." With the US being fully aware of these conditions and even incorporating them into the planning of the Panama intervention as the US acted as an arbitrator between the two sides; with the peace treaty that ended the "Thousand Days War" being signed on the USS Wisconsin on November 21, 1902. While in port the US also brought engineering teams to Panama, with the peace delegation, to begin planning for the canal's construction before the US had even gained the rights to build the canal. All these factors would result in the Colombians being unable to put down the Panamanian rebellion and expel the United States troops occupying what today is the independent nation of Panama. On November 6, 1903, Philippe Bunau-Varilla, as Panama's ambassador to the United States, signed the Hay–Bunau-Varilla Treaty, granting rights to the United States to build and indefinitely administer the Panama Canal Zone and its defenses. This is sometimes misinterpreted as the "99-year lease" because of misleading wording included in article 22 of the agreement. Almost immediately, the treaty was condemned by many Panamanians as an infringement on their country's new national sovereignty. This would later become a contentious diplomatic issue among Colombia, Panama, and the United States. President Roosevelt famously stated, "I took the Isthmus, started the canal and then left Congress not to debate the canal, but to debate me." Several parties in the United States called this an act of war on Colombia: The New York Times described the support given by the United States to Bunau-Varilla as an "act of sordid conquest." The New York Evening Post called it a "vulgar and mercenary venture." The US maneuvers are often cited as the classic example of US gunboat diplomacy in Latin America, and the best illustration of what Roosevelt meant by the old African adage, "Speak softly and carry a big stick [and] you will go far." After the revolution in 1903, the Republic of Panama became a US protectorate until 1939. In 1904, the United States purchased the French equipment and excavations, including the Panama Railroad, for US$40 million, of which $30 million related to excavations completed, primarily in the Culebra Cut, valued at about $1.00 per cubic yard. The United States also paid the new country of Panama $10 million and a $250,000 payment each following year. In 1921, Colombia and the United States entered into the Thomson–Urrutia Treaty, in which the United States agreed to pay Colombia $25 million: $5 million upon ratification, and four-$5 million annual payments, and grant Colombia special privileges in the Canal Zone. In return, Colombia recognized Panama as an independent nation. United States construction of the Panama canal, 1904–1914 The US formally took control of the canal property on May 4, 1904, inheriting from the French a depleted workforce and a vast jumble of buildings, infrastructure, and equipment, much of it in poor condition. A US government commission, the Isthmian Canal Commission (ICC), was established to oversee construction; it was given control of the Panama Canal Zone, over which the United States exercised sovereignty. The commission reported directly to Secretary of War William Howard Taft and was directed to avoid the inefficiency and corruption that had plagued the French 15 years earlier. On May 6, 1904, President Theodore Roosevelt appointed John Findley Wallace, formerly chief engineer and finally general manager of the Illinois Central Railroad, as chief engineer of the Panama Canal Project. Overwhelmed by the disease-plagued country and forced to use often dilapidated French infrastructure and equipment, as well as being frustrated by the overly bureaucratic ICC, Wallace resigned abruptly in June 1905. He was succeeded by John Frank Stevens, a self-educated engineer who had built the Great Northern Railroad. Stevens was not a member of the ICC; he increasingly viewed its bureaucracy as a serious hindrance, bypassing the commission and sending requests and demands directly to the Roosevelt administration in Washington, DC. One of Stevens' first achievements in Panama was in building and rebuilding the housing, cafeterias, hotels, water systems, repair shops, warehouses, and other infrastructure needed by the thousands of incoming workers. Stevens began the recruitment effort to entice thousands of workers from the United States and other areas to come to the Canal Zone to work. Workers from the Caribbean—called "Afro-Panamanians"—came in large numbers and many settled permanently. Stevens tried to provide accommodation in which the workers could work and live in reasonable safety and comfort. He also re-established and enlarged the railway, which was to prove crucial in transporting millions of tons of soil from the cut through the mountains to the dam across the Chagres River. Colonel William C. Gorgas had been appointed chief sanitation officer of the canal construction project in 1904. Gorgas implemented a range of measures to minimize the spread of deadly diseases, particularly yellow fever and malaria, which had recently been shown to be mosquito-borne following the work of Dr. Carlos Finlay and Dr. Walter Reed. Investment was made in extensive sanitation projects, including city water systems, fumigation of buildings, spraying of insect-breeding areas with oil and larvicide, installation of mosquito netting and window screens, and elimination of stagnant water. Despite opposition from the commission (one member said his ideas were barmy), Gorgas persisted, and when Stevens arrived, he threw his weight behind the project. After two years of extensive work, the mosquito-spread diseases were nearly eliminated. Even after all that effort, about 5,600 workers died of disease and accidents during the US construction phase of the canal. In 1905, a US engineering panel was commissioned to review the canal design, which had not been finalized. In January 1906 the panel, in a majority of eight to five, recommended to President Roosevelt a sea-level canal, as had been attempted by the French and temporarily abandoned by them in 1887 for a ten locks system designed by Philippe Bunau-Varilla, and definitively in 1898 for a lock-and-lake canal designed by the Comité Technique of the Compagnie Nouvelle de Canal de Panama as conceptualized by Adolphe Godin de Lépinay in 1879. But in 1906 Stevens, who had seen the Chagres in full flood, was summoned to Washington; he declared a sea-level approach to be "an entirely untenable proposition". He argued in favor of a canal using a lock system to raise and lower ships from a large reservoir above sea level. This would create both the largest dam (Gatun Dam) and the largest man-made lake (Gatun Lake) in the world at that time. The water to refill the locks would be taken from Gatun Lake by opening and closing enormous gates and valves and letting gravity propel the water from the lake. Gatun Lake would connect to the Pacific through the mountains at the Gaillard (Culebra) Cut. Unlike Godin de Lépinay with the Congrès International d'Etudes du Canal Interocéanique, Stevens successfully convinced Roosevelt of the necessity and feasibility of this alternative scheme. The construction of a canal with locks required the excavation of more than of material over and above the excavated by the French. As quickly as possible, the Americans replaced or upgraded the old, unusable French equipment with new construction equipment that was designed for a much larger and faster scale of work. 102 large, railroad-mounted steam shovels were purchased, 77 from Bucyrus-Erie, and 25 from the Marion Power Shovel Company. These were joined by enormous steam-powered cranes, giant hydraulic rock crushers, concrete mixers, dredges, and pneumatic power drills, nearly all of which were manufactured by new, extensive machine-building technology developed and built in the United States. The railroad also had to be comprehensively upgraded with heavy-duty, double-tracked rails over most of the line to accommodate new rolling stock. In many places, the new Gatun Lake flooded over the original rail line, and a new line had to be constructed above Gatun Lake's waterline. Goethals replaces Stevens as chief engineer In 1907, Stevens resigned as chief engineer. His replacement, appointed by President Theodore Roosevelt, was US Army Major George Washington Goethals of the US Army Corps of Engineers. Soon to be promoted to lieutenant colonel and later to general, he was a strong, West Point-trained leader and civil engineer with experience in canals (unlike Stevens). Goethals directed the work in Panama to a successful conclusion in 1914, two years ahead of the target date of June 10, 1916. Goethals divided the engineering and excavation work into three divisions: Atlantic, Central, and Pacific. The Atlantic Division, under Major William L. Sibert, was responsible for construction of the massive breakwater at the entrance to Limon Bay, the Gatun locks, and their 3½ mi (5.6 km) approach channel, and the immense Gatun Dam. The Pacific Division, under Sydney B. Williamson (the only civilian member of this high-level team), was similarly responsible for the Pacific 3 mi (4.8 km) breakwater in Panama Bay, the approach channel to the locks, and the Miraflores and Pedro Miguel locks and their associated dams and reservoirs. The Central Division, under Major David du Bose Gaillard of the United States Army Corps of Engineers, was assigned one of the most difficult parts: excavating the Culebra Cut through the continental divide to connect Gatun Lake to the Pacific Panama Canal locks. On October 10, 1913, President Woodrow Wilson sent a signal from the White House by telegraph which triggered the explosion that destroyed the Gamboa Dike. This flooded the Culebra Cut, thereby joining the Atlantic and Pacific oceans via the Panama Canal. Alexandre La Valley (a floating crane built by Lobnitz & Company and launched in 1887) was the first self-propelled vessel to transit the canal from ocean to ocean. This vessel crossed the canal from the Atlantic in stages during construction, finally reaching the Pacific on January 7, 1914. SS Cristobal (a cargo and passenger ship built by Maryland Steel, and launched in 1902 as SS Tremont) on August 3, 1914, was the first ship to transit the canal from ocean to ocean. The construction of the canal was completed in 1914, 401 years after Panama was first crossed overland by Europeans by Vasco Núñez de Balboa's party of conquistadores. The United States spent almost $500 million (roughly equivalent to $ billion in ) to finish the project. This was by far the largest American engineering project to date. The canal was formally opened on August 15, 1914, with the passage of the cargo ship . The opening of the Panama Canal in 1914 caused a severe drop in traffic along Chilean ports due to shifts in maritime trade routes. The burgeoning sheep farming business in southern Patagonia suffered a significant setback by the change in trade routes, as did the economy of the Falkland Islands. Throughout this time, Ernest "Red" Hallen was hired by the Isthmian Canal Commission to document the progress of the work. Later developments By the 1930s, water supply became an issue for the canal, prompting construction of the Madden Dam across the Chagres River above Gatun Lake. Completed in 1935, the dam created Madden Lake (later Alajeula Lake), which provides additional water storage for the canal. In 1939, construction began on a further major improvement: a new set of locks large enough to carry the larger warships that the United States was building at the time and planned to continue building. The work proceeded for several years, and significant excavation was carried out on the new approach channels, but the project was canceled after World War II. After World War II, US control of the canal and the Canal Zone surrounding it became contentious; relations between Panama and the United States became increasingly tense. Many Panamanians felt that the Zone rightfully belonged to Panama; student protests were met by the fencing-in of the zone and an increased military presence there. Demands for the United States to hand over the canal to Panama increased after the Suez Crisis in 1956, when the United States used financial and diplomatic pressure to force France and the UK to abandon their attempt to retake control of the Suez Canal, previously nationalized by the Nasser regime in Egypt. Panamanian unrest culminated in riots on Martyr's Day, January 9, 1964, when about 20 Panamanians and 3–5 US soldiers were killed. A decade later, in 1974, negotiations toward a settlement began and resulted in the Torrijos–Carter Treaties. On September 7, 1977, the treaty was signed by President of the United States Jimmy Carter and Omar Torrijos, de facto leader of Panama. This mobilized the process of granting the Panamanians free control of the canal so long as Panama signed a treaty guaranteeing the permanent neutrality of the canal. The treaty led to full Panamanian control effective at noon on December 31, 1999, and the Panama Canal Authority (ACP) assumed command of the waterway. The Panama Canal remains one of the chief revenue sources for Panama. Before this handover, the government of Panama held an international bid to negotiate a 25-year contract for operation of the container shipping ports located at the canal's Atlantic and Pacific outlets. The contract was not affiliated with the ACP or Panama Canal operations and was won by the firm Hutchison Whampoa, a Hong Kong–based shipping interest owned by Li Ka-shing. Canal Layout While globally the Atlantic Ocean is east of the isthmus and the Pacific is west, the general direction of the canal passage from the Atlantic to the Pacific is from northwest to southeast, because of the shape of the isthmus at the point the canal occupies. The Bridge of the Americas () at the Pacific side is about a third of a degree east of the Colón end on the Atlantic side. Still, in formal nautical communications, the simplified directions "southbound" and "northbound" are used. The canal consists of artificial lakes, several improved and artificial channels, and three sets of locks. An additional artificial lake, Alajuela Lake (known during the American era as Madden Lake), acts as a reservoir for the canal. The layout of the canal as seen by a ship passing from the Atlantic to the Pacific is: From the formal marking line of the Atlantic Entrance, one enters Limón Bay (Bahía Limón), a large natural harbor. The entrance runs . It provides a deepwater port (Cristóbal), with facilities like multimodal cargo exchange (to and from train) and the Colón Free Trade Zone (a free port). A channel forms the approach to the locks from the Atlantic side. The Gatun Locks, a three-stage flight of locks long, lifts ships to the Gatun Lake level, some above sea level. Gatun Lake, an artificial lake formed by the building of the Gatun Dam, carries vessels across the isthmus. It is the summit canal stretch, fed by the Gatun River and emptied by basic lock operations. From the lake, the Chagres River, a natural waterway enhanced by the damming of Gatun Lake, runs about . Here the upper Chagres River feeds the high-level-canal stretch. The Culebra Cut slices through the mountain ridge, crosses the continental divide and passes under the Centennial Bridge. The single-stage Pedro Miguel Lock, which is long, is the first part of the descent with a lift of . The artificial Miraflores Lake long, and above sea level. The two-stage Miraflores Locks is long, with a total descent of at mid-tide. From the Miraflores Locks one reaches Balboa harbor, again with multimodal exchange provision (here the railway meets the shipping route again). Nearby is Panama City. From this harbor an entrance/exit channel leads to the Pacific Ocean (Gulf of Panama), from the Miraflores Locks, passing under the Bridge of the Americas. Thus, the total length of the canal is . Navigation Gatun Lake Created in 1913 by damming the Chagres River, the Gatun Lake is a key part of the Panama Canal, providing the millions of liters of water necessary to operate its locks each time a ship passes through. At time of formation, Gatun Lake was the largest man-made lake in the world. The impassable rainforest around the lake has been the best defense of the Panama Canal. Today these areas remain practically unscathed by human interference and are one of the few accessible areas where various native Central American animal and plant species can be observed undisturbed in their natural habitat. The largest island on Gatun Lake is Barro Colorado Island. It was established for scientific study when the lake was formed, and is operated by the Smithsonian Institution. Many important scientific and biological discoveries of the tropical animal and plant kingdom originated here. Gatun Lake covers about , a vast tropical ecological zone and part of the Atlantic Forest Corridor. Ecotourism on the lake has become an industry for Panamanians. Gatun Lake also provides drinking water for Panama City and Colón. Fishing is one of the primary recreational pursuits on Gatun Lake. Non-native peacock bass were introduced by accident to Gatun Lake around 1967 by a local businessman, and have since flourished to become the dominant angling game fish in Gatun Lake. Locally called Sargento and believed to be the species Cichla pleiozona, these peacock bass originate from the Amazon, Rio Negro, and Orinoco river basins, where they are considered a premier game fish. Lock size The size of the locks determines the maximum size ship that can pass through. Because of the importance of the canal to international trade, many ships are built to the maximum size allowed. These are known as Panamax vessels. A Panamax cargo ship typically has a deadweight tonnage (DWT) of 65,000–80,000 tons, but its actual cargo is restricted to about 52,500 tons because of the draft restrictions within the canal. The longest ship ever to transit the canal was the San Juan Prospector (now Marcona Prospector), an ore-bulk-oil carrier that is long with a beam of . Initially the locks at Gatun were designed to be wide. In 1908, the United States Navy requested that an increased width of at least to allow the passage of US naval ships. Eventually a compromise was made and the locks were built wide. Each lock is long, with the walls ranging in thickness from at the base to at the top. The central wall between the parallel locks at Gatun is thick and over high. The steel lock gates measure an average of thick, wide, and high. Panama Canal pilots were initially unprepared to handle the significant flight deck overhang of aircraft carriers. knocked over all the adjacent concrete lamp posts while passing through the Gatun Locks for the first time in 1928. It is the size of the locks, specifically the Pedro Miguel Locks, along with the height of the Bridge of the Americas at Balboa, that determine the Panamax metric and limit the size of ships that may use the canal. The 2006 third set of locks project has created larger locks, allowing bigger ships to transit through deeper and wider channels. The allowed dimensions of ships using these locks increased by 25 percent in length, 51 percent in beam, and 26 percent in draft, as defined by New Panamax metrics. Tolls As with a toll road, vessels transiting the canal must pay tolls. Tolls for the canal are set by the Panama Canal Authority and are based on vessel type, size, and the type of cargo. For container ships, the toll is assessed on the ship's capacity expressed in twenty-foot equivalent units (TEUs), one TEU being the size of a standard intermodal shipping container. Effective April 1, 2016, this toll went from US$74 per loaded container to $60 per TEU capacity plus $30 per loaded container for a potential $90 per TEU when the ship is full. A Panamax container ship may carry up to . The toll is calculated differently for passenger ships and for container ships carrying no cargo ("in ballast"). , the ballast rate is US$60, down from US$65.60 per TEU. Passenger vessels in excess of 30,000 tons (PC/UMS) pay a rate based on the number of berths, that is, the number of passengers that can be accommodated in permanent beds. The per-berth charge since April 1, 2016 is $111 for unoccupied berths and
a secret government agency. Conrad's third political novel, Under Western Eyes, is connected to Russian history. Its first audience read it against the backdrop of the failed Revolution of 1905 and in the shadow of the movements and impulses that would take shape as the revolutions of 1917. Conrad's earlier novella, Heart of Darkness (1899), also had political implications, in its depiction of European colonial depredations in Africa, which Conrad witnessed during his employ in the Belgian Congo. John Steinbeck's novel The Grapes of Wrath (1939) is a depiction of the plight of the poor. However, some Steinbeck's contemporaries attacked his social and political views. Bryan Cordyack writes: "Steinbeck was attacked as a propagandist and a socialist from both the left and the right of the political spectrum. The most fervent of these attacks came from the Associated Farmers of California; they were displeased with the book's depiction of California farmers' attitudes and conduct toward the migrants. They denounced the book as a 'pack of lies' and labeled it 'communist propaganda'". Some accused Steinbeck of exaggerating camp conditions to make a political point. Steinbeck had visited the camps well before publication of the novel and argued that their inhumane nature destroyed the settlers' spirit. The Quiet American (1955) by English novelist Graham Greene questions the foundations of growing American involvement in Vietnam in the 1950s. The novel has received much attention due to its prediction of the outcome of the Vietnam War and subsequent American foreign policy since the 1950s. Graham Greene portrays a U.S. official named Pyle as so blinded by American exceptionalism that he cannot see the calamities he brings upon the Vietnamese. The book uses Greene's experiences as a war correspondent for The Times and Le Figaro in French Indochina in 1951–54. The Gay Place (1961) is a set of politically-themed novellas with interlocking plots and characters by American author Billy Lee Brammer. Set in an unnamed state identical to Texas, each novella has a different protagonist: Roy Sherwood, a member of the state legislature; Neil Christiansen, the state's junior senator; and Jay McGown, the governor's speech-writer. The governor himself, Arthur Fenstemaker, a master politician (said to have been based on Brammer's mentor Lyndon Johnson) serves as the dominant figure throughout. The book also includes characters based on Brammer, his wife Nadine, Johnson's wife Ladybird, and his brother Sam Houston Johnson. The book has been widely acclaimed one of the best American political novels ever written. 21st Century Novels Since 2000, there has been a surge of Transatlantic migrant literature in French, Spanish, and English, with new narratives about political topics relating to global debt, labor abuses, mass migration, and environmental crises in the Global South. Political fiction by contemporary novelists from the Caribbean, Sub-Saharan Africa, and Latin America directly challenges political leadership, systemic racism, and economical systems. Fatou Diome, a Senegalese immigrant living France since the 1990s, writes political fiction about her experiences on France's unwelcoming borders that are dominated by white Christian culture. The work of Guadeloupean author Maryse Condé also tackles colonialism and oppression; her best known titles are Ségou (1984) and Ségou II (1985). Set in historical Segou (now part of Mali), the novels examine the violent legacies of the slave trade, Islam, Christianity, and colonization (from 1797 to 1860). A bold critic of the presidency of Nicolas Sarkozy, French novelist Marie Ndiayes won the Prix Goncourt for "Three Strong Women"(2009) about patriarchal control. Proletarian novel The proletarian novel is written by workers, mainly for other workers. It overlaps and sometimes is synonymous with the working-class novel, socialist novel, social-problem novel (also problem novel, sociological novel, or social novel), propaganda or thesis novel, and socialist-realism novel. The intention of the writers of proletarian literature is to lift the workers from the slums by inspiring them to embrace the possibilities of social change or of a political revolution. As such, it is a form of political fiction. The proletarian novel may comment on political events, systems, and theories, and is frequently seen as an instrument to promote social reform or political revolution among the working classes. Proletarian literature is created especially by communist, socialist, and anarchist authors. It is about the lives of the poor, and the period from 1930 to 1945, in particular, produced many such novels. However, proletarian works were also produced before and after those dates. In Britain, the terms "working-class" literature, novel, etc., are more generally used. Social novel A closely related type of novel, which frequently has a political dimension, is the social novel – also known as the "social-problem" or "social-protest" novel – a "work of fiction in which a prevailing social problem, such as gender, race, or class prejudice, is dramatized through its effect on the characters of a novel". More specific examples of social problems that are addressed in such works include poverty, conditions in factories and mines, the plight of child labor, violence against women, rising criminality, and epidemics caused by overcrowding and poor sanitation in cities. Charles Dickens was a fierce critic of the poverty and social stratification of Victorian society. Karl Marx asserted that Dickens "issued to the world more political and social truths than have been uttered by all the professional politicians, publicists and moralists put together". On the other hand, George Orwell, in his essay on Dickens, wrote: "There is no clear sign that he wants the existing order to be overthrown, or that he believes it would make very much difference if it were overthrown. For in reality his target is not so much society as 'human nature'." Dickens's second novel, Oliver Twist (1839), shocked readers with its images of poverty and crime: it destroyed middle-class polemics about criminals, making any pretence to ignorance about what poverty entailed impossible. Charles Dickens's Hard Times (1854) is set in a small Midlands industrial town and particularly criticizes the effect of Utilitarianism on the lives of cities' working classes. John Ruskin declared Hard Times his favourite Dickens work due to its exploration of important social questions. Walter Allen characterised Hard Times as an unsurpassed "critique of industrial society", Notable examples This is a list of a few of the early or notable examples; others belong on the main list Panchatantra (ca. 200 BCE) by Vishnu Sarma Don Quixote (1605) by Miguel de Cervantes Simplicius Simplicissimus (1668) by Hans Jakob Christoffel von Grimmelshausen The Pilgrim's Progress (1678) by John Bunyan Persian Letters (1721) by Montesquieu The History and Adventures of an Atom (1769) by Tobias Smollett Fables and Parables (1779) by Ignacy Krasicki The Partisan Leader (1836) by Nathaniel Beverley Tucker Barnaby Rudge (1841) by Charles Dickens A Tale of Two Cities (1859) by Charles Dickens The Palliser novels (1864–1879) by Anthony Trollope War and Peace (1869) by Leo Tolstoy Demons, also known as The Possessed or The Devils (1872), by Fyodor Dostoyevsky The Gilded Age (1876) by Mark Twain and Charles Dudley Warner Democracy: An American Novel (1880) by Henry Adams The Princess Casamassima (1886) by Henry James The Bostonians (1886) by Henry James Resurrection (1899) by Leo Tolstoy NEQUA or The Problem of the Ages (1900) Jack Adams The Old New Land (1902) by Theodor Herzl Mother (1906) by Maxim Gorky The Jungle (1906) by Upton Sinclair The Ragged-Trousered Philanthropists (1914) by Robert Tressell The Trial (1925) by Franz Kafka The Castle (1926) by Franz Kafka The Career of Nicodemus Dyzma (1932) by Tadeusz Dołęga-Mostowicz Walden Two (1948) by B. F. Skinner Dark Green, Bright Red (1950) by Gore Vidal Atlas Shrugged (1957) by Ayn Rand The Manchurian Candidate (1959) by Richard Condon The Comedians (1966) by Graham Greene Cancer Ward (1967) by Aleksandr Solzhenitsyn Washington, D.C. (1967) by Gore Vidal Burr (1973) by Gore Vidal	of the world's most influential works of philosophy and political theory, both intellectually and historically. The Republic is concerned with justice (δικαιοσύνη), the order and character of the just city-state, and the just man. Other influential politically-themed works include Thomas More's Utopia (1516), Jonathan Swift's Gulliver's Travels (1726), Voltaire's Candide (1759), and Harriet Beecher Stowe's Uncle Tom's Cabin (1852). Political fiction frequently employs satire, often in the utopian and dystopian genres. This includes totalitarian dystopias of the early 20th century such as Jack London's The Iron Heel, Sinclair Lewis' It Can't Happen Here, and George Orwell's Nineteen Eighty-Four. Political satire The Greek playwright Aristophanes' plays are known for their political and social satire, particularly in his criticism of the powerful Athenian general, Cleon, in plays such as The Knights. Aristophanes is also notable for the persecution he underwent. Aristophanes' plays turned upon images of filth and disease. His bawdy style was adopted by Greek dramatist-comedian Menander, whose early play, Drunkenness, contains an attack on the politician, Callimedon. Jonathan Swift's A Modest Proposal (1729) is an 18th-century Juvenalian satirical essay in which he suggests that the impoverished Irish might ease their economic troubles by selling their children as food for rich gentlemen and ladies. The satirical hyperbole mocks heartless attitudes towards the poor, as well as British policy toward the Irish in general. George Orwell's Animal Farm (1945) is an allegorical and dystopian novella which satirises the Russian Revolution of 1917 and the Soviet Union's Stalinist era. Orwell, a democratic socialist, was a critic of Joseph Stalin and was hostile to Moscow-directed Stalinism—an attitude that had been shaped by his experiences during the Spanish Civil War. The Soviet Union, he believed, had become a brutal dictatorship, built upon a cult of personality and enforced by a reign of terror. Orwell described his Animal Farm as "a satirical tale against Stalin", and in his essay "Why I Write" (1946) he wrote that Animal Farm was the first book in which he tried, with full consciousness of what he was doing, "to fuse political purpose and artistic purpose into one whole." Orwell's most famous work, however, is Nineteen Eighty-Four (published in 1949), many of whose terms and concepts, such as Big Brother, doublethink, thoughtcrime, Newspeak, Room 101, telescreen, 2 + 2 = 5, and memory hole, have entered into common use. Nineteen Eighty-Four popularised the adjective "Orwellian", which describes official deception, secret surveillance, and manipulation of recorded history by a totalitarian or authoritarian state. 16th century The poet Jan Kochanowski's play, The Dismissal of the Greek Envoys (1578), the first tragedy written in the Polish language, recounts an incident leading up to the Trojan War. Its theme of the responsibilities of statesmanship resonates to the present day. 18th century The political comedy, The Return of the Deputy (1790), by Julian Ursyn Niemcewicz—Polish poet, playwright, statesman, and comrade-in-arms of Tadeusz Kościuszko—was written in about two weeks' time while Niemcewicz was serving as a deputy to the historic Four-Year Sejm of 1788–92. The comedy's premiere in January 1791 was an enormous success, sparking widespread debate, royal communiques, and diplomatic correspondence. As Niemcewicz had hoped, it set the stage for passage of Poland's epochal Constitution of 3 May 1791, which is regarded as Europe's first, and the world's second, modern written national constitution, after the United States Constitution implemented in 1789. The comedy pits proponents against opponents of political reforms: of abolishing the destabilizing free election of Poland's kings; of abolishing the legislatively destructive liberum veto; of granting greater rights to peasants and townspeople; of curbing the privileges of the mostly self-interested noble class; and of promoting a more active Polish role in international affairs, in the interest of stopping the depredations of Poland's neighbors, Russia, Prussia, and Austria (who will in 1795 complete the dismemberment of the Polish–Lithuanian Commonwealth). Romantic interest is provided by a rivalry between a reformer and a conservative for a young lady's hand—which is won by the proponent of reforms. 19th-century novel An early example of the political novel is The Betrothed (1827) by Alessandro Manzoni, an Italian historical novel. Set in northern Italy in 1628, during the oppressive years of direct Spanish rule, it has been seen sometimes as a veiled attack on the Austrian Empire, which controlled Italy at the time the novel was written. It has been called the most famous and widely read novel in the Italian language. In the 1840s British politician Benjamin Disraeli wrote a trilogy of novels with political themes. With Coningsby; or, The New Generation (1844), Disraeli, in historian Robert Blake's view, "infused the novel genre with political sensibility, espousing the belief that England's future as a world power depended not on the complacent old guard, but on youthful, idealistic politicians." Coningsby was followed by Sybil; or, The Two Nations (1845), another political novel, which was less idealistic and more clear-eyed than Coningsby; the "two nations" of its subtitle referred to the huge economic and social gap between the privileged few and the deprived working classes. The last of Disraeli's political-novel trilogy, Tancred; or, The New Crusade (1847), promoted the Church of England's role in reviving Britain's flagging spirituality. Ivan Turgenev wrote Fathers and Sons (1862) as a response to the growing cultural schism that he saw between Russia's liberals of the 1830s and 1840s, and the growing Russian nihilist movement among their sons. Both the nihilists and the 1830s liberals sought Western-based social
are served hot. In Australia, some parts of South Africa, New Zealand, India, and the West Indies, especially in Barbados, both forms of potato product are simply known as "chips", as are the larger "home-style" variety. In the north of New Zealand, they are sometimes affectionately known as "chippies"; however, they are marketed as "chips" throughout the country. In Australia and New Zealand, a distinction is sometimes made between "hot chips" (fried potatoes) and "chips" or "potato chips". In Bangladesh, they are generally known as "chip" or "chips", and much less frequently as "crisps" (pronounced "kirisp") and locally, alu bhaja (for their similarity to the fried potato dish, bhajji). In German-speaking countries (Austria, Germany: "Kartoffelchips", often shortened to "Chips"; Switzerland: "Pommes Chips") and in countries of the former Yugoslavia, fried thin potato slices are known as "chips" (locally pronounced very similarly to the English pronunciation), with a clear distinction from French fries. In Brazil, "home-style" potato chips are known as ("Portuguese potatoes") if their sides are relatively smooth and ("Prussian potatoes") if their sides show a wafer biscuit-like pattern, whilst American-like industrial uniform potato chips made from a fried potato purée-based dough are known as "batata chips" ("potato chips"), or just . Health concerns Most potato chips contain high levels of sodium, from salt. This has been linked to health issues such as high blood pressure. However, researchers at Queen Mary University of London in 2004 have noted that a small "bag of ready-salted crisps" contains less salt than a serving of many breakfast cereals, including "every brand of cornflakes on sale in the UK." Some potato chip companies have responded to the long-standing concerns by investing in research and development to modify existing recipes and create health-conscious products. PepsiCo research shows that about 80% of salt on chips is not sensed by the tongue before being swallowed. Frito-Lay spent $414 million in 2009 on product development, including development of salt crystals that would reduce the salt content of Lay's potato chips without adversely affecting flavor. Unsalted chips are available, e.g. the longstanding British brand Salt 'n' Shake, whose chips are not seasoned, but instead include a small salt sachet in the bag for seasoning to taste. Many other popular brands in the United States, such as Frito-Lay, also offer such a product. Another possible health concern related to potato chips is acrylamide, which is produced when potatoes are fried or baked at high temperatures. Studies show that laboratory animals exposed to high levels of acrylamide develop cancer; however, it is currently unclear whether a similar risk exists in humans. In August 2008, California Attorney General Jerry Brown announced a settlement with Frito-Lay, Kettle Foods, and Lance Inc., the makers of Cape Cod Potato Chips, for violating the state's Safe Drinking Water and Toxic Enforcement Act. The state had alleged in 2005 that potato chips from these companies failed to document that they contained high levels of acrylamide, which is listed by California since the 1990s as a carcinogen. These companies paid fines and agreed to reduce acrylamide levels to be under 275 parts per billion. Many potato chip manufacturers attempt to remove burned and thus potentially acrylamide-rich chips before the packaging process. Large scanners are used to eliminate chips worst affected by heat. Regional varieties Similar foods Another type of potato chip, notably the Pringles and Lay's Stax brands, is made by extruding or pressing a dough made from dehydrated potato flour into the desired shape before frying. This makes chips that are uniform in size and shape, which allows them to be stacked and packaged in rigid cardboard or plastic canisters. Pringles are officially branded as "potato crisps" in the US. Pringles may be termed "potato chips" in Britain, to distinguish them from traditional "crisps". Munchos, another brand that uses the term "potato crisps", has deep air pockets in its chips that give it a curved shape, though the chips themselves resemble regular bagged chips. An additional variant of potato chips exists in the form of "potato sticks", also called "shoestring potatoes". These are made as extremely thin (2 to 3 mm) versions of the popular French fry but are fried in the manner of regular salted potato chips. A hickory-smoke-flavored version is popular in Canada, going by the vending machine name "Hickory Sticks". Potato sticks are typically packaged in rigid containers, although some manufacturers use flexible pouches, similar to potato chip bags. Potato sticks were originally packed in hermetically sealed steel cans. In the 1960s, manufacturers switched to the less expensive composite canister (similar to the Pringles container). Reckitt Benckiser was a market leader in this category under the Durkee Potato Stix and French's Potato Sticks names but exited the business in 2008. In 2014, French's reentered the market. A larger variant (about 1 cm thick) made with dehydrated potatoes is marketed as Andy Capp's Pub Fries, using the theme of a long-running British comic strip, which are baked and sold in a variety of flavors. Walkers make a similar product (using the Smiths brand) called "Chipsticks" which are sold in ready-salted and salt and vinegar flavors. Some companies have also marketed baked potato chips as an alternative with lower fat content. Additionally, some varieties of fat-free chips have been made using artificial, and indigestible, fat substitutes. These became well known in the media when an ingredient	A potato chip (often just chip, or crisp in British and Irish English) is a thin slice of potato that has been either deep fried or baked until crunchy. They are commonly served as a snack, side dish, or appetizer. The basic chips are cooked and salted; additional varieties are manufactured using various flavorings and ingredients including herbs, spices, cheeses, other natural flavors, artificial flavors, and additives. Potato chips form a large part of the snack food and convenience food market in Western countries. The global potato chip market generated total revenue of US$16.49 billion in 2005. This accounted for 35.5% of the total savory snacks market in that year ($46.1 billion). History The earliest known recipe for something similar to today's potato chips is in William Kitchiner's book The Cook's Oracle published in 1817, which was a bestseller in the United Kingdom and the United States. The 1822 edition's recipe for "Potatoes fried in Slices or Shavings" reads "peel large potatoes... cut them in shavings round and round, as you would peel a lemon; dry them well in a clean cloth, and fry them in lard or dripping". An 1825 British book about French cookery calls them "Pommes de Terre frites" (second recipe) and calls for thin slices of potato fried in "clarified butter or goose dripping", drained and sprinkled with salt. Early recipes for potato chips in the US are found in Mary Randolph's Virginia House-Wife (1824) and in N.K.M. Lee's Cook's Own Book (1832), both of which explicitly cite Kitchiner. A legend associates the creation of potato chips with Saratoga Springs, New York, decades later than the first recorded recipe. By the late nineteenth century, a popular version of the story attributed the dish to George Crum, a cook at Moon's Lake House who was trying to appease an unhappy customer on August 24, 1853. The customer kept sending back his French-fried potatoes, complaining that they were too thick, too "soggy", or not salted enough. Frustrated, Crum sliced several potatoes extremely thin, fried them to a crisp, and seasoned them with extra salt. To his surprise, the customer loved them. They soon came to be called "Saratoga Chips", a name that persisted into the mid-twentieth century. A version of this story was popularized in a 1973 national advertising campaign by St. Regis Paper Company which manufactured packaging for chips, claiming that Crum's customer was Cornelius Vanderbilt. Crum was already renowned as a chef at the time, and he owned a lakeside restaurant by 1860 which he called Crum's House. The "Saratoga Chips" brand name still exists today. Production In the 20th century, potato chips spread beyond chef-cooked restaurant fare and began to be mass-produced for home consumption. The Dayton, Ohio-based Mikesell's Potato Chip Company, founded in 1910, identifies as the "oldest potato chip company in the United States". New England-based Tri-Sum Potato Chips, founded in 1908 as the Leominster Potato Chip Company, in Leominster, Massachusetts, claims to be America's first potato chip manufacturer. Flavoring In an idea originated by the Smiths Potato Crisps Company Ltd, formed in 1920, Frank Smith packaged a twist of salt with his chips in greaseproof paper bags, which were sold around London. The potato chip remained otherwise unseasoned until an important scientific development in the 1950s. After English biochemists Archer Martin and Richard Synge received a Nobel Prize for inventing partition chromatography in 1952, food scientists began to develop flavors via a gas chromatograph. After some trial and error, in 1954, Joe "Spud" Murphy, the owner of the Irish crisps company Tayto, and his employee Seamus Burke, produced the world's first seasoned chips: Cheese & Onion and Salt & Vinegar. Companies worldwide sought to buy the rights to Tayto's technique. Walkers of Leicester, England produced Cheese & Onion the same year. The first flavored chips in the United States, barbecue flavor, were being manufactured and sold by 1954. In 1958, Herr's was the
voted for a repeal of the law, prohibition was abolished in early 1932. Today, all Nordic countries except Denmark continue to have strict controls on the sale of alcohol, which is highly taxed (dutied) to the public. There are government monopolies in place for selling spirits, wine, and stronger beers in Norway (Vinmonopolet), Finland (Alko), Sweden (Systembolaget), Iceland (Vínbúðin), and the Faroe Islands (Rúsdrekkasøla Landsins). Bars and restaurants may, however, import alcoholic beverages directly or through other companies. Greenland, which is part of the Kingdom of Denmark, does not share its easier controls on the sale of alcohol. Greenland has (like Denmark) sales in food shops, but prices are typically high. Private import when travelling from Denmark is only allowed in small quantities. Russian Empire and the Soviet Union In the Russian Empire, a limited version of a Dry Law was introduced in 1914. It continued through the turmoil of the Russian Revolution of 1917 and the Russian Civil War into the period of Soviet Russia and the Soviet Union until 1925. United Kingdom Although the sale or consumption of commercial alcohol has never been prohibited by law in the United Kingdom, historically, various groups in the UK have campaigned for the prohibition of alcohol; including the Society of Friends (Quakers), The Methodist Church and other non-conformists, as well as temperance movements such as Band of Hope and temperance Chartist movements of the nineteenth century. Formed in 1853 and inspired by the Maine law in the United States, the United Kingdom Alliance aimed at promoting a similar law prohibiting the sale of alcohol in the UK. This hard-line group of prohibitionists was opposed by other temperance organisations who preferred moral persuasion to a legal ban. This division in the ranks limited the effectiveness of the temperance movement as a whole. The impotence of legislation in this field was demonstrated when the Sale of Beer Act 1854, which restricted Sunday opening hours, had to be repealed, following widespread rioting. In 1859, a prototype prohibition bill was overwhelmingly defeated in the House of Commons. On 22 March 1917, during the First World War at a crowded meeting in the Queen's Hall in London (chaired by Alfred Booth) many influential people including Agnes Weston spoke, or letters from them were read out, against alcohol consumption, calling for prohibition; General Sir Reginald Hart wrote to the meeting that "Every experienced officer knew that practically all unhappiness and crime in the Army is due to drink". At the meeting, Lord Channing said that it was a pity that the whole Cabinet did not follow the example of King George V and Lord Kitchener when in 1914 those two spoke calling for complete prohibition for the duration of the war. Edwin Scrymgeour served as Member of Parliament for Dundee between 15 November 1922 and 8 October 1931. He remains the only person to have ever been elected to the House of Commons on a prohibitionist ticket. In 1922, he defeated incumbent Liberal member Winston Churchill; winning the seat for the Scottish Prohibition Party, which he had founded in 1901, and for which he had stood for election successfully as a Dundee Burgh Councillor in 1905 and unsuccessfully as a parliamentary candidate between 1908 and 1922. North America Canada Indigenous peoples in Canada were subject to prohibitory alcohol laws under the Indian Act of 1876. Sections of the Indian Act regarding liquor were not repealed for over a hundred years, until 1985. An official, but non-binding, federal referendum on prohibition was held in 1898. Prime Minister Wilfrid Laurier's government chose not to introduce a federal bill on prohibition, mindful of the strong antipathy in Quebec. As a result, Canadian prohibition was instead enacted through laws passed by the provinces during the first twenty years of the 20th century, especially during the 1910s. Canada did, however, enact a national prohibition from 1918 to 1920 as a temporary wartime measure. Much of the rum-running during prohibition took place in Windsor, Ontario. The provinces later repealed their prohibition laws, mostly during the 1920s, although some local municipalities remain dry. Mexico Some communities in the Chiapas state of southern Mexico are under the control of the libertarian socialist Zapatista Army of National Liberation, and often ban alcohol as part of what was described as "a collective decision". This prohibition has been used by many villages as a way to decrease domestic violence and has generally been favored by women. This prohibition, however, is not recognized by federal Mexican law as the Zapatista movement is strongly opposed by the federal government. The sale and purchase of alcohol is prohibited on and the night before certain national holidays, such as Natalicio de Benito Juárez (birthdate of Benito Juárez) and Día de la Revolución, which are meant to be dry nationally. The same "dry law" applies to the days before presidential elections every six years. United States Prohibition in the United States focused on the manufacture, transportation, and sale of alcoholic beverages; exceptions were made for medicinal and religious uses. Alcohol consumption was never illegal under federal law. Nationwide Prohibition did not begin in the United States until January 1920, when the Eighteenth Amendment to the U.S. Constitution went into effect. The 18th amendment was ratified in 1919, and was repealed in December 1933 with the ratification of the Twenty-first Amendment. Concern over excessive alcohol consumption began during the American colonial era, when fines were imposed for drunken behavior and for selling liquor without a license. Protestant religious groups urged Americans to curb their drinking habits for moral and health reasons. By the 1840s the temperance movement was actively encouraging individuals to immediately stop drinking. However, the issue of slavery, and then the Civil War, overshadowed the temperance movement until the 1870s. Prohibition was a major reform movement from the 1870s until the 1920s, when nationwide prohibition went into effect. The Women's Crusade of 1873 and the Woman's Christian Temperance Union (WCTU), founded in 1874, were means through which certain women organized and demanded political action, well before they were granted the vote. The WCTU and the Prohibition Party were major players until the 20th century, when the Anti-Saloon League emerged as the movement's leader. By 1913, 9 states had statewide prohibition and 31 others had local option laws in effect. The League then turned their efforts toward attaining a constitutional amendment and grassroots support for nationwide prohibition. A new constitutional amendment submitted by Congress in December 1917 prohibited "the manufacture, sale, or transportation of intoxicating liquors within, the importation thereof into, or the exportation thereof from the United States and all territory subject to the jurisdiction thereof for beverage purposes". The amendment was ratified and became law on January 16, 1919. On October 28, 1919, Congress passed the National Prohibition Act, also known as the Volstead Act, which provided enabling legislation to implement the 18th Amendment. After a year's required delay, national prohibition began on January 16, 1920. The illicit market soon grew to about two-thirds its pre-Prohibition levels. Illegal stills flourished in remote rural areas as well as city slums, and large quantities were smuggled from Canada. Bootlegging became a major business activity for organized crime groups, under leaders such as Al Capone in Chicago and Lucky Luciano in New York City. Prohibition lost support during the Great Depression, from 1929. The repeal movement was initiated and financed by the Association Against the Prohibition Amendment, and Pauline Sabin, a wealthy Republican, founded the Women's Organization for National Prohibition Reform (WONPR). Repeal of Prohibition in the United States was accomplished with the ratification of the Twenty-first Amendment on December 5, 1933. Under its terms, states were allowed to set their own laws for the control of alcohol. Between 1832 and 1953, federal legislation prohibited the sale of alcohol to Native Americans, with very limited success. After 1953, Native American communities and reservations were permitted to pass their own local ordinances governing the sale of alcoholic beverages. In the 21st century, there are still counties and parishes within the United States known as "dry," where the sale of alcohol is prohibited or restricted. South America Venezuela In Venezuela, twenty-four hours before every election, the government prohibits the sale and distribution of alcoholic beverages throughout the national territory, including the restriction to all dealers, liquor stores, supermarkets, restaurants, wineries, pubs, bars, public entertainment, clubs and any establishment that markets alcoholic beverages. The same is done during Holy Week as a measure to reduce the alarming rate of road traffic accidents during these holidays. Oceania Australia The Australian Capital Territory (then the Federal Capital Territory) was the first jurisdiction in Australia to have prohibition laws. In 1911, King O'Malley, then Minister of Home Affairs, shepherded laws through Parliament preventing new issue or transfer of licences to sell alcohol, to address unruly behaviour among workers building the new capital city. Prohibition was partial, since possession of alcohol purchased outside of the Territory remained legal and the few pubs that had existing licences could continue to operate. The Federal Parliament repealed the laws after residents of the Federal Capital Territory voted for the end of them in a 1928 plebiscite. Since then, some state governments and local councils have enacted dry areas. This is where the purchase or consumption of alcohol is only permitted in licensed areas such as liquor	consumption, importation and brewing of, and trafficking in liquor is strictly against the law. Yemen Alcohol is banned in Yemen. Southeast Asia Brunei In Brunei, alcohol consumption and sale is banned in public. Non-Muslims are allowed to purchase a limited amount of alcohol from their point of embarcation overseas for their own private consumption, and non-Muslims who are at least the age of 18 are allowed to bring in not more than two bottles of liquor (about two litres) and twelve cans of beer per person into the country. Indonesia Alcohol sales are banned in small shops and convenience stores. Malaysia Alcohol is banned only for Muslims in Malaysia due to its Islamic faith and sharia law. Nevertheless, alcoholic products can easily be found in supermarkets, specialty shops, and convenience stores all over the country. Non-halal restaurants also typically sell alcohol. Philippines There are only restrictions during elections in the Philippines. Alcohol is prohibited from purchase two days prior to an election. The Philippine Commission on Elections may opt to extend the liquor ban. In the 2010 elections, the liquor ban was a minimum two days; in the 2013 elections, there was a proposal that it be extended to five days. This was overturned by the Supreme Court. Other than election-related prohibition, alcohol is freely sold to anyone above the legal drinking age. Thailand Alcohol sales are prohibited during elections from 18:00 the day prior to voting, until the end of the day of voting itself. Alcohol is also prohibited on major Buddhist holy days, and sometimes on royal commemoration days, such as birthdays. Thailand also enforces time-limited bans on alcohol on a daily basis. Alcohol can only be legally purchased in stores or restaurants between 11:00–14:00 and 17:00–midnight. The law is enforced by all major retailers (most notably 7-Eleven) and restaurants, but is frequently ignored by the smaller "mom and pop" stores. Hotels and resorts are exempt from the rules. The consumption of alcohol is also banned at any time within 200 meters of a filling station (where sale of alcohol is also illegal), schools, temples or hospitals as well as on board any type of road vehicle regardless of whether it is being consumed by the driver or passenger. At certain times of the year—Thai New Year (Songkran) is an example—the government may also enforce arbitrary bans on the sale and consumption of alcohol in specific public areas where large scale festivities are due to take place and large crowds are expected. Thailand strictly regulates alcohol advertising, as specified in the Alcoholic Beverage Control Act, B.E. 2551 (2008) (ABCA). Sales of alcohol via "electronic channels" (internet) are prohibited. Europe Czech Republic On 14 September 2012, the Government of the Czech Republic banned all sales of alcoholic drinks with more than 20% alcohol. From this date, it was illegal to sell such alcoholic beverages in shops, supermarkets, bars, restaurants, filling stations, e-shops etc. This measure was taken in response to the wave of methanol poisoning cases resulting in the deaths of 18 people in the Czech Republic. Since the beginning of the "methanol affair" the total number of deaths has increased to 25. The ban was to be valid until further notice, though restrictions were eased towards the end of September. The last bans on Czech alcohol with regard to the poisoning cases were lifted on 10 October 2012, when neighbouring Slovakia and Poland allowed its import once again. Nordic countries The Nordic countries, with the exception of Denmark, have had a strong temperance movement since the late-1800s, closely linked to the Christian revival movement of the late-nineteenth century, but also to several worker organisations. As an example, in 1910 the temperance organisations in Sweden had some 330,000 members, which was about 6% of a population of 5.5 million. This heavily influenced the decisions of Nordic politicians in the early 20th century. In 1907, the Faroe Islands passed a law prohibiting all sale of alcohol, which was in force until 1992. Very restricted private importation from Denmark was allowed from 1928 onwards. In 1914, Sweden put in place a rationing system, the Bratt System, in force until 1955. A referendum in 1922 rejected an attempt to enforce total prohibition. In 1915, Iceland instituted total prohibition. The ban for wine was lifted in 1922 and spirits in 1935, but beer remained prohibited until 1989 (circumvented by mixing light beer and spirits). In 1916, Norway prohibited distilled beverages, and in 1917 the prohibition was extended to also include fortified wine and beer. The wine and beer ban was lifted in 1923, and in 1927 the ban of distilled beverages was also lifted. In 1919, Finland enacted prohibition, as one of the first acts after independence from the Russian Empire. Four previous attempts to institute prohibition in the early twentieth century had failed due to opposition from the tsar. After a development similar to the one in the United States during its prohibition, with large-scale smuggling and increasing violence and crime rates, public opinion turned against the prohibition, and after a national referendum where 70% voted for a repeal of the law, prohibition was abolished in early 1932. Today, all Nordic countries except Denmark continue to have strict controls on the sale of alcohol, which is highly taxed (dutied) to the public. There are government monopolies in place for selling spirits, wine, and stronger beers in Norway (Vinmonopolet), Finland (Alko), Sweden (Systembolaget), Iceland (Vínbúðin), and the Faroe Islands (Rúsdrekkasøla Landsins). Bars and restaurants may, however, import alcoholic beverages directly or through other companies. Greenland, which is part of the Kingdom of Denmark, does not share its easier controls on the sale of alcohol. Greenland has (like Denmark) sales in food shops, but prices are typically high. Private import when travelling from Denmark is only allowed in small quantities. Russian Empire and the Soviet Union In the Russian Empire, a limited version of a Dry Law was introduced in 1914. It continued through the turmoil of the Russian Revolution of 1917 and the Russian Civil War into the period of Soviet Russia and the Soviet Union until 1925. United Kingdom Although the sale or consumption of commercial alcohol has never been prohibited by law in the United Kingdom, historically, various groups in the UK have campaigned for the prohibition of alcohol; including the Society of Friends (Quakers), The Methodist Church and other non-conformists, as well as temperance movements such as Band of Hope and temperance Chartist movements of the nineteenth century. Formed in 1853 and inspired by the Maine law in the United States, the United Kingdom Alliance aimed at promoting a similar law prohibiting the sale of alcohol in the UK. This hard-line group of prohibitionists was opposed by other temperance organisations who preferred moral persuasion to a legal ban. This division in the ranks limited the effectiveness of the temperance movement as a whole. The impotence of legislation in this field was demonstrated when the Sale of Beer Act 1854, which restricted Sunday opening hours, had to be repealed, following widespread rioting. In 1859, a prototype prohibition bill was overwhelmingly defeated in the House of Commons. On 22 March 1917, during the First World War at a crowded meeting in the Queen's Hall in London (chaired by Alfred Booth) many influential people including Agnes Weston spoke, or letters from them were read out, against alcohol consumption, calling for prohibition; General Sir Reginald Hart wrote to the meeting that "Every experienced officer knew that practically all unhappiness and crime in the Army is due to drink". At the meeting, Lord Channing said that it was a pity that the whole Cabinet did not follow the example of King George V and Lord Kitchener when in 1914 those two
drug-resistant tuberculosis (XDR-TB) drug-susceptible again and make methicillin-resistant Staphylococcus aureus (MRSA) susceptible to beta-lactam antibiotics. The major reason why thioridazine has not been utilized as an antimicrobial agent (it is a first-generation or "typical" antipsychotic medication) is due to its adverse effects on the central nervous system and cardiovascular system (particularly QT interval prolongation). The term "phenothiazines" describes the largest of the five main classes of antipsychotic drugs. These drugs have antipsychotic and, often, antiemetic properties, although they may also cause severe side effects such as extrapyramidal symptoms (including akathisia and tardive dyskinesia), hyperprolactinaemia, and the rare but potentially fatal neuroleptic malignant syndrome, as well as substantial weight gain. Use of phenothiazines has been associated with antiphospholipid syndrome, but no causal relationship has been established. Phenothiazine antipsychotics are classified into three groups that differ with respect to the substituent on nitrogen: the aliphatic compounds (bearing acyclic groups), the "piperidines" (bearing piperidine-derived groups), and the piperazine (bearing piperazine-derived substituents). Nondrug applications The synthetic dye methylene blue, containing the structure, was described in 1876. Many water-soluble phenothiazine derivatives, such as methylene blue, methylene green, thionine, and others, can be electropolymerized into conductive polymers used as electrocatalysts for NADH oxidation in enzymatic biosensors and biofuel cells. Phenothiazine is used as an anaerobic inhibitor for acrylic acid polymerization, often used as an in-process inhibitor during the purification of acrylic acid. Trade names Like many commercially significant compounds, phenothiazine has numerous trade names, including AFI-Tiazin, Agrazine, Antiverm, Biverm, Dibenzothiazine, Orimon, Lethelmin, Souframine, Nemazene, Vermitin, Padophene, Fenoverm, Fentiazine, Contaverm, Fenothiazine, Phenovarm, Ieeno, ENT 38, Helmetina, Helmetine, Penthazine, XL-50, Wurm-thional, Phenegic, Phenovis, Phenoxur, and Reconox. Former uses Phenothiazine was formerly used as an insecticide and as a drug to treat infections with parasitic worms (anthelminthic) in livestock and people, but its use for those purposes has been superseded by other chemicals. Phenothiazine was introduced by DuPont as an insecticide in 1935. About 3,500,000 pounds were sold in the US in 1944. However, because it was degraded by sunlight and air, it was difficult to determine how much to use in the field, and its use waned in the 1940s with the arrival of new pesticides like DDT that were more durable. As of July 2015 it is not registered for pesticide use in the US, Europe, or Australia. It was introduced as anthelminthic in livestock in 1940 and is considered, with thiabendazole, to be the first modern anthelminthic. The	but no causal relationship has been established. Phenothiazine antipsychotics are classified into three groups that differ with respect to the substituent on nitrogen: the aliphatic compounds (bearing acyclic groups), the "piperidines" (bearing piperidine-derived groups), and the piperazine (bearing piperazine-derived substituents). Nondrug applications The synthetic dye methylene blue, containing the structure, was described in 1876. Many water-soluble phenothiazine derivatives, such as methylene blue, methylene green, thionine, and others, can be electropolymerized into conductive polymers used as electrocatalysts for NADH oxidation in enzymatic biosensors and biofuel cells. Phenothiazine is used as an anaerobic inhibitor for acrylic acid polymerization, often used as an in-process inhibitor during the purification of acrylic acid. Trade names Like many commercially significant compounds, phenothiazine has numerous trade names, including AFI-Tiazin, Agrazine, Antiverm, Biverm, Dibenzothiazine, Orimon, Lethelmin, Souframine, Nemazene, Vermitin, Padophene, Fenoverm, Fentiazine, Contaverm, Fenothiazine, Phenovarm, Ieeno, ENT 38, Helmetina, Helmetine, Penthazine, XL-50, Wurm-thional, Phenegic, Phenovis, Phenoxur, and Reconox. Former uses Phenothiazine was formerly used as an insecticide and as a drug to treat infections with parasitic worms (anthelminthic) in livestock and people, but its use for those purposes has been superseded by other chemicals. Phenothiazine was introduced by DuPont as an insecticide in 1935. About 3,500,000 pounds were sold in the US in 1944. However, because it was degraded by sunlight and air, it was difficult to determine how much to use in the field, and its use waned in the 1940s with the arrival of new pesticides like DDT that were more durable. As of July 2015 it is not registered for pesticide use in the US, Europe, or Australia. It was introduced as anthelminthic in livestock in 1940 and is considered, with thiabendazole, to be the first modern anthelminthic. The first instances of resistance were noted in 1961. Among anthelmintics, Blizzard et al. 1990 found only paraherquamide to have similar activity to phenothiazine. It is possible that they share the same mode of action. Uses for this purpose in the US are still described but it has "virtually disappeared from the market." In the 1940s it also was introduced as antihelminthic for humans; since it was often given to children, the drug was often sold in
its artistry offers "only a kibitzer's pleasure". Macdonald called the reviews he had seen, other than McCarthy's, "cautiously unfavorable". TIME magazine's 1962 review stated that "Pale Fire does not really cohere as a satire; good as it is, the novel in the end seems to be mostly an exercise in agility – or perhaps in bewilderment", though this did not prevent TIME from including the book in its 2005 list of the 100 best English-language novels published since 1923. The first Russian translation of the novel, one created by Véra Nabokov, its dedicatee, was published in 1983 by Ardis in Ann Arbor, Michigan (Alexei Tsvetkov initially played an important role in this translation). After Nabokov's reputation was rehabilitated in the Soviet Union (his novels started being published there in 1986 and the first book composed entirely of Nabokov's works was printed in 1988), Pale Fire was published in 1991 in Sverdlovsk (in Sergei Ilyin's Russian translation). Interpretations Some readers concentrate on the apparent story, focusing on traditional aspects of fiction such as the relationship among the characters. In 1997, Brian Boyd published a much-discussed study arguing that the ghost of John Shade influenced Kinbote's contributions. He expanded this essay into a book in which he also argues that, in order to trigger Shade's poem, Hazel Shade's ghost induced Kinbote to recount his Zemblan delusions to Shade. Some readers, starting with Mary McCarthy and including Boyd, Nabokov's annotator Alfred Appel, and D. Barton Johnson, see Charles Kinbote as an alter-ego of the insane Professor V. Botkin, to whose delusions John Shade and the rest of the faculty of Wordsmith College generally condescend. Nabokov himself endorsed this reading, stating in an interview in 1962 (the novel's year of publication) that Pale Fire "is full of plums that I keep hoping somebody will find. For instance, the nasty commentator is not an ex-King of Zembla nor is he professor Kinbote. He is professor Botkin, or Botkine, a Russian and a madman." The novel's intricate structure of teasing cross-references leads readers to this "plum". The Index, supposedly created by Kinbote, features an entry for a "Botkin, V.," describing this Botkin as an "American scholar of Russian descent"—and referring to a note in the Commentary on line 894 of Shade's poem, in which no such person is directly mentioned but a character suggests that "Kinbote" is "a kind of anagram of Botkin or Botkine". In this interpretation, "Gradus" the murderer is an American named Jack Grey who wanted to kill Judge Goldsworth, whose house "Pale Fire's" commentator—whatever his "true" name is—is renting. Goldsworth had condemned Grey to an asylum from which he escaped shortly before mistakenly killing Shade, who resembled Goldsworth. Other readers see a story quite different from the apparent narrative. "Shadeans" maintain that John Shade wrote not only the poem, but the commentary as well, having invented his own death and the character of Kinbote as a literary device. According to Boyd, Andrew Field invented the Shadean theory and Julia Bader expanded it; Boyd himself espoused the theory for a time. In an alternative version of the Shadean theory, Tiffany DeRewal and Matthew Roth argued that Kinbote is not a separate person but is a dissociated, alternative personality of John Shade. (An early reviewer had mentioned that "a case might be made" for such a reading.) "Kinboteans", a decidedly smaller group, believe that Kinbote invented the existence of John Shade. Boyd credits the Kinbotean theory to Page Stegner and adds that most of its adherents are newcomers to the book. Some readers see the book as oscillating undecidably between these alternatives, like the Rubin vase (a drawing that may be two profiles or a goblet). Though a minority of commentators believe or at least accept the possibility that Zembla is as "real" as New Wye, most assume that Zembla, or at least the operetta-quaint and homosexually gratified palace life enjoyed by Charles Kinbote before he is overthrown, is imaginary in the context of the story. The name "Zembla" (taken from "Nova Zembla", a former latinization of Novaya Zemlya) may evoke popular fantasy literature about royalty such as The Prisoner of Zenda. As in other Nabokov books, however, the fiction is an exaggerated or comically distorted version of his own life as a son of privilege before the Russian Revolution and an exile afterwards, and the central murder has resemblances (emphasized by Priscilla Meyer) to Nabokov's father's murder by an assassin who was trying to kill someone else. Still other readers de-emphasize any sort of "real story" and may doubt the existence of such a thing. In the interplay of allusions and thematic links, they find a multifaceted image of English literature, criticism, or glimpses of a higher world and an afterlife. Allusions and references The first two lines of John Shade's 999-line poem, "Pale Fire", have become Nabokov's most quoted couplet: I was the shadow of the waxwing slain By the false azure in the window pane Like many of Nabokov's fictions, Pale Fire alludes to others of his. "Hurricane Lolita" is mentioned, and Pnin appears as a minor character. There are many resemblances to "Ultima Thule" and "Solus Rex", two short stories by Nabokov intended to be the first two chapters of a novel in Russian that he never continued. The placename Thule appears in Pale Fire, as does the phrase solus rex (a chess problem in which one player has no pieces but the king). The book is also full of references to culture, nature, and literature. They include: Bobolink Maud Bodkin The Brothers Karamazov Robert Browning, including "My Last Duchess" and Pippa Passes (inspired in a wood near Dulwich) Cedar, including a colloquial American meaning, juniper Ben Chapman. Some have said the newspaper headline "Red Sox Beat Yanks 5–4 On Chapman's Homer" was genuine and "[u]nearthed by Nabokov in the stacks of the Cornell Library", but others have stated no such game occurred. However, a different player, Sam Chapman of the Philadelphia Athletics, did hit a home run in the 9th inning on September 29, 1938, to defeat the Yankees, 5–4. Another player, Ray Chapman of the Cleveland Indians, was the only person killed in a Major League baseball game, dying after being struck in the head by a ball thrown by a Yankees pitcher. Charles II of England Charles VI of France, known as Charles the Well-Beloved and Charles the Mad Disa orchid and the butterflies Erebia disa and E. embla (which may lead to Disa and Embla) T. S. Eliot and Four Quartets "Der Erlkönig" Et in Arcadia ego Thomas Flatman Edsel Ford (poet) and the poem "The Image of Desire" Forever Amber Robert Frost and the poems "Stopping by Woods on a Snowy Evening" and possibly "Of a Winter's Evening" Oliver Goldsmith Gradus ad Parnassum Gutnish Thomas Hardy and the poem "Friends Beyond" (for the word "stillicide") Bret Harte and his character Colonel Starbottle Hebe and the poem "Vesennyaya Groza" ("Spring Thunderstorm") by Fyodor Tyutchev Sherlock Holmes and "The Adventure of the Empty House" A Hero of Our Time A. E. Housman, including "To an Athlete Dying Young" In Memoriam A.H.H. Strange Case of Dr Jekyll and Mr Hyde Samuel Johnson, James Boswell, Boswell's Life of Johnson and Hodge James Joyce Kalevala John Keats, including La Belle Dame sans Merci The Konungs skuggsjá or Royal Mirror Krummholz Jean de La Fontaine and "The Ant and the Grasshopper" (or cicada) Franklin Knight Lane Angus McDiarmid or MacDiarmid, author of Striking and Picturesque Delineations... The Magi, including Balthasar and Melchior Novaya Zemlya Papilio nitra (now P. zelicaon nitra) and P. indra Parthenocissus Edgar Allan Poe and the poem "To One in Paradise" (for the phrase "Dim gulf") Alexander Pope and Jonathan Swift Marcel Proust François Rabelais Red admiral butterfly, Vanessa atalanta Alberto Santos-Dumont Walter Scott, including "Glenfinlas, or Lord Ronald's Coronach", "The Lady of the Lake", and The Pirate Robert Southey, in particular, the Poet Laureate's rivalry to Lord Byron as alluded to in the latter's Don Juan dedication Speyeria diana and S. atlantis Thormodus Torfaeus Waxwing Pierinae Word golf William Wordsworth, including "The	Shade. After Shade was murdered, Kinbote acquired the manuscript, including some variants, and has taken it upon himself to oversee the poem's publication, telling readers that it lacks only line 1000. Kinbote's second story deals with King Charles II, "The Beloved", the deposed king of Zembla. King Charles escaped imprisonment by Soviet-backed revolutionaries, making use of a secret passage and brave adherents in disguise. Kinbote repeatedly claims that he inspired Shade to write the poem by recounting King Charles's escape to him and that possible allusions to the king, and to Zembla, appear in Shade's poem, especially in rejected drafts. However, no explicit reference to King Charles is to be found in the poem. Kinbote's third story is that of Gradus, an assassin dispatched by the new rulers of Zembla to kill the exiled King Charles. Gradus makes his way from Zembla through Europe and America to New Wye, suffering comic mishaps. In the last note, to the missing line 1000, Kinbote narrates how Gradus killed Shade by mistake. Towards the end of the narrative, Kinbote all but states that he is in fact the exiled King Charles, living incognito; however, enough details throughout the story, as well as direct statements of ambiguous sincerity by Kinbote towards the novel's end, suggest that King Charles and Zembla are both fictitious. In the latter interpretation, Kinbote is delusional and has built an elaborate picture of Zembla complete with samples of a constructed language as a by-product of insanity; similarly, Gradus was simply an unhinged man trying to kill Shade, and his backstory as a revolutionary assassin is also made up. In an interview, Nabokov later claimed that Kinbote killed himself after finishing the book. The critic Michael Wood has stated, "This is authorial trespassing, and we don't have to pay attention to it", but Brian Boyd has argued that internal evidence points to Kinbote's suicide. One of Kinbote's annotations to Shade's poem (corresponding to line 493) addresses the subject of suicide at some length. Explanation of the title As Nabokov pointed out himself, the title of John Shade's poem is from Shakespeare's Timon of Athens: "The moon's an arrant thief, / And her pale fire she snatches from the sun" (Act IV, scene 3), a line often taken as a metaphor about creativity and inspiration. Kinbote quotes the passage but does not recognize it, as he says he has access only to an inaccurate Zemblan translation of the play "in his Timonian cave", and in a separate note he even rails against the common practice of using quotations as titles. Some critics have noted a secondary reference in the book's title to Hamlet, where the Ghost remarks how the glow-worm "'gins to pale his uneffectual fire" (Act I, scene 5). The title is first mentioned in the foreword: "I recall seeing him from my porch, on a brilliant morning, burning a whole stack of [index cards of drafts of the poem] in the pale fire of the incinerator...". Initial reception According to Norman Page, Pale Fire excited as diverse criticism as any of Nabokov's novels. Mary McCarthy's review was extremely laudatory; the Vintage edition excerpts it on the front cover. She tried to explicate hidden references and connections. Dwight Macdonald responded by saying the book was "unreadable" and both it and McCarthy's review were as pedantic as Kinbote. Anthony Burgess, like McCarthy, extolled the book, while Alfred Chester condemned it as "a total wreck". Some other early reviews were less decided, praising the book's satire and comedy but noting its difficulty and finding its subject slight or saying that its artistry offers "only a kibitzer's pleasure". Macdonald called the reviews he had seen, other than McCarthy's, "cautiously unfavorable". TIME magazine's 1962 review stated that "Pale Fire does not really cohere as a satire; good as it is, the novel in the end seems to be mostly an exercise in agility – or perhaps in bewilderment", though this did not prevent TIME from including the book in its 2005 list of the 100 best English-language novels published since 1923. The first Russian translation of the novel, one created by Véra Nabokov, its dedicatee, was published in 1983 by Ardis in Ann Arbor, Michigan (Alexei Tsvetkov initially played an important role in this translation). After Nabokov's reputation was rehabilitated in the Soviet Union (his novels started being published there in 1986 and the first book composed entirely of Nabokov's works was printed in 1988), Pale Fire was published in 1991 in Sverdlovsk (in Sergei Ilyin's Russian translation). Interpretations Some readers concentrate on the apparent story, focusing on traditional aspects of fiction such as the relationship among the characters. In 1997, Brian Boyd published a much-discussed study arguing that the ghost of John Shade influenced Kinbote's contributions. He expanded this essay into a book in which he also argues that, in order to trigger Shade's poem, Hazel Shade's ghost induced Kinbote to recount his Zemblan delusions to Shade. Some readers, starting with Mary McCarthy and including Boyd, Nabokov's annotator Alfred Appel, and D. Barton Johnson, see Charles Kinbote as an alter-ego of the insane Professor V. Botkin, to whose delusions John Shade and the rest of the faculty of Wordsmith College generally condescend. Nabokov himself endorsed this reading, stating in an interview in 1962 (the novel's year of publication) that Pale Fire "is full of plums that I keep hoping somebody will find. For instance, the nasty commentator is not an ex-King of Zembla nor is he professor Kinbote. He is professor Botkin, or Botkine, a Russian and a madman." The novel's intricate structure of teasing cross-references leads readers to this "plum". The Index, supposedly created by Kinbote, features an entry for a "Botkin, V.," describing this Botkin as an "American scholar of Russian descent"—and referring to a note in the Commentary on line 894 of Shade's poem, in which no such person is directly mentioned but a character suggests that "Kinbote" is "a kind of anagram of Botkin or Botkine". In this interpretation, "Gradus" the murderer is an American named Jack Grey who wanted to kill Judge Goldsworth, whose house "Pale Fire's" commentator—whatever his "true" name is—is renting. Goldsworth had condemned Grey to an asylum from which he escaped shortly before mistakenly killing Shade, who resembled Goldsworth. Other readers see a story quite different from the apparent narrative. "Shadeans" maintain that John Shade wrote not only the poem, but the commentary as well, having invented his own death and the character of Kinbote as a literary device. According to Boyd, Andrew Field invented the Shadean theory and Julia Bader expanded it; Boyd himself espoused the theory for a time. In an alternative version of the Shadean theory, Tiffany DeRewal and Matthew Roth argued that Kinbote is not a separate person but is a dissociated, alternative personality of John Shade. (An early reviewer had mentioned that "a case might be made" for such a reading.) "Kinboteans", a decidedly smaller group, believe that Kinbote invented the existence of John Shade. Boyd credits the Kinbotean theory to Page Stegner and adds that most of its adherents are newcomers to the book. Some readers see the book as oscillating undecidably between these alternatives, like the Rubin vase (a drawing that may be two profiles or a goblet). Though a minority of commentators believe or at least accept the possibility that Zembla is as "real" as New Wye, most assume that Zembla, or at least the operetta-quaint and homosexually gratified palace life enjoyed by Charles Kinbote before he is overthrown, is imaginary in the context of the story. The name "Zembla" (taken from "Nova Zembla", a former latinization of Novaya Zemlya) may evoke popular fantasy literature about royalty such as The Prisoner of Zenda. As in other Nabokov books, however, the fiction is an exaggerated or comically distorted version of his own life as a son of privilege before the Russian Revolution and an exile afterwards, and the central murder has resemblances (emphasized by Priscilla Meyer) to Nabokov's father's murder by an assassin who was trying to kill someone else. Still other readers de-emphasize any sort of "real story" and may doubt the existence of such a thing. In the interplay of allusions and thematic links, they find a multifaceted image of
citrates), tartaric acid, and lecithin. Nonsynthetic compounds for food preservation Citric and ascorbic acids target enzymes that degrade fruits and vegetables, e.g., mono/polyphenol oxidase which turns surfaces of cut apples and potatoes brown. Ascorbic acid and tocopherol, which are vitamins, are common preservatives. Smoking entails exposing food to a variety of phenols, which are antioxidants. Natural preservatives include rosemary and oregano extract, hops, salt, sugar, vinegar, alcohol, diatomaceous earth and castor oil. Traditional preservatives, such as sodium benzoate have raised health concerns in the past. Benzoate was shown in a study to cause hypersensitivity in some asthma sufferers. This has caused reexamination of natural preservatives which occur in vegetables. Public awareness of food preservation Public awareness of food preservatives is uneven. Americans have a perception that food-borne illnesses happen more often in other countries. This may be true, but the occurrence of illnesses, hospitalizations, and deaths are still high. It is estimated by the Centers for Disease Control (CDC) that each year there are 76 million illnesses, 325,000 hospitalizations, and 5,000 deaths linked to food-borne illness. The increasing demand for ready-to-eat fresh food products has led to challenges for food distributors regarding the safety and quality of their foods. Artificial preservatives meet some of these challenges by preserving freshness for longer periods of time, but these preservatives can cause negative side-effects as well. Sodium nitrite is a preservative used in lunch meats, hams, sausages, hot dogs, and bacon to prevent botulism. It serves the important function of controlling the bacteria that cause botulism, but sodium nitrite can react with proteins, or during cooking at high heats, to form carcinogenic N-nitrosamines. It has also been linked to cancer in lab animals. The commonly used sodium benzoate has been found to extend the shelf life of bottled tomato paste to 40 weeks without loss of quality. However, it can form the carcinogen benzene when combined with vitamin C. Many food manufacturers have reformed their products to eliminate this combination, but a risk still exists. Consumption of sodium benzoate may also cause hyperactivity. For over 30 years, there has been a debate about whether or not preservatives and other food additives can cause hyperactivity. Studies have found that there may	that do not have strong governments to regulate food additives face either harmful levels of preservatives in foods or a complete avoidance of foods that are considered unnatural or foreign. These countries have also proven useful in case studies surrounding chemical preservatives, as they have been only recently introduced. In urban slums of highly populated countries, the knowledge about contents of food tends to be extremely low, despite consumption of these imported foods. Antimicrobial preservatives Antimicrobial preservatives prevent degradation by bacteria. This method is the most traditional and ancient type of preserving—ancient methods such as pickling and adding honey prevent microorganism growth by modifying the pH level. The most commonly used antimicrobial preservative is lactic acid. Common antimicrobial preservatives are presented in the table. Nitrates and nitrites are also antimicrobial. The detailed mechanism of these chemical compounds range from inhibiting growth of the bacteria to the inhibition of specific enzymes. Water-based home and personal care products use broad-spectrum preservatives, such as isothiazolinones and formaldehyde releasers, which may cause sensitization, leading to allergic skin. Antioxidants The oxidation process spoils most food, especially those with a high fat content. Fats quickly turn rancid when exposed to oxygen. Antioxidants prevent or inhibit the oxidation process. The most common antioxidant additives are ascorbic acid (vitamin C) and ascorbates. Thus, antioxidants are commonly added to oils, cheese, and chips. Other antioxidants include the phenol derivatives BHA, BHT, TBHQ and propyl gallate. These agents suppress the formation of hydroperoxides. Other preservatives include ethanol and methylchloroisothiazolinone. A variety of agents are added to sequester (deactivate) metal ions that otherwise catalyze the oxidation of fats. Common sequestering agents are disodium EDTA, citric acid (and citrates), tartaric acid, and lecithin. Nonsynthetic compounds for food preservation Citric and ascorbic acids target enzymes that degrade fruits and vegetables, e.g., mono/polyphenol oxidase which turns surfaces of cut apples and potatoes brown. Ascorbic acid and tocopherol, which are vitamins, are common preservatives. Smoking entails exposing food to a variety of phenols, which are antioxidants. Natural preservatives include rosemary and oregano extract, hops, salt,
defined primarily in terms of ribosomal RNA (rRNA) sequences. The "Proteobacteria" are divided into nine classes with validly published names, referred to by the Greek letters alpha through zeta, the Acidithiobacillia, Hydrogenophilalia, and Oligoflexia. These were previously regarded as subclasses of the phylum, but they are now treated as classes. These classes are monophyletic. The genus Acidithiobacillus, part of the Gammaproteobacteria until it was transferred to class Acidithiobacillia in 2013, was previously regarded as paraphyletic to the Betaproteobacteria according to multigenome alignment studies. In 2017, the Betaproteobacteria was subject to major revisions and the class Hydrogenophilalia was created to contain the order Hydrogenophilales Proteobacterial classes with validly published names include some prominent genera: e.g.: Alphaproteobacteria: Brucella, Rhizobium, Agrobacterium, Caulobacter, Rickettsia, Wolbachia, etc. Betaproteobacteria: Bordetella, Ralstonia, Neisseria, Nitrosomonas, etc. Gammaproteobacteria: Escherichia, Shigella, Salmonella, Yersinia, Buchnera, Haemophilus, Vibrio, Pseudomonas, etc. Deltaproteobacteria: Desulfovibrio, Geobacter, Bdellovibrio, etc. Epsilonproteobacteria: Helicobacter, Campylobacter, Wolinella, etc. Zetaproteobacteria: Mariprofundus, Ghiorsea Oligoflexia: Oligoflexus. Acidithiobacillia: Acidithiobacillus thiooxidans, Thermithiobacillus tepidarius Hydrogenophilalia: Hydrogenophilus thermoluteolus, Tepidiphilus margaritifer Transformation Transformation, a process in which genetic material passes from one bacterium to another, has been reported in at least 30 species of "Proteobacteria" distributed in the classes alpha, beta, gamma and epsilon. The best-studied "Proteobacteria" with respect to natural genetic transformation are the medically important human pathogens Neisseria gonorrhoeae (class beta), Haemophilus influenzae (class gamma) and Helicobacter pylori (class epsilon). Natural genetic transformation is a sexual process involving DNA transfer from one bacterial cell to another through the intervening medium and the integration of the donor sequence into the recipient genome. In pathogenic "Proteobacteria", transformation appears to serve as a DNA repair process that protects the pathogen's DNA from attack by their host's phagocytic defenses that employ oxidative free radicals. References External links Proteobacteria information from Palaeos. Proteobacteria. – J. P. Euzéby: List of Prokaryotic	of the microbiotic community in the lower reproductive tract of women. These species are associated with inflammation. Some Alphaproteobacteria can grow at very low levels of nutrients and have unusual morphology such as stalks and buds. Others include agriculturally important bacteria capable of inducing nitrogen fixation in symbiosis with plants. The type order is the Caulobacterales, comprising stalk-forming bacteria such as Caulobacter. The mitochondria of eukaryotes are thought to be descendants of an alphaproteobacterium. The Betaproteobacteria are highly metabolically diverse and contain chemolithoautotrophs, photoautotrophs, and generalist heterotrophs. The type order is the Burkholderiales, comprising an enormous range of metabolic diversity, including opportunistic pathogens. The Gammaproteobacteria are the largest class in terms of species with validly published names. The type order is the Pseudomonadales, which include the genera Pseudomonas and the nitrogen-fixing Azotobacter. The Deltaproteobacteria include bacteria that are predators on other bacteria and are important contributors to the anaerobic side of the sulfur cycle. The type order is the Myxococcales, which includes organisms with self-organising abilities such as Myxococcus spp. The Epsilonproteobacteria are often slender, Gram-negative rods that are helical or curved. The type order is the Campylobacterales, which includes important food pathogens such as Campylobacter spp. The Zetaproteobacteria are iron-oxidizing neutrophilic chemolithoautotrophs, distributed worldwide in estuaries and marine habitats. The type order is the Mariprofundales. The Hydrogenophilalia are obligate thermophiles and include heterotrophs and autotrophs. The type order is the Hydrogenophilales. The Acidithiobacillia contain only sulfur, iron, and uranium-oxidising autotrophs. The type order is the Acidithiobacillales, which includes economically important organisms used in the mining industry such as Acidithiobacillus spp. The Oligoflexia are filamentous aerobes. The type order is the Oligoflexales, which contains the genus
the most intense reaction. Heightened interest results in higher attendance, increased ticket sales, higher ratings on television broadcasts (greater ad revenue), higher pay-per-view buyrates, and sales of branded merchandise and recorded video footage. All of these contribute to the profit of the promotion company. Character/gimmick In Latin America and English-speaking countries, most wrestlers (and other on-stage performers) portray character roles, sometimes with personalities wildly different from their own. These personalities are a gimmick intended to heighten interest in a wrestler without regard to athletic ability. Some can be unrealistic and cartoon-like (such as Doink the Clown), while others carry more verisimilitude (such as Chris Jericho, The Rock, John Cena, Steve Austin, and CM Punk). In lucha libre, many characters wear masks, adopting a secret identity akin to a superhero or a supervillain, a near-sacred tradition. An individual wrestler may use his real name, or a minor variation of it, for much of his career, such as Bret Hart, John Cena and Randy Orton. Others can keep one ring name for their entire career (Shawn Michaels, CM Punk and Ricky Steamboat), or may change from time to time to better suit the demands of the audience or company. Sometimes a character is owned and trademarked by the company, forcing the wrestler to find a new one when he leaves (although a simple typeset change, such as changing Rhyno to Rhino, can get around this), and sometimes a character is owned by the wrestler. Sometimes, a wrestler may change his legal name to obtain ownership of his ring name (Andrew Martin and Warrior). Many wrestlers (such as The Rock and The Undertaker) are strongly identified with their character, even responding to the name in public or between friends. It's actually considered proper decorum for fellow wrestlers to refer to each other by their stage names/characters rather than their birth/legal names, unless otherwise introduced. A character can become so popular that it appears in other media (Hulk Hogan and El Santo) or even gives the performer enough visibility to enter politics (Antonio Inoki and Jesse Ventura). Typically, matches are staged between a protagonist (historically an audience favorite, known as a babyface, or "the good guy") and an antagonist (historically a villain with arrogance, a tendency to break rules, or other unlikable qualities, called a heel, or "the bad guy"). In recent years, however, antiheroes have also become prominent in professional wrestling. There is also a less common role of a "tweener", who is neither fully face nor fully heel yet able to play either role effectively (case in point, Samoa Joe during his first run in Impact Wrestling from June 2005 to November 2006). At times, a character may "turn", altering their face/heel alignment. This may be an abrupt, surprising event, or it may slowly build over time. It is almost always accomplished with a markable change in behavior. Some turns become defining points in a career, as when Hulk Hogan turned heel after being a top face for over a decade. Others may have no noticeable effect on the character's status. If a character repeatedly switches between face and heel, this lessens the effect of such turns, and may result in apathy from the audience. Big Show is a good example of having more heel and face turns than anyone in WWE history. As with personae in general, a character's face or heel alignment may change with time, or remain constant over its lifetime (the most famous example of the latter is Ricky Steamboat, a WWE Hall of Famer who remained a babyface throughout his entire career). Sometimes a character's heel turn will become so popular that eventually the audience response will alter the character's heel-face cycle to the point where the heel persona will, in practice, become a face persona, and what was previously the face persona, will turn into the heel persona, such as when Dwayne Johnson first began using "The Rock" persona as a heel character, as opposed to his original "Rocky Maivia" babyface persona. Another legendary example is Stone Cold Steve Austin, who was originally booked as a heel, with such mannerisms as drinking on the job, using profanity, breaking company property, and even breaking into people's private homes. However, much to WWF's surprise, the fans response to Austin' was so positive that he effectively became one of the most popular antiheroes in professional wrestling. Austin, along with the stable of D-Generation X, Bret Hart and his Hart Foundation, is generally credited with ushering the Attitude Era of WWF programming. Story While real exhibition matches are now not uncommon, most matches tell a story analogous to an episode of a serial drama: the face will from time to time win (triumph) or from time to time lose (tragedy), and longer story arcs can result from a couple of matches. Since most promotions have a championship title, opposition for the championship is a frequent impetus for stories. For added stakes, anything from a character's own hair to his job can be wagered in a match. Some matches are designed to further the story of only one participant. It could be intended to portray an unstoppable force, a lucky underdog, a sore loser, or any other characterization. Sometimes non-wrestling vignettes are shown to enhance a character's image without the need for matches. Other stories result from a natural rivalry. Outside of performance, these are referred to as feuds. A feud can exist between any number of participants and can last from a few days to decades. The feud between Ric Flair and Ricky Steamboat lasted from the late 1970s into the early 1990s and allegedly spanned over two thousand matches (although most of those matches were mere dark matches). The career-spanning history between characters Mike Awesome and Masato Tanaka is another example of a long-running feud, as is the case of Steve Austin vs. Vince McMahon, one of the most lucrative feuds in the World Wrestling Federation during 1998 and 1999. In theory, the longer a feud is built up, the more audience interest (aka heat) lasts. The main event of a wrestling show is generally the most heated. Commonly, a heel will hold the upper hand over a face until a final showdown, heightening dramatic tension as the face's fans desire to see him win. Throughout the history of professional wrestling, many other elements of media have been utilized in professional wrestling storytelling: pre- and post-match interviews, "backstage" skits, positions of authority and worked behind-the-scenes feuds, division rankings (typically the #1-contendership spot), contracts, lotteries, news stories on websites, and in recent years social media. Also, anything that can be used as an element of drama can exist in professional wrestling stories: romantic relationships (including love triangles and marriage), racism, classism, nepotism, favoritism, corporate corruption, family bonds, personal histories, grudges, theft, cheating, assault, betrayal, bribery, seduction, stalking, confidence tricks, extortion, blackmail, substance abuse, self-doubt, self-sacrifice; even kidnapping, sexual fetishism, necrophilia, misogyny, rape and death have been portrayed in wrestling. Some promotions have included supernatural elements such as magic, curses, the undead and Satanic imagery (most notably the Undertaker and his Ministry of Darkness, a stable that regularly performed evil rituals and human sacrifice in Satanic-like worship of a hidden power figure). Celebrities would also be involved in storylines. Commentators have become important in communicating the relevance of the characters' actions to the story at hand, filling in past details and pointing out subtle actions that may otherwise go unnoticed. Promos A main part of the story-telling part of wrestling is a promo, short for promotional interview. Promos are performed, or "cut" in wrestling jargon, for a variety of reasons, including to heighten interest in a wrestler, or to hype an upcoming match. Since the crowd is often too loud or the venue too large for promos to be heard naturally, wrestlers will use amplification when speaking in the ring. Unlike most Hollywood acting, large and highly visible handheld microphones are typically used and wrestlers often speak directly to the audience. Championships Professional wrestling mimics the structure of title match combat sports. Participants compete for a championship and must defend it after winning it. These titles are represented physically by a title belt that can be worn by the champion. In the case of team wrestling, there is a title belt for each member of the team. Almost all professional wrestling promotions have one major title, and some have more. Championships are designated by divisions of weight, height, gender, wrestling style and other qualifications. Typically, each promotion only recognizes the "legitimacy" of their own titles, although cross-promotion does happen. When one promotion absorbs or purchases another, the titles from the defunct promotion may continue to be defended in the new promotion or be decommissioned. Behind the scenes, the bookers in a company will place the title on the most accomplished performer, or those the bookers believe will generate fan interest in terms of event attendance and television viewership. Historically, a world champion was typically a legit shooter/hooker who had the skills to prevent double crosses by would-be shooters who would deviate from the planned finish for personal glory. Lower ranked titles may also be used on the performers who show potential, thus allowing them greater exposure to the audience. However other circumstances may also determine the use of a championship. A combination of a championship's lineage, the caliber of performers as champion, and the frequency and manner of title changes, dictates the audience's perception of the title's quality, significance and reputation. A wrestler's championship accomplishments can be central to their career, becoming a measure of their performance ability and drawing power. In general, a wrestler with multiple title reigns or an extended title reign is indicative of a wrestler's ability to maintain audience interest or a wrestler's ability to perform in the ring. As such, the most accomplished or decorated wrestlers tend to be revered as legends due to the amount of title reigns they hold. American wrestler Ric Flair has had multiple world heavyweight championship reigns spanning over three decades. Japanese wrestler Último Dragón once held and defended a record 10 titles simultaneously. Non-standard matches Often a match will take place under additional rules, usually serving as a special attraction or a climactic point in a feud or storyline. Sometimes this will be the culmination of an entire feud, ending it for the immediate future (known as a blowoff match). Perhaps the most well-known non-standard match is the cage match, in which the ring is surrounded by a fence or similar metal structure, with the express intention of preventing escape or outside interference—and with the added bonus of the cage being a potentially brutal weapon or platform for launching attacks. The WWE has another provision where a standard cage match can end with one wrestler or wrestling team escaping the cage through the door or over the top. Another example is the WWE's Royal Rumble match, which involves thirty participants in a random and unknown order. The Rumble match is itself a spectacle in that it is a once-yearly event with multiple participants, including individuals who might not interact otherwise. It also serves as a catalyst for the company's ongoing feuds, as well as a springboard for new storylines. Ring entrance While the wrestling matches themselves are the primary focus of professional wrestling, a key dramatic element of the business can be entrances of the wrestlers to the arena and ring. It is typical for a wrestler to get their biggest crowd reaction (or "pop") for their ring entrance, rather than for anything they do in the wrestling match itself, especially if former main event stars are returning to a promotion after a long absence. All notable wrestlers now enter the ring accompanied by music, and regularly add other elements to their entrance. The music played during the ring entrance will usually mirror the wrestler's personality. Many wrestlers, particularly in America, have music and lyrics specially written for their ring entrance. While invented long before, the practice of including music with the entrance gained rapid popularity during the 1980s, largely as a result of the huge success of Hulk Hogan and the WWF, and their Rock 'n' Wrestling Connection. When a match is won, the victor's theme music is usually also played in celebration. Because wrestling is predetermined, a wrestler's entrance music will play as they enter the arena, even if they are, in kayfabe, not supposed to be there. For example, in 2012 through 2014, The Shield was a trio of wrestlers who were (in kayfabe) not at the time under contract with WWE (hence their gimmick of entering the ring through the crowd), but they still had entrance music which was played whenever they entered the arena, despite the fact that they were kayfabe invaders. With the introduction of the Titantron entrance screen in 1997, WWF/WWE wrestlers also had entrance videos made that would play along with their entrance music. Other dramatic elements of a ring entrance can include: Pyrotechnics such as a ring of fire for The Brood when they ascend to the stage, multi-colour fireworks (most notably for Edge), fire for Kane and Seth Rollins, a stage of smoke for Finn Bálor and (for a short period of time) falling fireworks for Christian Cage. Additional visual graphics or staging props to complement the entrance video/routine or further emphasize the character. For instance, Kane's entrance graphics employ heavy use of fire-themed visuals, The Undertaker's entrance features dark lighting, fire, fog and dry ice, and lightning-themed effects, John Morrison's entrance would feature use of multicolored psychedelic style patterns, The Miz has in the past incorporated inflatable lettering spelling out the word "AWESOME" into his entrance, and Montel Vontavious Porter frequently used an inflatable entrance tunnel during his WWE tenure. Goldust has been known to use on-screen visual effects in his entrance to simulate the presentation of a feature film (i.e. widescreen, production company credits), as to emphasize his Hollywood-themed film aficionado character. Brodus Clay entered with disco ball lighting effects to emphasize his "Funkasaurus" character. A distinct sound or opening note in the music (used to elicit a Pavlovian response from the crowd). For example, the glass shattering in Steve Austin's entrance theme, The Undertaker's signature bell toll, and the sound of bells and a cow's moo in JBL's theme. Darkening of the arena, often accompanied by mood lighting or strobe lighting, such as in The Undertaker's, Triple H's, or Sting's entrances. Certain colors of lighting have been associated with specific wrestlers; for instance, blue lighting for The Undertaker and Alexa Bliss, green lighting for Triple H, D-Generation X, and Shane McMahon, a mixture of red and yellow lighting for Brock Lesnar, a lot of red for Seth Rollins (mainly for his "Embrace The Vision" character, a.k.a when using his theme named "Visionary"), a mixture of red and orange lighting for Kane, multicolored lighting for John Morrison, gold lighting for Goldust, pink lighting for Val Venis and Trish Stratus, and so forth. Costumes that evoke "otherworldly" or "fictional" themes. With examples such as Big Van Vader's bio-mechanical themed headdress which spewed steam, Pyro's fire-shooting outfit, Shockmaster's bejeweled stormtrooper helmet, Ricky Steamboat's dragon costume and Mankind's leather mask, etc. Entering in a manner in keeping with their character traits, such as a fast, highly energetic entrance, or a slow, stoic entrance. For example, The Ultimate Warrior would run at high speed down the entrance ramp and into the ring while Randy Orton would walk slowly. The Undertaker has adopted one of the most notable entrances, taking around 4 to 5 minutes, darkening the whole arena, and performing a slow, intimidating walk. Goldberg walked slowly to the ring while being escorted by security guards from the locker room. Like sound effects, some entrance mannerisms often become signature to individual wrestlers. For example, Steve Austin's entrance often involves him standing on the second turnbuckle, raising his hands in the air for few seconds, and then doing the same thing for the other three turnbuckles, a mannerism which has become just as much a signature part of Austin's entrance as the glass-shattering sound effect. Driving a vehicle into the arena. For example, Eddie Guerrero would arrive into the arena in a lowrider, The Undertaker (in his "American Bad Ass" biker gimmick), Chuck Palumbo, Tara, and the Disciples of Apocalypse on motorcycles, The Mexicools on riding lawn mowers, JBL in his limousine, Alberto Del Rio arriving into the arena in various luxury cars, Steve Austin driving an all-terrain vehicle, and Camacho and Hunico entering on a lowrider bicycle. Acting out a trademark behavior, such as posing to display their muscularity, mounting the ring ropes, or sitting in the corner. Talking to the crowd using a distinctive patter. For instance, chanting or rapping along with the music (i.e. Road Dogg, R-Truth). Another example is Vickie Guerrero entering to no music, but announcing her arrival with the words "Excuse me!" Many heels with narcissistic gimmicks (Lex Luger, Shawn Michaels, Cody Rhodes, Paul Orndorff, etc.) would admire themselves in a mirror on their way to the ring. Coming through the audience, such as The Sandman's beer drinking and can smashing entrance, or Diamond Dallas Page's exit through the crowd, or Jon Moxley entering through the crowd. Accompaniment by a ringside crew or personal security, an example of which would be Goldberg. Entering the arena by a lift in the stage, such as Kurt Angle, The Brood and Rey Mysterio If a wrestler is a current champion, he will attempt to visually draw attention to his championship belt by either holding it high over his head or (if the belt is worn around the waist) moving his hands across it or pointing to it. Recently, Bobby Lashley has incorporated graphics and a dramatic opening into his entrance. The opening starts with lightning graphics hitting the stage, then going into a montage (for a short period of time, Lashley used parts of his entrance theme in the montage). Afterwards, graphics of him appear with the collective phrase "All Mighty" above his head, before switching to his entrance music. Another method of entry involves descending from the ceiling with a zip-line or rappel line and stunt harness. This has been done by Shawn Michaels at WrestleMania XII, by Sting many times in WCW and Impact and gained major controversy over its role in the death of wrestler Owen Hart at Over the Edge. Special ring entrances are also developed for big occasions, most notably the WrestleMania event. For example, WrestleMania III and VI both saw all wrestlers enter the arena on motorized miniature wrestling rings. Live bands are sometimes hired to perform live entrance music at special events. John Cena and Triple H are particularly notable in recent years for their highly theatrical entrances at WrestleMania. Other types of wrestling Women's wrestling The women's division of professional wrestling has maintained a recognized world champion since 1937, when Mildred Burke won the original World Women's title. She then formed the World Women's Wrestling Association in the early 1950s and recognized herself as the first champion, although the championship would be vacated upon her retirement in 1956. The NWA however, ceased to acknowledge Burke as the Women's World champion in 1954, and instead acknowledged June Byers as champion after a controversial finish to a high-profile match between Burke and Byers that year. Upon Byers's retirement in 1964, The Fabulous Moolah, who won a junior heavyweight version of the NWA World Women's Championship (the predecessor to the WWE Women's Championship) in a tournament back in 1958, was recognized by most NWA promoters as champion by default. Intergender wrestling For most of its history, men and women would rarely compete against each other in professional wrestling, as it was deemed to be unfair and unchivalrous. Andy Kaufman used this to gain notoriety when he created an Intergender Championship and declared it open to any female challenger. This led to a long (worked) feud with Jerry Lawler. In the 1980s, mixed tag team matches began to take place, with a male and female on each team and a rule stating that each wrestler could only attack the opponent of the same gender. If a tag was made, the other team had to automatically switch their legal wrestler as well. Despite these restrictions, many mixed tag matches do feature some physical interaction between participants of different genders. For example, a heel may take a cheap shot at the female wrestler of the opposing team to draw a negative crowd reaction. In lucha libre, cheap shots and male-female attacks are not uncommon. Intergender singles bouts were first fought on a national level in the 1990s. This began with Luna Vachon, who faced men in ECW and WWF. Later, Chyna became the first female to hold a belt that was not exclusive to women when she won the WWF Intercontinental Championship. Intergender wrestling was uncommon in Impact Wrestling. ODB, had participated in intergender matches and once held the Impact Knockouts Tag Team Championship with Eric Young for a record 478 days. Other notable Impact Knockouts that competed in intergender matches include Scarlett Bordeaux; Tessa Blanchard, who became the first woman to win the Impact World Championship; and Jordynne Grace, who became the inaugural Impact Digital Media Championship. Midget wrestling Midget wrestling can be traced to professional wrestling's carnival and vaudeville origins. In recent years, the popularity and prevalence of midgets in wrestling has greatly decreased due to wrestling companies depriving midget divisions of storyline or feud. However, WWE has made a few attempts to enter this market with their "minis" in the 1990s and the "junior's league" as recent as 2006. It is still a popular form of entertainment in Mexican wrestling, mostly as a "sideshow". Some wrestlers may have their own specific "mini me", like Mascarita Sagrada, Alebrije has Quije, etc. There are also cases in which midgets can become valets for a wrestler, and even get physically involved in matches, like Alushe, who often accompanies Tinieblas, or KeMonito, who is portrayed as Consejo Mundial de Lucha Libre's mascot and is also a valet for Mistico. Dave Finlay was often aided in his matches by a midget known mainly as Hornswoggle while in WWE, who hid under the ring and gave a shillelagh to Finlay to use on his opponent. Finlay also occasionally threw him at his opponents. Hornswoggle has also been given a run with the WWE Cruiserweight Championship and feuded with D-X in 2009. Styles and characteristics in other countries The U.S., Japan and Mexico are three countries where there is a huge market and high popularity for professional wrestling. But the styles of professional wrestling are different, given their independent development for a long period. Professional wrestling in the U.S. tends to have a heavy focus on story building and the establishment of characters (and their personalities). There is a story for each match, and even a longer story for successive matches. The stories usually contain characters like faces and heels, and less often antiheroes and tweeners. It is a "triumph" if the face wins, while it is a "tragedy" if the heel wins. The characters usually have strong and sharp personalities. The opposition between faces and heels is very intense in the story, and the heels may even attack the faces during TV interviews. The relationship between different characters can also be very complex. Although professional wrestling in Mexico (Lucha libre) also has stories and characters, they are less emphasized. Mexican professional wrestling tradition repeats very usually brutal tactics, specially more aerial holds than professional wrestlers in the U.S. who, more often, rely on power moves and strikes to subdue their opponents. The difference in styles is due to the independent evolution of the sport in Mexico beginning in the 1930s and the fact that wrestlers in the cruiserweight division () are often the most popular wrestlers in Mexican lucha libre. Wrestlers often execute high flying moves characteristic of lucha libre by utilizing the wrestling ring's ropes to catapult themselves towards their opponents, using intricate combinations in rapid-fire succession, and applying complex submission holds. Lucha libre is also known for its tag team wrestling matches, in which the teams are often made up of three members, instead of two as is common in the U.S. The style of Japanese professional wrestling (puroresu) is again different. With its origins in traditional American style of wrestling and still being under the same genre, it has become an entity in itself. Despite the similarity to its American counterpart in that the outcome of the matches remains predetermined, the phenomena are different in the form of the psychology and presentation of the sport. In most of the largest promotions, such as New Japan Pro-Wrestling, All Japan Pro Wrestling and Pro Wrestling Noah, it is treated as a full contact combat sport as it mixes hard hitting martial arts strikes with shoot style submission holds, while in the U.S. it is rather more regarded as an entertainment show. Wrestlers incorporate kicks and strikes from martial arts disciplines, and a strong emphasis is placed on submission wrestling, and unlike the use of involved storylines in the U.S., they are not as intricate in Japan, more emphasis is placed on the concept of "fighting spirit", meaning the wrestlers display of physical and mental stamina are valued a lot more than theatrics. Many of Japan's wrestlers including top stars such as Shinya Hashimoto, Riki Chōshū and Keiji Mutoh came from a legitimate martial arts background and many Japanese wrestlers in the 1990s began to pursue careers in mixed martial arts organizations such as Pancrase and Shooto which at the time retained the original look of puroresu but were actual competitions. Other companies, such as Michinoku Pro Wrestling and Dragon Gate, wrestle in a style similar to Mexican companies like AAA and CMLL. This is known as "Lucharesu". Culture Professional wrestling has developed its own cultures, both internal and external. Those involved in producing professional wrestling have developed a kind of global fraternity, with familial bonds, shared language and passed-down traditions. New performers are expected to "pay their dues" for a few years by working in lower-profile promotions and working as ring crew before working their way upward. The permanent rosters of most promotions develop a backstage pecking order, with veterans mediating conflicts and mentoring younger wrestlers. For many decades (and still to a lesser extent today) performers were expected to keep the illusions of wrestling's legitimacy alive even while not performing, essentially acting in character any time they were in public. Some veterans speak of a "sickness" among wrestling performers, an inexplicable pull to remain active in the wrestling world despite the devastating effects the job can have on one's life and health. Fans of professional wrestling have their own subculture, comparable to those of science fiction, video games, or comic books. Those who are interested in the backstage occurrences, future storylines and reasonings behind company decisions read newsletters written by journalists with inside ties to the wrestling industry. These "rags" or "dirt sheets" have expanded into the Internet, where their information can be dispensed on an up-to-the-minute basis. Some have expanded into radio shows. Some fans enjoy a pastime of collecting recordings of wrestling shows from specific companies, of certain wrestlers, or of specific genres. The internet has given fans exposure to worldwide variations of wrestling they would be unable to see otherwise. Since the 1990s, many companies have been founded which deal primarily in wrestling footage. When the WWE purchased both WCW and ECW in 2001, they also obtained the entire past video libraries of both productions and have released many past matches online and on home video. Like some other sports, fantasy leagues have developed around professional wrestling. Some take this concept further by creating E-feds (electronic federations), where a user can create their own fictional wrestling character, and role-playing storylines with other users, leading to scheduled "shows" where match results are determined by the organizers, usually based on a combination of the characters' statistics and the players' roleplaying aptitude, sometimes with audience voting. Professional wrestling in mainstream culture From the first established world championship, the top professional wrestlers have garnered fame within mainstream society. Each successive generation has produced a number of wrestlers who extend their careers into the realms of music, acting, writing, business, politics or public speaking, and are known to those who are unfamiliar with wrestling in general. Conversely, celebrities from other sports or general pop culture also become involved with wrestling for brief periods of time. A prime example of this is The Rock 'n' Wrestling Connection of the 1980s, which combined wrestling with MTV. Professional wrestling is often portrayed within other works using parody, and its general elements have become familiar tropes and memes in American culture. Some terminology originating in professional wrestling has found its way into the common vernacular. Phrases such as "body slam", "sleeper hold" and "tag team" are used by those who do not follow professional wrestling. The term "smackdown", popularized by The Rock and SmackDown! in the 1990s, has been included in Merriam-Webster dictionaries since 2007. Many television shows and films have been produced which portray in-character professional wrestlers as protagonists, such as Ready to Rumble, ¡Mucha Lucha!,	both members on the outside at any given time. In these matches, tags can be made between any two teams regardless if they are on the same team or not. As a result of this stipulation, tags between different teams are not usually mutual effort; a non-legal wrestler will usually tag themselves in against the legal wrestler's will. A legal wrestler will only voluntarily tag themselves out to another team if their own partner is incapacitated, or are being held in a submission hold and are closer to another tag team than their own. Sometimes, poly-sided matches that pit every man for himself will incorporate tagging rules. Outside of kayfabe, this is done to give wrestlers a break from the action (as these matches tend to go on for long periods of time), and to make the action in the ring easier to choreograph. One of the most mainstream examples of this is the Four-Corner match, the most common type of match in the WWE before it was replaced with its equivalent Fatal Four-Way; four wrestlers, each for himself, fight in a match, but only two wrestlers can be in the match at any given time. The other two are positioned in the corner, and tags can be made between any two wrestlers. In a Texas Tornado Tag Team match, all the competitors are legal in the match, and tagging in and out is not necessary. All matches fought under hardcore rules (such as no disqualification, no holds barred, ladder match, etc.) are all contested under de facto Texas Tornado rules, since the lack of ability of a referee to issue a disqualification renders any tagging requirements moot. Regardless of rules of tagging, a wrestler cannot pin his or her own tag team partner, even if it is technically possible from the rules of the match (e.g. Texas Tornado rules, or a three-way tag team match). This is called the "Outlaw Rule" because the first team to attempt to use that (in an attempt to unfairly retain their tag team titles) was the New Age Outlaws. Decisions Pinfall To score by pinfall, a wrestler must pin both his opponent's shoulders against the mat while the referee slaps the mat three times (referred to as a "three count"). This is the most common form of defeat. The pinned wrestler must also be on his back and, if they're lying on his stomach, it usually does not count. A count may be started at any time that a wrestler's shoulders are down (both shoulders touching the mat), back-first and any part of the opponent's body is lying over the wrestler. This often results in pins that can easily be kicked out of, if the defensive wrestler is even slightly conscious. For example, an attacking wrestler who is half-conscious may simply drape an arm over an opponent, or a cocky wrestler may place his foot gently on the opponent's body, prompting a three-count from the referee. Illegal pinning methods include using the ropes for leverage and hooking the opponent's clothing, which are therefore popular cheating methods for heels, unless certain stipulations make such an advantage legal. Pins such as these are rarely seen by the referee and are subsequently often used by heels and on occasion by cheating faces to win matches. Even if it is noticed, it is rare for such an attempt to result in a disqualification (see below) and instead it simply results in nullification of the pin attempt, so the heel wrestler rarely has anything to lose for trying it anyway. Occasionally, there are instances where a pinfall is made where both wrestlers' shoulders were on the mat for the three-count. This situation will most likely lead to a draw, and in some cases a continuation of the match or a future match to determine the winner. Submission To score by submission, the wrestler must make his opponent give up, usually, but not necessarily, by putting him in a submission hold (e.g. figure four leg-lock, arm-lock, sleeper-hold). A wrestler may voluntarily submit by verbally informing the referee (usually used in moves such as the Mexican Surfboard, where all four limbs are incapacitated, making tapping impossible). Also, since Ken Shamrock popularized it in 1997, a wrestler can indicate a voluntary submission by "tapping out", that is, tapping a free hand against the mat or against an opponent. Occasionally, a wrestler will reach for a rope (see rope breaks below), only to put his hand back on the mat so he can crawl towards the rope some more; this is not a submission, and the referee decides what his intent is. Submission was initially a large factor in professional wrestling, but following the decline of the submission-oriented catch-as-catch-can style from mainstream professional wrestling, the submission largely faded. Despite this, some wrestlers, such as Chris Jericho, Ric Flair, Bret Hart, Kurt Angle, Ken Shamrock, Dean Malenko, Chris Benoit, and Tazz, became famous for winning matches via submission. A wrestler with a signature submission technique is portrayed as better at applying the hold, making it more painful or more difficult to get out of than others who use it, or can be falsely credited as inventing the hold (such as when Tazz popularized the kata ha jime judo choke in pro wrestling as the "Tazzmission"). Since all contact between the wrestlers must cease if any part of the body is touching, or underneath, the ropes, many wrestlers will attempt to break submission holds by deliberately grabbing the bottom ropes. This is called a "rope break", and it is one of the most common ways to break a submission hold. Most holds leave an arm or leg free, so that the person can tap out if he wants. Instead, he uses these free limbs to either grab one of the ring ropes (the bottom one is the most common, as it is nearest the wrestlers, though other ropes sometimes are used for standing holds such as Chris Masters's Master Lock) or drape his foot across, or underneath one. Once this has been accomplished, and witnessed by the referee, the referee will demand that the offending wrestler break the hold, and start counting to five if the wrestler does not. If the referee reaches the count of five, and the wrestler still does not break the hold, he is disqualified. If a manager decides that his client wrestler should tap out, but cannot convince the wrestler himself to do so, he may "throw in the towel" (by literally taking a gym towel and hurling it into the ring where the referee can see it). This is the same as a submission, as in kayfabe the manager is considered the wrestlers agent and therefore authorized to make formal decisions (such as forfeiting a match) on the client's behalf. Knockout Passing out in a submission hold constitutes a loss by technical knockout. To determine if a wrestler has passed out in WWE, the referee usually picks up and drops his hand. If it drops to the mat or floor one or three consecutive times without the wrestler having the strength to hold it up, the wrestler is considered to have passed out. At one point this was largely ignored. However, the rule is now much more commonly observed for safety reasons. If the wrestler has passed out, the opponent then has won by technical knockout or technical submission. A wrestler can also win by technical knockout even if he does not resort to submission holds, but still attacks the opponent to the point of unconsciousness. To check for a technical knockout in this manner a referee would wave his hand in front of the wrestler's face and, if this produces no reaction of any kind, the referee would award the victory to the other wrestler. Countout A countout (alternatively "count-out" or "count out") happens when a wrestler is out of the ring long enough for the referee to count to ten (twenty in some promotions) and thus disqualified. The count is broken and restarted when a wrestler in the ring exits the ring. Playing into this, some wrestlers would "milk" the count by sliding in the ring and immediately sliding back out. As he was technically inside the ring for a split second before exiting again, it is sufficient to restart the count. This is often referred to by commentators as "breaking the count". Heels often use this tactic in order to buy themselves more time to catch their breath, or to attempt to frustrate their babyface opponents. If all the active wrestlers in a match are down inside the ring at the same time, the referee would begin a count (usually ten seconds, twenty in Japan). If nobody rises to their feet by the end of the count, the match is ruled a draw. Any participant who stands up in time would end the count for everyone else, while in a Last Man Standing match this form of a countout is the only way that the match can end, so the referee would count when one or more wrestlers are down and one wrestler standing up before the 10-count does not stop the count for another wrestler who is still down. In some promotions (and most major modern ones), Championships cannot change hands via a countout, unless the on-screen authority declares it for at least one match, although in others, championships may change hands via countout. Heels are known to take advantage of this and will intentionally get counted out when facing difficult opponents, especially when defending championships. Disqualification Disqualification (sometimes abbreviated as "DQ") occurs when a wrestler violates the match's rules, thus losing automatically. Although a countout can technically be considered a disqualification (as it is, for all intents and purposes, an automatic loss suffered as a result of violating a match rule), the two concepts are often distinct in wrestling. A no disqualification match can still end by countout (although this is rare). Typically, a match must be declared a "no holds barred" match, a "street fight" or some other term, in order for both disqualifications and countouts to be waived. Disqualification from a match is called for a number of reasons: Performing any illegal holds or maneuvers, such as refusing to break a hold when an opponent is in the ropes, hair-pulling, choking or biting an opponent, or repeatedly punching with a closed fist. These violations are usually subject to a referee-administered five count and will result in disqualification if the wrestler does not cease the offending behavior in time. Note that the ban on closed fists does not apply if the attacker is in midair when the punch connects, like with Jerry Lawler's diving fist drop or Roman Reigns's Superman Punch. Deliberate injury of an opponent, such as attacking an opponent's eye, such as raking it, poking it, gouging it, punching it or other severe attacks to the eye. This was imposed when Sexy Star was disqualified for a legitimate injury on Rosemary at AAA Triplemanía XXV by popping her arm out of the socket. This type of disqualification can also be grounds for stripping a wrestler of a championship, as AAA overturned the result of that AAA Women's Championship match, stripping her of the title. Any outside interference involving a person not involved in the match striking or holding a wrestler. Sometimes (depending on the promotion and uniqueness of the situation), if a heel attempts to interfere but is ejected from the ring by a wrestler or referee before this occurs, there may not be a disqualification (All Elite Wrestling is known to use ejections, as AEW referees Earl Hebner and Aubrey Edwards have ejected numerous wrestlers during events, all for outside interference). In this disqualification method, the wrestler being attacked by the foreign member is awarded the win. Sometimes, however, this can work in heels' favor. In February 2009, Shawn Michaels, who was under the kayfabe employment of John "Bradshaw" Layfield, interfered in a match and super kicked JBL in front of the referee to get his employer the win via "outside interference". Striking an opponent with a foreign object (an object not permitted by the rules of the match; see hardcore wrestling). Sometimes the win decision can be reversed if the referee spots the weapon before pin attempt or after the match because a wrestler tried to strike when the referee was either distracted or knocked out. Using any kind of "banned" move (see below for details). A direct low blow to the groin (unless the rules of the match specifically allow this). Intentionally laying hands on the referee. Pulling an opponent's mask off during a match (this is illegal in Mexico, and sometimes in Japan). Throwing an opponent over the top rope during a match (this move is still illegal in the National Wrestling Alliance; however, in cases like the Royal Rumble match, this will be allowed in order to eliminate a wrestler from the match). In a mixed tag team match, a male wrestler hitting a female wrestler (intergender), or a normal sized wrestler attacking an opposing midget wrestler (tag team matches involving teams with one normal-sized and one midget wrestler). In practice, not all rule violations will result in a disqualification as the referee may use his own judgement and is not obligated to stop the match. Usually, the only offenses that the referee will see and immediately disqualify a wrestler for (as opposed to having multiple offenses) are low blows, weapon usage, interference, or assaulting the referee. In WWE, a referee must see the violation with his own eyes to rule that the match end in a disqualification (simply watching the video tape is usually not enough) and the referee's ruling is almost always final, although dusty finishes (named after, and made famous by, Dusty Rhodes) will often result in the referee's decision being overturned. It is not uncommon for the referees themselves to get knocked out during a match, which is commonly referred to by the term "ref bump". While the referee remains "unconscious", wrestlers are free to violate rules until he is revived or replaced. In some cases, a referee might disqualify a person under the presumption that it was that wrestler who knocked him out; most referee knockouts are arranged to allow a wrestler, usually a heel, to gain an advantage. For example, a wrestler may get whipped into a referee at a slower speed, knocking the ref down for short amount of time; during that interim period, one wrestler may pin his opponent for a three-count and would have won the match but for the referee being down (sometimes, another referee will sprint to the ring from backstage to attempt to make the count, but by then, the other wrestler has had enough time to kick out on his own accord). In most promotions, a championship title cannot normally change hands via disqualification; this rule is explicitly enforced in a title match under special circumstances. If all participants in a match continue to breach the referee's instructions, the match may end in a double disqualification, where both wrestlers or teams (in a tag team match) have been disqualified. The match is essentially nullified, and called a draw or in some cases a restart or the same match being held at a pay-per-view or next night's show. Sometimes, however, if this happens in a match to determine the challenger for a heel champion's title, the champion is forced to face both opponents simultaneously for the title. Usually, the double disqualification is caused by the heel wrestler's associates in a match between two face wrestlers to determine his opponent. Forfeit Although extremely rare, a match can end in a forfeit if the opponent either does not show up for the match, or shows up but refuses to compete. Although a championship usually cannot change hands except by pinfall or submission, a forfeit victory is enough to crown a new champion. A famous example of this happened on the December 8, 1997 episode of Raw is War, when Stone Cold Steve Austin handed the WWE Intercontinental Championship to The Rock after refusing to defend the title. When a pay-per-view match is booked and one wrestler is unable to make it for one reason or another, it is usually customary to insert a last minute replacement rather than award a wrestler a victory by forfeit. Forfeit victories are almost always reserved for when the story the promotion is telling specifically requires such an ending. Despite being, statistically, an extremely rare occurrence, Charles Wright is one wrestler who is famous for turning forfeit victories into his own gimmick. During the late 1990s, Wright called himself "The Godfather" and portrayed the gimmick of a pimp. He would often bring multiple women, who he referred to as "hos," to the ring with him, and would offer the sexual services of these women to his opponents in exchange for them forfeiting their matches against him. Draw A professional wrestling match can end in a draw. A draw occurs if both opponents are simultaneously disqualified (as via countout or if the referee loses complete control of the match and both opponents attack each other with no regard to being in a match, like Brock Lesnar vs. Undertaker at 2002 Unforgiven), neither opponent is able to answer a ten-count, or both opponents simultaneously win the match. The latter can occur if, for example, one opponent's shoulders touch the mat while maintaining a submission hold against another opponent. If the opponent in the hold begins to tap out at the same time a referee counts to three for pinning the opponent delivering the hold, both opponents have legally achieved scoring conditions simultaneously. Traditionally, a championship may not change hands in the event of a draw (though it may become vacant), though some promotions such as Impact Wrestling (formally Total Nonstop Action (TNA) Wrestling) have endorsed rules where the champion may lose a title by disqualification. A variant of the draw is the time-limit draw, where the match does not have a winner by a specified time period (a one-hour draw, which was once common, is known in wrestling circles as a "Broadway"). Also if two wrestlers have been given a disqualification by either the referee or the chairman, this is a no contest and if there is a title on the line the champion keeps the championship. No contest A wrestling match may be declared a no contest if the winning conditions are unable to occur. This can be due to excessive interference, loss of referee's control over the match, one or more participants sustaining debilitating injury not caused by the opponent, or the inability of a scheduled match to even begin. A no contest is a state separate and distinct from a draw — a draw indicates winning conditions were met. Although the terms are sometimes used interchangeably in practice, this usage is technically incorrect. Dramatic elements While each wrestling match is ostensibly a competition of athletics and strategy, the goal from a business standpoint is to excite and entertain the audience. Although the competition is staged, dramatic emphasis draws out the most intense reaction. Heightened interest results in higher attendance, increased ticket sales, higher ratings on television broadcasts (greater ad revenue), higher pay-per-view buyrates, and sales of branded merchandise and recorded video footage. All of these contribute to the profit of the promotion company. Character/gimmick In Latin America and English-speaking countries, most wrestlers (and other on-stage performers) portray character roles, sometimes with personalities wildly different from their own. These personalities are a gimmick intended to heighten interest in a wrestler without regard to athletic ability. Some can be unrealistic and cartoon-like (such as Doink the Clown), while others carry more verisimilitude (such as Chris Jericho, The Rock, John Cena, Steve Austin, and CM Punk). In lucha libre, many characters wear masks, adopting a secret identity akin to a superhero or a supervillain, a near-sacred tradition. An individual wrestler may use his real name, or a minor variation of it, for much of his career, such as Bret Hart, John Cena and Randy Orton. Others can keep one ring name for their entire career (Shawn Michaels, CM Punk and Ricky Steamboat), or may change from time to time to better suit the demands of the audience or company. Sometimes a character is owned and trademarked by the company, forcing the wrestler to find a new one when he leaves (although a simple typeset change, such as changing Rhyno to Rhino, can get around this), and sometimes a character is owned by the wrestler. Sometimes, a wrestler may change his legal name to obtain ownership of his ring name (Andrew Martin and Warrior). Many wrestlers (such as The Rock and The Undertaker) are strongly identified with their character, even responding to the name in public or between friends. It's actually considered proper decorum for fellow wrestlers to refer to each other by their stage names/characters rather than their birth/legal names, unless otherwise introduced. A character can become so popular that it appears in other media (Hulk Hogan and El Santo) or even gives the performer enough visibility to enter politics (Antonio Inoki and Jesse Ventura). Typically, matches are staged between a protagonist (historically an audience favorite, known as a babyface, or "the good guy") and an antagonist (historically a villain with arrogance, a tendency to break rules, or other unlikable qualities, called a heel, or "the bad guy"). In recent years, however, antiheroes have also become prominent in professional wrestling. There is also a less common role of a "tweener", who is neither fully face nor fully heel yet able to play either role effectively (case in point, Samoa Joe during his first run in Impact Wrestling from June 2005 to November 2006). At times, a character may "turn", altering their face/heel alignment. This may be an abrupt, surprising event, or it may slowly build over time. It is almost always accomplished with a markable change in behavior. Some turns become defining points in a career, as when Hulk Hogan turned heel after being a top face for over a decade. Others may have no noticeable effect on the character's status. If a character repeatedly switches between face and heel, this lessens the effect of such turns, and may result in apathy from the audience. Big Show is a good example of having more heel and face turns than anyone in WWE history. As with personae in general, a character's face or heel alignment may change with time, or remain constant over its lifetime (the most famous example of the latter is Ricky Steamboat, a WWE Hall of Famer who remained a babyface throughout his entire career). Sometimes a character's heel turn will become so popular that eventually the audience response will alter the character's heel-face cycle to the point where the heel persona will, in practice, become a face persona, and what was previously the face persona, will turn into the heel persona, such as when Dwayne Johnson first began using "The Rock" persona as a heel character, as opposed to his original "Rocky Maivia" babyface persona. Another legendary example is Stone Cold Steve Austin, who was originally booked as a heel, with such mannerisms as drinking on the job, using profanity, breaking company property, and even breaking into people's private homes. However, much to WWF's surprise, the fans response to Austin' was so positive that he effectively became one of the most popular antiheroes in professional wrestling. Austin, along with the stable of D-Generation X, Bret Hart and his Hart Foundation, is generally credited with ushering the Attitude Era of WWF programming. Story While real exhibition matches are now not uncommon, most matches tell a story analogous to an episode of a serial drama: the face will from time to time win (triumph) or from time to time lose (tragedy), and longer story arcs can result from a couple of matches. Since most promotions have a championship title, opposition for the championship is a frequent impetus for stories. For added stakes, anything from a character's own hair to his job can be wagered in a match. Some matches are designed to further the story of only one participant. It could be intended to portray an unstoppable force, a lucky underdog, a sore loser, or any other characterization. Sometimes non-wrestling vignettes are shown to enhance a character's image without the need for matches. Other stories result from a natural rivalry. Outside of performance, these are referred to as feuds. A feud can exist between any number of participants and can last from a few days to decades. The feud between Ric Flair and Ricky Steamboat lasted from the late 1970s into the early 1990s and allegedly spanned over two thousand matches (although most of those matches were mere dark matches). The career-spanning history between characters Mike Awesome and Masato Tanaka is another example of a long-running feud, as is the case of Steve Austin vs. Vince McMahon, one of the most lucrative feuds in the World Wrestling Federation during 1998 and 1999. In theory, the longer a feud is built up, the more audience interest (aka heat) lasts. The main event of a wrestling show is generally the most heated. Commonly, a heel will hold the upper hand over a face until a final showdown, heightening dramatic tension as the face's fans desire to see him win. Throughout the history of professional wrestling, many other elements of media have been utilized in professional wrestling storytelling: pre- and post-match interviews, "backstage" skits, positions of authority and worked behind-the-scenes feuds, division rankings (typically the #1-contendership spot), contracts, lotteries, news stories on websites, and in recent years social media. Also, anything that can be used as an element of drama can exist in professional wrestling stories: romantic relationships (including love triangles and marriage), racism, classism, nepotism, favoritism, corporate corruption, family bonds, personal histories, grudges, theft, cheating, assault, betrayal, bribery, seduction, stalking, confidence tricks, extortion, blackmail, substance abuse, self-doubt, self-sacrifice; even kidnapping, sexual fetishism, necrophilia, misogyny, rape and death have been portrayed in wrestling. Some promotions have included supernatural elements such as magic, curses, the undead and Satanic imagery (most notably the Undertaker and his Ministry of Darkness, a stable that regularly performed evil rituals and human sacrifice in Satanic-like worship of a hidden power figure). Celebrities would also be involved in storylines. Commentators have become important in communicating the relevance of the characters' actions to the story at hand, filling in past details and pointing out subtle actions that may otherwise go unnoticed. Promos A main part of the story-telling part of wrestling is a promo, short for promotional interview. Promos are performed, or "cut" in wrestling jargon, for a variety of reasons, including to heighten interest in a wrestler, or to hype an upcoming match. Since the crowd is often too loud or the venue too large for promos to be heard naturally, wrestlers will use amplification when speaking in the ring. Unlike most Hollywood acting, large and highly visible handheld microphones are typically used and wrestlers often speak directly to the audience. Championships Professional wrestling mimics the structure of title match combat sports. Participants compete for a championship and must defend it after winning it. These titles are represented physically by a title belt that can be worn by the champion. In the case of team wrestling, there is a title belt for each member of the team. Almost all professional wrestling promotions have one major title, and some have more. Championships are designated by divisions of weight, height, gender, wrestling style and other qualifications. Typically, each promotion only recognizes the "legitimacy" of their own titles, although cross-promotion does happen. When one promotion absorbs or purchases another, the titles from the defunct promotion may continue to be defended in the new promotion or be decommissioned. Behind the scenes, the bookers in a company will place the title on the most accomplished performer, or those the bookers believe will generate fan interest in terms of event attendance and television viewership. Historically, a world champion was typically a legit shooter/hooker who had the skills to prevent double crosses by would-be shooters who would deviate from the planned finish for personal glory. Lower ranked titles may also be used on the performers who show potential, thus allowing them greater exposure to the audience. However other circumstances may also determine the use of a championship. A combination of a championship's lineage, the caliber of performers as
a pure state, in polar coordinates, , the idempotent density matrix acts on the state eigenvector with eigenvalue +1, hence it acts like a projection operator. Relation with the permutation operator Let be the transposition (also known as a permutation) between two spins and living in the tensor product space This operator can also be written more explicitly as Dirac's spin exchange operator, Its eigenvalues are therefore 1 or −1. It may thus be utilized as an interaction term in a Hamiltonian, splitting the energy eigenvalues of its symmetric versus antisymmetric eigenstates. SU(2) The group SU(2) is the Lie group of unitary matrices with unit determinant; its Lie algebra is the set of all anti-Hermitian matrices with trace 0. Direct calculation, as above, shows that the Lie algebra is the 3-dimensional real algebra spanned by the set . In compact notation, As a result, each can be seen as an infinitesimal generator of SU(2). The elements of SU(2) are exponentials of linear combinations of these three generators, and multiply as indicated above in discussing the Pauli vector. Although this suffices to generate SU(2), it is not a proper representation of , as the Pauli eigenvalues are scaled unconventionally. The conventional normalization is so that As SU(2) is a compact group, its Cartan decomposition is trivial. SO(3) The Lie algebra is isomorphic to the Lie algebra , which corresponds to the Lie group SO(3), the group of rotations in three-dimensional space. In other words, one can say that the are a realization (and, in fact, the lowest-dimensional realization) of infinitesimal rotations in three-dimensional space. However, even though and are isomorphic as Lie algebras, and are not isomorphic as Lie groups. is actually a double cover of , meaning that there is a two-to-one group homomorphism from to , see relationship between SO(3) and SU(2). Quaternions The real linear span of is isomorphic to the real algebra of quaternions , represented by the span of the basis vectors The isomorphism from to this set is given by the following map (notice the reversed signs for the Pauli matrices): Alternatively, the isomorphism can be achieved by a map using the Pauli matrices in reversed order, As the set of versors forms a group isomorphic to , gives yet another way of describing . The two-to-one homomorphism from to may be given in terms of the Pauli matrices in this formulation. Physics Classical mechanics In classical mechanics, Pauli matrices are useful in the context of the Cayley-Klein parameters. The matrix corresponding to the position of a point in space is defined in terms of the above Pauli vector matrix, Consequently, the transformation matrix for rotations about the -axis through an angle may be written in terms of Pauli matrices and the unit matrix as Similar expressions follow for general Pauli vector rotations as detailed above. Quantum mechanics In quantum mechanics, each Pauli matrix is related to an angular momentum operator that corresponds to an observable describing the spin of a spin particle, in each of the three spatial directions. As an immediate consequence of the Cartan decomposition mentioned above, are the generators of a projective representation (spin representation) of the rotation group SO(3) acting on non-relativistic particles with spin . The states of the particles are represented as two-component spinors. In the same way, the Pauli matrices are related to the isospin operator. An interesting property of spin particles is that they must be rotated by an angle of 4 in order to return to their original configuration. This is due to the two-to-one correspondence between SU(2) and SO(3) mentioned above, and the fact that, although one visualizes spin up/down as the north/south pole on the 2-sphere they are actually represented by orthogonal vectors in the two dimensional complex Hilbert space. For a spin particle, the spin operator is given by , the fundamental representation of SU(2). By taking Kronecker products of this representation with itself repeatedly, one may construct all higher irreducible representations. That is, the resulting spin operators for higher spin systems in three spatial dimensions, for arbitrarily large j, can be calculated using this spin operator and ladder operators. They can be found in . The analog formula to the above generalization of Euler's formula for Pauli matrices, the group element in terms of spin matrices, is tractable, but less simple. Also useful in the quantum mechanics of multiparticle systems, the general Pauli group is defined to consist of all -fold	the Pauli vector, namely rotation effectively by double the angle , Completeness relation An alternative notation that is commonly used for the Pauli matrices is to write the vector index in the superscript, and the matrix indices as subscripts, so that the element in row and column of the -th Pauli matrix is In this notation, the completeness relation for the Pauli matrices can be written Proof: The fact that the Pauli matrices, along with the identity matrix , form an orthogonal basis for the Hilbert space of all 2 × 2 complex matrices means that we can express any matrix as where is a complex number, and is a 3-component, complex vector. It is straightforward to show, using the properties listed above, that where "" denotes the trace, and hence that which can be rewritten in terms of matrix indices as where summation over the repeated indices is implied and . Since this is true for any choice of the matrix , the completeness relation follows as stated above. As noted above, it is common to denote the 2 × 2 unit matrix by so The completeness relation can alternatively be expressed as The fact that any Hermitian complex 2 × 2 matrices can be expressed in terms of the identity matrix and the Pauli matrices also leads to the Bloch sphere representation of 2 × 2 mixed states’ density matrix, (positive semidefinite 2 × 2 matrices with unit trace. This can be seen by first expressing an arbitrary Hermitian matrix as a real linear combination of as above, and then imposing the positive-semidefinite and trace conditions. For a pure state, in polar coordinates, , the idempotent density matrix acts on the state eigenvector with eigenvalue +1, hence it acts like a projection operator. Relation with the permutation operator Let be the transposition (also known as a permutation) between two spins and living in the tensor product space This operator can also be written more explicitly as Dirac's spin exchange operator, Its eigenvalues are therefore 1 or −1. It may thus be utilized as an interaction term in a Hamiltonian, splitting the energy eigenvalues of its symmetric versus antisymmetric eigenstates. SU(2) The group SU(2) is the Lie group of unitary matrices with unit determinant; its Lie algebra is the set of all anti-Hermitian matrices with trace 0. Direct calculation, as above, shows that the Lie algebra is the 3-dimensional real algebra spanned by the set . In compact notation, As a result, each can be seen as an infinitesimal generator of SU(2). The elements of SU(2) are exponentials of linear combinations of these three generators, and multiply as indicated above in discussing the Pauli vector. Although this suffices to generate SU(2), it is not a proper representation of , as the Pauli eigenvalues are scaled unconventionally. The conventional normalization is so that As SU(2) is a compact group, its Cartan decomposition is trivial. SO(3) The Lie algebra is isomorphic to the Lie algebra , which corresponds to the Lie group SO(3), the group of rotations in three-dimensional space. In other words, one can say that the are a realization (and, in fact, the lowest-dimensional realization) of infinitesimal rotations in three-dimensional space. However, even though and are isomorphic as Lie algebras, and are not isomorphic as Lie groups. is actually a double cover of , meaning that there is a two-to-one group homomorphism from to , see relationship between SO(3) and SU(2). Quaternions The real linear span of is isomorphic to the real algebra of quaternions , represented by the span of the basis vectors The isomorphism from to this set is given by the following map (notice the reversed signs for the Pauli matrices): Alternatively, the isomorphism can be achieved by a map using the Pauli matrices in reversed order, As the set of versors forms a group isomorphic to , gives yet another way of describing . The two-to-one homomorphism from to may be given in terms of the Pauli matrices in this formulation. Physics Classical mechanics In classical mechanics, Pauli matrices are useful in the context of the Cayley-Klein parameters. The matrix corresponding to the position of a point in space is defined in terms of the above Pauli vector matrix, Consequently, the transformation matrix for rotations about the -axis through an angle may be written in terms of Pauli matrices and the unit matrix as Similar expressions follow for general Pauli vector rotations as detailed above. Quantum mechanics In quantum mechanics, each Pauli matrix is related to an angular momentum operator that corresponds to an observable describing the spin of a spin particle, in each of the three spatial directions. As an immediate consequence of the Cartan decomposition mentioned above, are the generators of a projective representation (spin representation) of the rotation group SO(3) acting on non-relativistic particles with spin .
inactive center and works best with stylus input, and well with a mouse. Pie slices are drawn with a hole in the middle for an easy way to exit the menu. Pie menus work well with keyboard acceleration, particularly four and eight item menus, on the cursor keys and the number pad. A goal of pie menus is to provide a smooth, reliable gestural style of interaction for novices and experts. A slice can lead to another pie menu; selecting this may center the pointer in the new menu. A marking menu is a variant of this technique that makes the menu less sensitive to variance in gesture size. As a kind of context menu, pie menus are often context-sensitive, showing different options depending on what the pointer was pointing at when the menu was requested. History The first documented radial menu is attributed to a system called PIXIE in 1969. Some universities explored alternative visual layouts. In 1986, Mike Gallaher and Don Hopkins together independently arrived at the concept of a context menu based on the angle to the origin where the exact angle and radius could be passed as parameters to a command, and a mouse click could be used to trigger an item or submenu. The first performance comparison to linear menus was performed in 1988 showing an increase in performance of 15% less time and a reduction of selection errors. The role-playing video game Secret of Mana featured an innovative icon-based radial menu system in 1993. Its ring menu system was adopted by later video games. Usage For novice users, pie menus are easy because they are a self-revealing gestural interface: They show what you can do and direct you how to do it. By clicking and popping up a pie menu, looking at the labels, moving the pointer in the desired direction, then clicking to make a selection, users learn the menu and practice the gesture to "mark ahead" ("mouse ahead" in the case of a mouse, "wave ahead" in the case of a dataglove). With a little practice, it becomes quite easy to mark ahead even through nested pie menus. For the expert, the pie menus are more efficient. Because they might have built up the muscle memory for certain menu actions, and able to select the option they want without looking the pop up selections. In some cases, only when used more slowly like a traditional menu, does a pie menu pop up on the screen, to reveal the available selections. Moreover, novices can gradually become experts when they practice the same pie menu selection for many times and start to remember the menu and the motion. As Jaron Lanier of VPL Research has remarked, "The mind may forget, but the body remembers." Pie menus take advantage of the body's ability to remember muscle motion and direction, even when the mind has forgotten the corresponding symbolic labels. Comparison with other interaction techniques Pie menus are faster and more reliable to select from than linear menus, because selection depends on direction instead of distance. The circular menu slices are large in size and near the pointer for fast interaction (see Fitts's law). Experienced users use muscle memory without looking at the menu while selecting from it. Nested pie menus can efficiently offer many options, and some pie menus can pop up linear menus, and combine linear and radial items in the same menu. Pie menus just like any popup menu are shown only when requested, resulting in less visual distraction and cognitive load than toolbars and menu bars that are always shown. Pie menus show available options, in contrast to invisible mouse gestures. Pie menus, which delay appearance until the pointer is not moving, reduce intrusiveness to the same level as mouse gestures for experienced users. Pie menus take up more screen space than linear menus, and the number of slices in an individual menu must be kept low for effectiveness by using submenus. When using pie menus, submenus may overlap with the parent menu, but the parent menu may become translucent or hidden. Pie menus	even through nested pie menus. For the expert, the pie menus are more efficient. Because they might have built up the muscle memory for certain menu actions, and able to select the option they want without looking the pop up selections. In some cases, only when used more slowly like a traditional menu, does a pie menu pop up on the screen, to reveal the available selections. Moreover, novices can gradually become experts when they practice the same pie menu selection for many times and start to remember the menu and the motion. As Jaron Lanier of VPL Research has remarked, "The mind may forget, but the body remembers." Pie menus take advantage of the body's ability to remember muscle motion and direction, even when the mind has forgotten the corresponding symbolic labels. Comparison with other interaction techniques Pie menus are faster and more reliable to select from than linear menus, because selection depends on direction instead of distance. The circular menu slices are large in size and near the pointer for fast interaction (see Fitts's law). Experienced users use muscle memory without looking at the menu while selecting from it. Nested pie menus can efficiently offer many options, and some pie menus can pop up linear menus, and combine linear and radial items in the same menu. Pie menus just like any popup menu are shown only when requested, resulting in less visual distraction and cognitive load than toolbars and menu bars that are always shown. Pie menus show available options, in contrast to invisible mouse gestures. Pie menus, which delay appearance until the pointer is not moving, reduce intrusiveness to the same level as mouse gestures for experienced users. Pie menus take up more screen space than linear menus, and the number of slices in an individual menu must be kept low for effectiveness by using submenus. When using pie menus, submenus may overlap with the parent menu, but the parent menu may become translucent or hidden. Pie menus are most suited for actions that have been laid out by humans, and have logical grouping choices. Linear menus are most suited for dynamic, large menus that have many possible options, without any logical grouping, since pie menus can only show a limited number of menu items. Around 3-12 items can be reasonably accommodated in a radial layout, but additional items past that tend to counteract the benefits of using pie menus in the first place. This can be overcome with related techniques that allow chaining commands in one single gesture through submenus. However, using interaction techniques that are not pointer-based have proven problematic with both pie and linear menus for cluttered digital tabletop, where physical objects might occlude menu items. Pie menus are unavailable as standard graphical control element in common commercial toolkits. Video games often require custom widget development, so pie menu cost is lower in that particular scenario. Notable implementations Secret of Mana and its successor Secret of Evermore (where the menu was used to accelerate the pacing of combat) Blender, an open source
20th and 21st century The primitive conditions were intolerable for a world national capital, and the Imperial German government brought in its scientists, engineers, and urban planners to not only solve the deficiencies, but to forge Berlin as the world's model city. A British expert in 1906 concluded that Berlin represented "the most complete application of science, order and method of public life," adding "it is a marvel of civic administration, the most modern and most perfectly organized city that there is." The emergence of great factories and consumption of immense quantities of coal gave rise to unprecedented air pollution and the large volume of industrial chemical discharges added to the growing load of untreated human waste. Chicago and Cincinnati were the first two American cities to enact laws ensuring cleaner air in 1881. Pollution became a major issue in the United States in the early twentieth century, as progressive reformers took issue with air pollution caused by coal burning, water pollution caused by bad sanitation, and street pollution caused by the 3 million horses who worked in American cities in 1900, generating large quantities of urine and manure. As historian Martin Melosi notes, the generation that first saw automobiles replacing the horses saw cars as "miracles of cleanliness". By the 1940s, however, automobile-caused smog was a major issue in Los Angeles. Other cities followed around the country until early in the 20th century, when the short lived Office of Air Pollution was created under the Department of the Interior. Extreme smog events were experienced by the cities of Los Angeles and Donora, Pennsylvania in the late 1940s, serving as another public reminder. Air pollution would continue to be a problem in England, especially later during the industrial revolution, and extending into the recent past with the Great Smog of 1952. Awareness of atmospheric pollution spread widely after World War II, with fears triggered by reports of radioactive fallout from atomic warfare and testing. Then a non-nuclear event – the Great Smog of 1952 in London – killed at least 4000 people. This prompted some of the first major modern environmental legislation: the Clean Air Act of 1956. Pollution began to draw major public attention in the United States between the mid-1950s and early 1970s, when Congress passed the Noise Control Act, the Clean Air Act, the Clean Water Act, and the National Environmental Policy Act. Severe incidents of pollution helped increase consciousness. PCB dumping in the Hudson River resulted in a ban by the EPA on consumption of its fish in 1974. National news stories in the late 1970s – especially the long-term dioxin contamination at Love Canal starting in 1947 and uncontrolled dumping in Valley of the Drums – led to the Superfund legislation of 1980. The pollution of industrial land gave rise to the name brownfield, a term now common in city planning. The development of nuclear science introduced radioactive contamination, which can remain lethally radioactive for hundreds of thousands of years. Lake Karachay – named by the Worldwatch Institute as the "most polluted spot" on earth – served as a disposal site for the Soviet Union throughout the 1950s and 1960s. Chelyabinsk, Russia, is considered the "Most polluted place on the planet". Nuclear weapons continued to be tested in the Cold War, especially in the earlier stages of their development. The toll on the worst-affected populations and the growth since then in understanding about the critical threat to human health posed by radioactivity has also been a prohibitive complication associated with nuclear power. Though extreme care is practiced in that industry, the potential for disaster suggested by incidents such as those at Three Mile Island, Chernobyl, and Fukushima pose a lingering specter of public mistrust. Worldwide publicity has been intense on those disasters. Widespread support for test ban treaties has ended almost all nuclear testing in the atmosphere. International catastrophes such as the wreck of the Amoco Cadiz oil tanker off the coast of Brittany in 1978 and the Bhopal disaster in 1984 have demonstrated the universality of such events and the scale on which efforts to address them needed to engage. The borderless nature of atmosphere and oceans inevitably resulted in the implication of pollution on a planetary level with the issue of global warming. Most recently the term persistent organic pollutant (POP) has come to describe a group of chemicals such as PBDEs and PFCs among others. Though their effects remain somewhat less well understood owing to a lack of experimental data, they have been detected in various ecological habitats far removed from industrial activity such as the Arctic, demonstrating diffusion and bioaccumulation after only a relatively brief period of widespread use. A much more recently discovered problem is the Great Pacific Garbage Patch, a huge concentration of plastics, chemical sludge and other debris which has been collected into a large area of the Pacific Ocean by the North Pacific Gyre. This is a less well known pollution problem than the others described above, but nonetheless has multiple and serious consequences such as increasing wildlife mortality, the spread of invasive species and human ingestion of toxic chemicals. Organizations such as 5 Gyres have researched the pollution and, along with artists like Marina DeBris, are working toward publicizing the issue. Pollution introduced by light at night is becoming a global problem, more severe in urban centres, but nonetheless contaminating also large territories, far away from towns. Growing evidence of local and global pollution and an increasingly informed public over time have given rise to environmentalism and the environmental movement, which generally seek to limit human impact on the environment. See also Anthropocene Aspinall V. Mitchell - landmark pollution trial, 1880 Biological contamination Chemical contamination Environmental health Environmental racism Hazardous Substances Data Bank Marine pollution Overpopulation Pollutants Pollutant release and transfer register Polluter pays principle Pollution haven hypothesis Regulation of greenhouse gases under the Clean Air Act Rossby wave Plastic pollution Pollution is Colonialism Sacrifice zone Gallery References External links OEHHA proposition 65 list National Toxicology Program – from US National Institutes of Health. Reports and studies on how pollutants affect people TOXNET – NIH databases and reports on toxicology TOXMAP – Geographic Information System (GIS) that uses maps of the United States to help users visually explore data from the United States Environmental Protection Agency (EPA) Toxics Release Inventory and Superfund Basic Research Programs EPA.gov – manages Superfund sites and the pollutants in them (CERCLA). Map the EPA Superfund Toxic Release Inventory – tracks how much waste US companies release into the water and air. Gives permits for releasing specific quantities of these pollutants each year. Map EPA's Toxic Release Inventory Agency for Toxic Substances and Disease Registry – Top 20 pollutants, how they affect people, what US industries use them and the products in which they are found Toxicology Tutorials from the National Library of Medicine – resources to review human toxicology. World's Worst Polluted Places 2007, according to the Blacksmith Institute The World's Most Polluted Places at Time.com (a division of Time Magazine) Chelyabinsk: The Most Contaminated Spot on the Planet Documentary Film by Slawomir Grünberg (1996) Nieman	dioxide, chlorofluorocarbons (CFCs) and nitrogen oxides produced by industry and motor vehicles. Photochemical ozone and smog are created as nitrogen oxides and hydrocarbons react to sunlight. Particulate matter, or fine dust is characterized by their micrometre size PM10 to PM2.5. Electromagnetic pollution: the overabundance of electromagnetic radiation in their non-ionizing form, like radio waves, etc, that people are constantly exposed at, especially in large cities. It's still unknown whether or not those types of radiation have any effects on human health, though. Light pollution: includes light trespass, over-illumination and astronomical interference. Littering: the criminal throwing of inappropriate man-made objects, unremoved, onto public and private properties. Noise pollution: which encompasses roadway noise, aircraft noise, industrial noise as well as high-intensity sonar. Plastic pollution: involves the accumulation of plastic products and microplastics in the environment that adversely affects wildlife, wildlife habitat, or humans. Soil contamination occurs when chemicals are released by spill or underground leakage. Among the most significant soil contaminants are hydrocarbons, heavy metals, MTBE, herbicides, pesticides and chlorinated hydrocarbons. Radioactive contamination, resulting from 20th century activities in atomic physics, such as nuclear power generation and nuclear weapons research, manufacture and deployment. (See alpha emitters and actinides in the environment.) Thermal pollution, is a temperature change in natural water bodies caused by human influence, such as use of water as coolant in a power plant. Visual pollution, which can refer to the presence of overhead power lines, motorway billboards, scarred landforms (as from strip mining), open storage of trash, municipal solid waste or space debris. Water pollution, by the discharge of industrial wastewater from commercial and industrial waste (intentionally or through spills) into surface waters; discharges of untreated sewage, and chemical contaminants, such as chlorine, from treated sewage; release of waste and contaminants into surface runoff flowing to surface waters (including urban runoff and agricultural runoff, which may contain chemical fertilizers and pesticides; also including human feces from open defecation – still a major problem in many developing countries); groundwater pollution from waste disposal and leaching into the ground, including from pit latrines and septic tanks; eutrophication and littering. Pollutants A pollutant is a waste material that pollutes air, water, or soil. Three factors determine the severity of a pollutant: its chemical nature, the concentration, the area affected and the persistence. Sources and causes Air pollution comes from both natural and human-made (anthropogenic) sources. However, globally human-made pollutants from combustion, construction, mining, agriculture and warfare are increasingly significant in the air pollution equation. Motor vehicle emissions are one of the leading causes of air pollution. China, United States, Russia, India Mexico, and Japan are the world leaders in air pollution emissions. Principal stationary pollution sources include chemical plants, coal-fired power plants, oil refineries, petrochemical plants, nuclear waste disposal activity, incinerators, large livestock farms (dairy cows, pigs, poultry, etc.), PVC factories, metals production factories, plastics factories, and other heavy industry. Agricultural air pollution comes from contemporary practices which include clear felling and burning of natural vegetation as well as spraying of pesticides and herbicides About 400 million metric tons of hazardous wastes are generated each year. The United States alone produces about 250 million metric tons. Americans constitute less than 5% of the world's population, but produce roughly 25% of the world's , and generate approximately 30% of world's waste. In 2007, China overtook the United States as the world's biggest producer of , while still far behind based on per capita pollution (ranked 78th among the world's nations). Some of the more common soil contaminants are chlorinated hydrocarbons (CFH), heavy metals (such as chromium, cadmium – found in rechargeable batteries, and lead – found in lead paint, aviation fuel and still in some countries, gasoline), MTBE, zinc, arsenic and benzene. In 2001 a series of press reports culminating in a book called Fateful Harvest unveiled a widespread practice of recycling industrial byproducts into fertilizer, resulting in the contamination of the soil with various metals. Ordinary municipal landfills are the source of many chemical substances entering the soil environment (and often groundwater), emanating from the wide variety of refuse accepted, especially substances illegally discarded there, or from pre-1970 landfills that may have been subject to little control in the U.S. or EU. There have also been some unusual releases of polychlorinated dibenzodioxins, commonly called dioxins for simplicity, such as TCDD. Pollution can also be the consequence of a natural disaster. For example, hurricanes often involve water contamination from sewage, and petrochemical spills from ruptured boats or automobiles. Larger scale and environmental damage is not uncommon when coastal oil rigs or refineries are involved. Some sources of pollution, such as nuclear power plants or oil tankers, can produce widespread and potentially hazardous releases when accidents occur. In the case of noise pollution the dominant source class is the motor vehicle, producing about ninety percent of all unwanted noise worldwide. Greenhouse gases emissions Carbon dioxide, while vital for photosynthesis, is sometimes referred to as pollution, because raised levels of the gas in the atmosphere are affecting the Earth's climate. Disruption of the environment can also highlight the connection between areas of pollution that would normally be classified separately, such as those of water and air. Recent studies have investigated the potential for long-term rising levels of atmospheric carbon dioxide to cause slight but critical increases in the acidity of ocean waters, and the possible effects of this on marine ecosystems. In February 2007, a report by the Intergovernmental Panel on Climate Change (IPCC), representing the work of 2,500 scientists, economists, and policymakers from more than 120 countries, confirmed that humans have been the primary cause of global warming since 1950. Humans have ways to cut greenhouse gas emissions and avoid the consequences of global warming, a major climate report concluded. But to change the climate, the transition from fossil fuels like coal and oil needs to occur within decades, according to the final report this year from the UN's Intergovernmental Panel on Climate Change (IPCC). Effects Human health Adverse air quality can kill many organisms, including humans. Ozone pollution can cause respiratory disease, cardiovascular disease, throat inflammation, chest pain, and congestion. Water pollution causes approximately 14,000 deaths per day, mostly due to contamination of drinking water by untreated sewage in developing countries. An estimated 500 million Indians have no access to a proper toilet, Over ten million people in India fell ill with waterborne illnesses in 2013, and 1,535 people died, most of them children. Nearly 500 million Chinese lack access to safe drinking water. A 2010 analysis estimated that 1.2 million people died prematurely each year in China because of air pollution. The high smog levels China has been facing for a long time can do damage to civilians' bodies and cause different diseases. The WHO estimated in 2007 that air pollution causes half a million deaths per year in India. Studies have estimated that the number of people killed annually in the United States could be over 50,000. Oil spills can cause skin irritations and rashes. Noise pollution induces hearing loss, high blood pressure, stress, and sleep disturbance. Mercury has been linked to developmental deficits in children and neurologic symptoms. Older people are majorly exposed to diseases induced by air pollution. Those with heart or lung disorders are at additional risk. Children and infants are also at serious risk. Lead and other heavy metals have been shown to cause neurological problems. Chemical and radioactive substances can cause cancer and as well as birth defects. An October 2017 study by the Lancet Commission on Pollution and Health found that global pollution, specifically toxic air, water, soils and workplaces, kills nine million people annually, which is triple the number of deaths caused by AIDS, tuberculosis and malaria combined, and 15 times higher than deaths caused by wars and other forms of human violence. The study concluded that "pollution is one of the great existential challenges of the Anthropocene era. Pollution endangers the stability of the Earth’s support systems and threatens the continuing survival of human societies." Environment Pollution has been found to be present widely in the environment. There are a number of effects of this: Biomagnification describes situations where toxins (such as heavy metals) may pass through trophic levels, becoming exponentially more concentrated in the process. Carbon dioxide emissions cause ocean acidification, the ongoing decrease in the pH of the Earth's oceans as becomes dissolved. The emission of greenhouse gases leads to global warming which affects ecosystems in many ways. Invasive species can outcompete native species and reduce biodiversity. Invasive plants can contribute debris and biomolecules (allelopathy) that can alter soil and chemical compositions of an environment, often reducing native species competitiveness. Nitrogen oxides are removed from the air by rain and fertilise land which can change the species composition of ecosystems. Smog and haze can reduce the amount of sunlight received by plants to carry out photosynthesis and leads to the production of tropospheric ozone which damages plants. Soil can become infertile and unsuitable for plants. This will affect other organisms in the food web. Sulfur dioxide and nitrogen oxides can cause acid rain which lowers the pH value of soil. Organic pollution of watercourses can deplete oxygen levels and reduce species diversity. A 2022 study published in Environmental Science & Technology found that levels of anthropogenic chemical pollution have exceeded planetary boundaries and now threaten entire ecosystems around the world. Environmental health information The Toxicology and Environmental Health Information Program (TEHIP) at the United States National Library of Medicine (NLM) maintains a comprehensive toxicology and environmental health web site that includes access to resources produced by TEHIP and by other government agencies and organizations. This web site includes links to databases, bibliographies, tutorials, and other scientific and consumer-oriented resources. TEHIP also is responsible for the Toxicology Data Network (TOXNET) an integrated system of toxicology and environmental health databases that are available free of charge on the web. TOXMAP is a Geographic Information System (GIS) that is part of TOXNET. TOXMAP uses maps of the United States to help users visually explore data from the United States Environmental Protection Agency's (EPA) Toxics Release Inventory and Superfund Basic Research Programs. Crime A 2021 study found that exposure to pollution causes an increase in violent crime. School outcomes A 2019 paper linked pollution to adverse school outcomes for children. Worker productivity A number of studies show that pollution has an adverse effect on the productivity of both indoor and outdoor workers. Regulation and monitoring To protect the environment from the adverse effects of pollution, many nations worldwide have enacted legislation to regulate various types of pollution as well as to mitigate the adverse effects of pollution. Pollution control Pollution control is a term used in environmental management. It means the control of emissions and effluents into air, water or soil. Without pollution control, the waste products from overconsumption, heating, agriculture, mining, manufacturing, transportation and other human activities, whether they accumulate or disperse, will degrade the environment. In the hierarchy of controls, pollution prevention and waste minimization are more desirable than pollution control. In the field of land development, low impact development is a similar technique for the prevention of urban runoff. Practices Recycling Reusing Waste minimisation Mitigating Pollution prevention Compost Pollution control devices Air pollution control Thermal oxidizer Dust collection systems Baghouses Cyclones Electrostatic precipitators Scrubbers Baffle spray scrubber Cyclonic spray scrubber Ejector venturi scrubber Mechanically aided scrubber Spray tower
extended reach and thrusting tactics used in pike square or phalanx combat; those designed to increase leverage (thanks to hands moving freely on a pole) to maximize centrifugal force against cavalry; and those designed for throwing tactics used in skirmish line combat. Because their versatility, high effectiveness and cheap cost, polearms experimentation led to many variants and were the most frequently used weapons on the battlefield: bills, picks, dane axes, spears, glaives, guandaos, pudaos, poleaxes, halberds, harpoons, sovnyas, tridents, naginatas, bardiches, war scythes, and lances are all varieties of pole arms. Pole arms were common weapons on post-classical battlefields of Asia and Europe. Their range and impact force made them effective weapons against armored warriors on horseback, because they could be dismounted and/or penetrate said armor. The Renaissance saw a plethora of varieties. Pole arms in modern times are largely constrained to ceremonial military units such as the Papal Swiss Guard or Yeomen of the Guard, or traditional martial arts. Chinese martial arts in particular have preserved a wide variety of weapons and techniques. Classification difficulties The classification of pole weapons can be difficult, and European weapon classifications in particular can be confusing. This can be due to a number of factors, including uncertainty in original descriptions, changes in weapons or nomenclature through time, mistranslation of terms, and the well-meaning inventiveness of later experts. For example, the word "halberd" is also used to translate the Chinese ji and also a range of medieval Scandinavian weapons as described in sagas, such as the atgeir. As well, all pole arms developed from three early tools (the axe, the scythe, and the knife) and one weapon, the spear. In the words of the arms expert Ewart Oakeshott, While men-at-arms may have been armed with custom designed military weapons, militias were often armed with whatever was available. These may or may not have been mounted on poles and described by one of more names. The problems with precise definitions can be inferred by a contemporary description of Royalist infantry which were engaged in the Battle of Birmingham (1643) during the first year of English Civil War (in the early modern period). The infantry regiment that accompanied Prince Rupert's cavalry were armed: List of pole weapons Ancient pole weapons European Falx Rhomphaia Kontos (weapon) Dory (spear) Sarissa Xyston Asian Dagger-axe The dagger-axe, or gee (Chinese: 戈; pinyin: gē; Wade–Giles: ko; sometimes confusingly translated "halberd") is a type of weapon that was in use from Shang dynasty until at least Han dynasty China. It consists of a dagger-shaped blade made of bronze (or later iron) mounted by the tang to a perpendicular wooden shaft: a common Bronze Age infantry weapon, also used by charioteers. Some dagger axes include a spear-point. There is a (rare) variant type with a divided two-part head, consisting of the usual straight blade and a scythe-like blade. Other rarities include archaeology findings with two or sometimes three blades stacked in line on top of a pole, but were generally thought as ceremonial pole arms. Though the weapon saw frequent use in ancient China, the use of the dagger-axe decreased dramatically after the Qin and Han dynasties. The ji combines the dagger axe with a spear. By the post-classical Chinese dynasties, with the decline of chariot warfare, the use of the dagger-axe was almost nonexistent. Ji The ji (Chinese: 戟) was created by combining the dagger-axe with a spear. It was used as a military weapon at least as early as the Shang dynasty until the end of the Northern and Southern dynasties. Ngao The ngao or ngau (ง้าว,ของ้าว) is a Thai pole arm that was traditionally used by elephant-riding infantry and is still used by practitioners of krabi krabong. Known in Malay as a dap, it consists of a wooden shaft with a curved blade fashioned onto the end, and is similar in design to the Korean woldo. Usually, it also had a hook (ขอ) between the blade and shaft used for commanding the elephant. The elephant warrior used the ngao like a blade from atop an elephant or horse during battle. Post-classical pole weapons European Danish axe The Dane axe is a weapon with a heavy crescent-shaped head mounted on a haft in length. Originally a Viking weapon, it was adopted by the Anglo-Saxons and Normans in the 11th century, spreading through Europe in the 12th and 13th centuries. Variants of this basic weapon continued in use in Scotland and Ireland into the 16th century. A form of 'long axe'. Sparth axe In the 13th century, variants on the Danish axe are seen. Described in English as a sparth (from the Old Norse ) or pale-axe, the weapon featured a larger head with broader blade, the rearward part of the crescent sweeping up to contact (or even be attached to) the haft. In Ireland, this axe was known as a sparr axe. Originating in either Western Scotland or Ireland, the sparr was widely used by the galloglass. Although sometimes said to derive from the Irish for a joist or beam, a more likely definition is as a variant of sparth. Although attempts have been made to suggest that the sparr had a distinctive shaped head, illustrations and surviving weapons show there was considerable variation and the distinctive feature of the weapon was its long haft. Fauchard A fauchard is a type of pole arm which was used in medieval Europe from the 11th through the 14th centuries. The design consisted of a curved blade put atop a pole. The blade bore a moderate to strong curve along its length; however, unlike a bill or guisarme, the cutting edge was on the convex side. Guisarme A guisarme (sometimes gisarme, giserne or bisarme) was a pole weapon used in Europe primarily between 1000 and 1400. It was used primarily to dismount knights and horsemen. Like most pole arms it was developed by peasants by combining hand tools with long poles, in this case by putting a pruning hook onto a spear shaft. While hooks are fine for dismounting horsemen from mounts, they lack the stopping power of a spear especially when dealing with static opponents. While early designs were simply a hook on the end of a long pole, later designs implemented a small reverse spike on the back of the blade. Eventually weapon makers incorporated the usefulness of the hook in a variety of different pole arms and guisarme became a catch-all for any weapon that included a hook on the blade. Ewart Oakeshott has proposed an alternative description of the weapon as a	weapons on the battlefield: bills, picks, dane axes, spears, glaives, guandaos, pudaos, poleaxes, halberds, harpoons, sovnyas, tridents, naginatas, bardiches, war scythes, and lances are all varieties of pole arms. Pole arms were common weapons on post-classical battlefields of Asia and Europe. Their range and impact force made them effective weapons against armored warriors on horseback, because they could be dismounted and/or penetrate said armor. The Renaissance saw a plethora of varieties. Pole arms in modern times are largely constrained to ceremonial military units such as the Papal Swiss Guard or Yeomen of the Guard, or traditional martial arts. Chinese martial arts in particular have preserved a wide variety of weapons and techniques. Classification difficulties The classification of pole weapons can be difficult, and European weapon classifications in particular can be confusing. This can be due to a number of factors, including uncertainty in original descriptions, changes in weapons or nomenclature through time, mistranslation of terms, and the well-meaning inventiveness of later experts. For example, the word "halberd" is also used to translate the Chinese ji and also a range of medieval Scandinavian weapons as described in sagas, such as the atgeir. As well, all pole arms developed from three early tools (the axe, the scythe, and the knife) and one weapon, the spear. In the words of the arms expert Ewart Oakeshott, While men-at-arms may have been armed with custom designed military weapons, militias were often armed with whatever was available. These may or may not have been mounted on poles and described by one of more names. The problems with precise definitions can be inferred by a contemporary description of Royalist infantry which were engaged in the Battle of Birmingham (1643) during the first year of English Civil War (in the early modern period). The infantry regiment that accompanied Prince Rupert's cavalry were armed: List of pole weapons Ancient pole weapons European Falx Rhomphaia Kontos (weapon) Dory (spear) Sarissa Xyston Asian Dagger-axe The dagger-axe, or gee (Chinese: 戈; pinyin: gē; Wade–Giles: ko; sometimes confusingly translated "halberd") is a type of weapon that was in use from Shang dynasty until at least Han dynasty China. It consists of a dagger-shaped blade made of bronze (or later iron) mounted by the tang to a perpendicular wooden shaft: a common Bronze Age infantry weapon, also used by charioteers. Some dagger axes include a spear-point. There is a (rare) variant type with a divided two-part head, consisting of the usual straight blade and a scythe-like blade. Other rarities include archaeology findings with two or sometimes three blades stacked in line on top of a pole, but were generally thought as ceremonial pole arms. Though the weapon saw frequent use in ancient China, the use of the dagger-axe decreased dramatically after the Qin and Han dynasties. The ji combines the dagger axe with a spear. By the post-classical Chinese dynasties, with the decline of chariot warfare, the use of the dagger-axe was almost nonexistent. Ji The ji (Chinese: 戟) was created by combining the dagger-axe with a spear. It was used as a military weapon at least as early as the Shang dynasty until the end of the Northern and Southern dynasties. Ngao The ngao or ngau (ง้าว,ของ้าว) is a Thai pole arm that was traditionally used by elephant-riding infantry and is still used by practitioners of krabi krabong. Known in Malay as a dap, it consists of a wooden shaft with a curved blade fashioned onto the end, and is similar in design to the Korean woldo. Usually, it also had a hook (ขอ) between the blade and shaft used for commanding the elephant. The elephant warrior used the ngao like a blade from atop an elephant or horse during battle. Post-classical pole weapons European Danish axe The Dane axe is a weapon with a heavy crescent-shaped head mounted on a haft in length. Originally a Viking weapon, it was adopted by the Anglo-Saxons and Normans in the 11th century, spreading through Europe in the 12th and 13th centuries. Variants of this basic weapon continued in use in Scotland and Ireland into the 16th century. A form of 'long axe'. Sparth axe In the 13th century, variants on the Danish axe are seen. Described in English as a sparth (from the Old Norse ) or pale-axe, the weapon featured a larger head with broader blade, the rearward part of the crescent sweeping up to contact (or even be attached to) the haft. In Ireland, this axe was known as a sparr axe. Originating in either Western Scotland or Ireland, the sparr was widely used by the galloglass. Although sometimes said to derive from the Irish for a joist or beam, a more likely definition is as a variant of sparth. Although attempts have been made to suggest that the sparr had a distinctive shaped head, illustrations and surviving weapons show there was considerable variation and the distinctive feature of the weapon was its long haft. Fauchard A fauchard is a type of pole arm which was used in medieval Europe from the 11th through the 14th centuries. The design consisted of a curved blade put atop a pole. The blade bore a moderate to strong curve along its length; however, unlike a bill or guisarme, the cutting edge was on the convex side. Guisarme A guisarme (sometimes gisarme, giserne or bisarme) was a pole weapon used in Europe primarily between 1000 and 1400. It was used primarily to dismount knights and horsemen. Like most pole arms it was developed by peasants by combining hand tools with long poles, in this case by putting a pruning hook onto a spear shaft. While hooks are fine for dismounting horsemen from mounts, they lack the stopping power of a spear especially when dealing with static opponents. While early designs were simply a hook on the end of a long pole, later designs implemented a small reverse spike on the back of the blade. Eventually weapon makers incorporated the usefulness of the hook in a variety of different pole arms and guisarme became a catch-all for any weapon that included a hook on the blade. Ewart Oakeshott has proposed an alternative description of the weapon as a crescent shaped socketed axe. Glaive A glaive is a pole arm consisting of a single-edged tapering blade similar in shape to a modern kitchen knife on the end of a pole. The blade was around long, on the end of a pole long. However, instead of having a tang like a sword or naginata, the blade is affixed in a socket-shaft configuration similar to an axe head, both the blade and shaft varying in length. Illustrations in the 13th century Maciejowski Bible show a short staffed weapon with a long blade used by both infantry and cavalry. Occasionally glaive blades were created with a small hook or spike on the reverse side. Such glaives
PHD or PhD may refer to: Doctor of Philosophy (PhD), an academic qualification Entertainment PhD: Phantasy Degree, a Korean comic series Piled	series Piled Higher and Deeper, a web comic Ph.D. (band), a 1980s British group Ph.D. (Ph.D. album) Ph.D. (Art Farmer album) "PHD", a song on the album Tweekend by the Crystal Method PHD Flopper, a popular perk drink
Violations by a rogue state could be checked via collateral attack: when a plaintiff sought recovery against a defendant's assets in another state, that state could refuse judgment on the grounds that the original judgment was invalid. Difficulties in applying Pennoyer territorial jurisdiction Following Pennoyer, extreme applications of territorial jurisdiction revealed imperfections in the doctrine, and societal changes began to present new problems as the United States' national economy became more integrated by increasingly efficient multi-state transportation technology and business practices. While determining the physical location of an individual for the purposes of in personam jurisdiction was easy enough, applying the same principle to non-physical entities became difficult. Courts were presented with the question of where a company was present and amenable to service for the purpose of in personam jurisdiction over the company. Extension of quasi in rem jurisdiction led to extreme results that threatened the justification for the jurisdiction. Bearing in mind that territorial jurisdiction existed in a pre-industrial society where transportation across the country was difficult, long, and potentially treacherous, and consider the hypothetical wherein Alice owes Bob money, and Bob owes Carmel, a resident of New York, money. Carmel seeks to recover on Bob's debt to Carmel, however cannot do so because Bob avoids Carmel by travelling to California. Alice, however, happens to travel through New York. Carmel serves notice upon Alice, and attaches Alice's debt to Bob (considered to be property within the state) to the proceeding. Alice can no more certainly provide notice to Bob in California than Carmel could provide, and the transient and involuntary exposure of Bob to being hauled into court in New York by this attachment seems to erode the original rationale of quasi in rem jurisdiction. The US Supreme Court largely abolished the exercise of jurisdiction on the basis of quasi in rem in Shaffer v. Heitner, except in exceptional circumstances, which sometimes would arise while dealing with real property such as land, and when the owner of the land cannot be found. Modern Constitutional doctrine: International Shoe doctrine In the modern era, the reach of personal jurisdiction has been expanded by judicial re-interpretation and legislative enactments. Under the new and current doctrine, a state court may only exert personal jurisdiction over an individual or entity with "sufficient minimal contacts" with the forum state such that the particular suit "does not offend 'traditional notions of fair play and justice.'" The "minimum contacts" must be purposefully directed towards the state by the defendant. This jurisdiction was initially limited to the particulars of the International Shoe Co. v. Washington holding, that is to jurisdictional inquiries regarding companies, but was soon extended to apply to all questions of personal jurisdiction. When an individual or entity has no "minimum contacts" with a forum State, the Due Process Clause of the Fourteenth Amendment prohibits that State from acting against that individual, or entity. The lack of "minimum contacts" with the owner of property also constitutionally prohibits action against that property (in rem jurisdiction) even when the property is located within the forum state. What constitutes sufficient "minimum contacts" has been delineated in numerous cases which followed the International Shoe decision. For example, in Hanson v. Denckla, the Court proclaimed the "unilateral activity of those who claim some relationship with a nonresident cannot satisfy the requirement of contact with the forum State. The application of that rule will vary with the nature and quality of the defendant's activity, but it is essential in each case that there be some act by which the defendant purposefully avails itself of the privilege of conducting activities within the forum State, thus invoking the benefits and protection of its laws." The additional requirement of "'purposeful availment' ensures that a defendant will not be hauled into a jurisdiction solely as a result of 'random,' 'fortuitous,' or 'attenuated' contacts, or of the unilateral activity of another party or a third person". Jurisdiction may, however, be exercised, under some circumstances, even though the defendant never physically entered the forum state. In addition, the claim must arise from those contacts that the defendant had with the forum state. In addition to the minimum contacts test asserted in International Shoe, the assertion of specific personal jurisdiction must be reasonable. The Court in World-Wide Volkswagen Corp. v. Woodson asserted a five-part test for determining if the assertion of personal jurisdiction in a forum state was reasonable. This test considers: the burden on the defendant from litigating in the forum state; the interest of the forum state in having the case adjudicated there; the interests of the plaintiff in adjudicating in the forum state; the interests of the inter-state judiciary—that is, that a court's assertion of personal jurisdiction over an out-of state defendant would not overreach and preempt the interests and judicial sovereignty of another state; and the interests in preserving the judicial integrity of the several states—that is, ensuring one court's assertion of personal jurisdiction over an out of state defendant does not violate the Due Process Clause of the Fourteenth Amendment. In another recent case of Goodyear Dunlop Tires Operations, S. A. v. Brown, Justice Ginsburg held that for the exercise of general jurisdiction in personam, the defendant must be "essentially at home." This applies when the defendant has contacts with the forum state, but the claim that arises is not related to those contacts. For example, if Harrods (a British store) sets up an office in California to export and sell goods there, and because of that someone gets injured, it would be amenable to suit in California for that injury. On the other hand, if someone is injured in Harrods in London and for some reason finds that California law is more favorable and decides to sue in California, the suit would not be maintainable under general jurisdiction since the contacts that Harrods has are not continuous and systematic, and they are not "essentially at home" in California. However, there would be personal jurisdiction. By selling shoes in California, Harrod’s purposefully availed itself of the benefits of California law and the lawsuit arose out of that contact. This holding was reaffirmed in 2014 by the Supreme Court in Daimler AG v. Bauman. Statutory authorization While the Pennoyer and later Shoe doctrines limit the maximum power of a sovereign state, courts must also have authorization to exercise the state's power; an individual state may choose to not grant its courts the full power that the state is Constitutionally permitted to exercise. Similarly, the jurisdiction of Federal courts (other than the Supreme Court) are statutorily-defined. Thus, a particular exercise of personal jurisdiction must not only be permitted by Constitutional doctrine, but be statutorily authorized as well. Under Pennoyer, personal jurisdiction was authorized by statutes authorizing service of process, but these methods of service often lacked because they required such service to be effected by officers of the state, such as sheriffs – an untenable method for defendants located outside of the state but still subject to jurisdiction due to their contacts with the state. Subsequent to the development of the Shoe Doctrine, states have enacted so-called long-arm statutes, by which courts in a state can serve process and thus exercise jurisdiction over a party located outside the state. The doctrine of International Shoe applies only in cases where there is no presence in the forum state. For example, if A committed a tort in State X. He is sued by B and B serves him with process just before he leaves State X before the flight was took off, the service would be valid and State X would have jurisdiction over A. If A did not comply with the final judgement passed by the courts of State X, B could enforce that judgement in the state where A resides under the full faith and credit clause of the US Constitution. There was one case where a defendant was served while the airplane was in the air over the forum State, and the federal district court held that this was valid service, since at law the territory of a state includes the airspace above the State. Relationship to venue Venue and personal jurisdiction are closely related for practical purposes. A lawyer should usually perform joint analysis of personal jurisdiction and venue issues. Personal jurisdiction is largely a constitutional requirement, though also shaped by state long-arm statutes and Rule 4 of the Federal Rules of Civil Procedure, while venue is purely statutory. It is possible for either venue or personal jurisdiction to preclude a court from hearing a case. Consider these examples: Personal jurisdiction is the limiting factor. In World-Wide Volkswagen Corp. v. Woodson, the plaintiffs sued, in an Oklahoma state court, an automobile dealership based in New York for damages from an explosion that occurred on June 11, 1977, as the plaintiffs drove the car through Oklahoma. Had the plaintiffs sued in U.S. federal court sited in Oklahoma, personal jurisdiction against the dealership would have been unavailable, as the dealership did not have minimum contacts with the forum state. Venue, however, would have been proper under , the general federal venue statute, because Oklahoma was a state in which a substantial part of the events or omissions giving rise to the claim occurred. However, the United States Supreme Court found that the defendants (World-Wide Volkswagen Corp.) did not have the minimum contacts with Oklahoma necessary to create personal jurisdiction there. [World-Wide Volkswagen was one of the "defendants"; the case cited is WWV Corp (original defendant) v. Woodson (the Oklahoma state judge) ] Venue is the limiting factor. Suppose Dale resides in California. Peter from Nevada wants to sue Dale for battery which Dale committed against Peter in California. Peter knows Dale is going to a week-long conference in South Carolina. Peter realizes that Dale would settle a suit that would take place in South	rule of law – for example an absolute monarchy with no independent judiciary – may arbitrarily choose to assert jurisdiction over a case without citing any particular justification. Such assertion can cause problems, such as encouraging other countries to take arbitrary actions over foreign citizens and property, or even provoking skirmishes or armed conflict. In practice, many countries operate by one or another principles, either in written law or in practice, which communicate when the country will and will not assert jurisdiction: treaty jurisdiction — An international treaty explicitly decides the issue. territorial principle — A country asserts jurisdiction over people, property, and events taking place on its own territory. nationality principle — A country asserts jurisdiction over the conduct of its citizens, anywhere in the world. passive personality principle — A country asserts jurisdiction over acts committed against its citizens, anywhere in the world. protective principle — A country asserts jurisdiction over issues that affect its interests, such as conspiracies to overthrow its government, or resources critical to its economy (such as access to an international waterway) universal jurisdiction — A country asserts jurisdiction over certain acts committed by anyone, anywhere in the world. Usually reserved for exceptionally serious crimes, such as war crimes and crimes against humanity. Different principles are applied by different countries, and different principles may be applied by the same country in different circumstances. Determination of whether or not a court has jurisdiction to hear a case is the first stage of a conflict of laws proceeding, potentially followed by choice of law to determine which jurisdiction's laws apply. Executive prosecutorial authority and foreign policy also play a role in scope and practical impact of jurisdiction choices. Any assertion of jurisdiction based on anything other than the territorial principle is known as extraterritorial jurisdiction. Prosecution of a case against an out-of-territory defendant is known as assertion of long-arm jurisdiction. When a person commits a crime in a foreign country against the laws of that country, usually the host country is responsible for prosecution. The Vienna Convention on Consular Relations requires that the host country notify the foreign embassy, potentially allowing the foreign country to assist in legal defense and monitor conditions of detention. (Most countries protect their citizens against foreign powers in general.) Foreign diplomats enjoy diplomatic immunity in many countries based on the Vienna Convention on Diplomatic Relations or bilateral agreement, and foreign military personnel may be subject to the jurisdiction of their home country based on a status of forces agreement or Visiting Forces Agreement. If a person is not physically present in the country which wishes to prosecute a case, that country may either wait until the person enters the national territory, or pursue extradition by legal or extralegal means, and with or without a general extradition treaty. Some countries (like China) prefer to prosecute their own citizens for crimes committed abroad rather than extradite them. Other countries defer to the host country. When a crime is committed outside the territory of any country, such as in Antarctica, on watercraft in international waters, on aircraft in international airspace, and on spacecraft, jurisdiction is usually determined by the nationality of defendants or victims, or by the flag state of the vessel. This is determined by the admiralty law of the countries involved and in international agreements. History in English and U.S. law The concept of personal jurisdiction in English law has its origin in the idea that a monarch could not exercise power over persons or property located outside of his or her kingdom. To some degree, this was a de facto rule; the monarch's men could not arrest people or seize property outside the kingdom without risking physical conflict with the soldiers and police of other kingdoms. Slowly this principle was incorporated into written law, but problems arose in cases where property owners could not be sued because they had left the kingdom or had died and therefore were not present within the kingdom at the time they were being sued. To solve this problem, the courts created another type of jurisdiction, called quasi in rem, that is, jurisdiction over the land itself, even if the person who owned the land was not in the country. However, this jurisdiction was limited to the settlement of debts owed by the owner of the land. In the United States, the exercise of personal jurisdiction by a court must both comply with Constitutional limitations, and be authorized by a statute. In the United Kingdom, the exercise of personal jurisdiction does not need a statutory basis, since the United Kingdom does not have a written constitution. United States The intersection of American federalism and the rules and theories of jurisdiction inherited from the common law of England has resulted in a highly complex body of law respecting personal jurisdiction in the United States. These rules limit both state and federal courts in their ability to hear cases. Principles of personal jurisdiction Three fundamentals of personal jurisdiction constrain the ability of courts in the United States to bind individuals or property to its decisions: consent, power, and notice. Consent The United States legal system is an adversarial system. Civil suits cannot be initiated by third parties, but must be filed by the aggrieved party who seeks redress. Generally, the action is initiated in the jurisdiction where the event occurred, where the defendant can be served or where the parties have agreed to have the case located. The filing of a complaint or prayer for relief is a voluntary action by the person aggrieved, and as a necessity of this request, the person seeking relief consents to be bound by the judgment of the court. The doctrine of consent is also extended to defendants who attend and litigate actions without challenging the court's personal jurisdiction. Consent may also derive from a pre-litigation agreement by the parties, such as a forum selection clause in a contract (not to be confused with a choice of law clause). Doctrines such as claim preclusion prevent re-litigation of failed complaints in alternative forums. Claim preclusion does not, however, prevent the refiling of a claim that was filed in a court that did not have personal jurisdiction over the defendant. Power In cases where a defendant challenges personal jurisdiction, a court may still exercise personal jurisdiction if it has independent power to do so. This power is founded in the inherent nature of the State: sovereignty over secular affairs within its territory. Notice The Fifth and Fourteenth Amendment to the United States Constitution preserve the right of the individual to due process. Due process requires that notice be given in a manner "reasonably calculated" to inform a party of the action affecting him. Originally, "Notice" (and the power of the State) was often exercised more forcefully, the defendant in a civil case sometimes being seized and brought before the court under a writ of capias ad respondendum. Notice in such a case is inferred from consent of the defendant to go with the officer. Nowadays, when exercising power over an individual without consent, notice is usually given by formal delivery of suitable papers to the defendant (service of process). Historical background: territorial jurisdiction Originally, jurisdiction over parties in the United States was determined by strict interpretation of the geographic boundaries of each state's sovereign power. In Pennoyer v. Neff, the Supreme Court discussed that though each state ceded certain powers (e.g. foreign relations) to the Federal Government or to no entity at all (e.g. the powers that are eliminated by the protections of the bill of rights), the states retained all the other powers of sovereignty, including the exclusive power to regulate the affairs of individuals and property within its territory. Necessarily following from this, one state's exercise of power could not infringe upon the sovereignty of another state. Thus, Constitutional limitations applied to the validity of state court judgments. Three types of jurisdiction developed, collectively termed territorial jurisdiction because of their reliance upon territorial control: in personam jurisdiction, in rem jurisdiction, and quasi in rem jurisdiction. Some sources refer to all three types of territorial jurisdiction as personal jurisdiction, since most actions against property (in rem jurisdiction) bear, in the end, upon the rights and obligations of persons. Others continue to recognize the traditional distinction between personal jurisdiction and jurisdiction over property, even after Shaffer v. Heitner (discussed below). In personam jurisdiction referred to jurisdiction over a particular person (or entity, such as a company). In personam jurisdiction, if held by a state court, permitted that court to rule upon any case over which it otherwise held jurisdiction. Under territorial jurisdiction, pure in personam jurisdiction could only be established by serving notice upon the individual while that individual was within the territory of the state. In rem jurisdiction referred to jurisdiction over a particular piece of property, most commonly real estate or land. Certain cases, notably government suits for unpaid property taxes, proceed not against an individual but against their property directly. Under territorial jurisdiction, in rem jurisdiction could be exercised by the courts of a state by seizing the property in question. Since an actual tract of land could not literally be brought into a courtroom as a person could, this was effected by giving notice upon the real property itself. In rem jurisdiction was thus supported by the assumption that the owner of that property, having a concrete economic interest in the property, had a duty to look after the affairs of their property, and would be notified of the pending case by such seizure. In rem jurisdiction was limited to deciding issues regarding the specific property in question. Quasi in rem jurisdiction involved the seizure of property held by the individual against whom the suit was brought, and attachment of that property to the case in question. This form of territorial jurisdiction developed from the rationale of in rem jurisdiction, namely that seizure of the property was reasonably calculated to inform an individual of the proceedings against them. Once a valid judgment was obtained against an individual, however, the plaintiff could pursue recovery against the assets of the defendant regardless of their location, as other states were obligated by the Full Faith and Credit Clause of the Constitution to recognize such a judgment (i.e. had ceded their power to refuse comity to fellow states of the Union). Violations by a rogue state could be checked via collateral attack: when a plaintiff sought recovery against a defendant's assets in another state, that state could refuse judgment on the grounds that the original judgment was invalid. Difficulties in applying Pennoyer territorial jurisdiction Following Pennoyer, extreme applications of territorial jurisdiction revealed imperfections in the doctrine, and societal changes began to present new problems as the United States' national economy became more integrated by increasingly efficient multi-state transportation technology and business practices. While determining the physical location of an individual for the purposes of in personam jurisdiction was easy enough, applying the same principle to non-physical entities became difficult. Courts were presented with the question of where a company was present and amenable to service for the purpose of in personam jurisdiction over the company. Extension
the cases N = 151 or 313. Both Wallis and William Brouncker gave solutions to these problems, though Wallis suggests in a letter that the solution was due to Brouncker. John Pell's connection with the equation is that he revised Thomas Branker's translation of Johann Rahn's 1659 book Teutsche Algebra into English, with a discussion of Brouncker's solution of the equation. Leonhard Euler mistakenly thought that this solution was due to Pell, as a result of which he named the equation after Pell. The general theory of Pell's equation, based on continued fractions and algebraic manipulations with numbers of the form was developed by Lagrange in 1766–1769. Solutions Fundamental solution via continued fractions Let denote the sequence of convergents to the regular continued fraction for . This sequence is unique. Then the pair solving Pell's equation and minimizing x satisfies x1 = hi and y1 = ki for some i. This pair is called the fundamental solution. Thus, the fundamental solution may be found by performing the continued fraction expansion and testing each successive convergent until a solution to Pell's equation is found. The time for finding the fundamental solution using the continued fraction method, with the aid of the Schönhage–Strassen algorithm for fast integer multiplication, is within a logarithmic factor of the solution size, the number of digits in the pair . However, this is not a polynomial-time algorithm because the number of digits in the solution may be as large as , far larger than a polynomial in the number of digits in the input value n. Additional solutions from the fundamental solution Once the fundamental solution is found, all remaining solutions may be calculated algebraically from expanding the right side, equating coefficients of on both sides, and equating the other terms on both sides. This yields the recurrence relations Concise representation and faster algorithms Although writing out the fundamental solution (x1, y1) as a pair of binary numbers may require a large number of bits, it may in many cases be represented more compactly in the form using much smaller integers ai, bi, and ci. For instance, Archimedes' cattle problem is equivalent to the Pell equation , the fundamental solution of which has digits if written out explicitly. However, the solution is also equal to where and and only have 45 and 41 decimal digits respectively. Methods related to the quadratic sieve approach for integer factorization may be used to collect relations between prime numbers in the number field generated by and to combine these relations to find a product representation of this type. The resulting algorithm for solving Pell's equation is more efficient than the continued fraction method, though it still takes more than polynomial time. Under the assumption of the generalized Riemann hypothesis, it can be shown to take time where N = log n is the input size, similarly to the quadratic sieve. Quantum algorithms Hallgren showed that a quantum computer can find a product representation, as described above, for the solution to Pell's equation in polynomial time. Hallgren's algorithm, which can be interpreted as an algorithm for finding the group of units of a real quadratic number field, was extended to more general fields by Schmidt and Völlmer. Example As an example, consider the instance of Pell's equation for n = 7; that is, The sequence of convergents for the square root of seven are {\| class="wikitable" style="text-align:center;" \|- ! h/k (convergent) ! h2 − 7k2 (Pell-type approximation) \|- \| 2/1 \| −3 \|- \| 3/1 \| +2 \|- \| 5/2 \| −3 \|- \| 8/3 \| +1 \|} Therefore, the fundamental solution is formed by the pair (8, 3). Applying the recurrence formula to this solution generates the infinite sequence of solutions (1, 0); (8, 3); (127, 48); (2024, 765); (32257, 12192); (514088, 194307); (8193151, 3096720); (130576328, 49353213); ... (sequence (x) and (y) in OEIS) The smallest solution can be very large. For example, the smallest solution to is (, ), and this is the equation which Frenicle challenged Wallis to solve. Values of n such that the smallest solution of is greater than the smallest solution for any smaller value of n are 1, 2, 5, 10, 13, 29, 46, 53, 61, 109, 181, 277, 397, 409, 421, 541, 661, 1021, 1069, 1381, 1549, 1621, 2389, 3061, 3469, 4621, 4789, 4909, 5581, 6301, 6829, 8269, 8941, 9949, ... . (For these records, see for x and for y.) List of fundamental solutions of Pell's equations The following is a list of the fundamental solution to with n ≤ 128. For square n, there is no solution except (1, 0). The values of x are sequence and those of y are sequence in OEIS. Connections Pell's equation has connections to several other important subjects in mathematics. Algebraic number theory Pell's equation is closely related to the theory of algebraic numbers, as the formula is the norm for the ring and for the closely related quadratic field . Thus, a pair of integers solves Pell's equation if and only if is a unit with norm 1 in . Dirichlet's unit theorem, that all units of can be expressed as powers of a single fundamental unit (and multiplication by a sign), is an algebraic restatement of the fact that all solutions to the Pell's equation can be generated from the fundamental solution. The fundamental unit can in general be found by solving a Pell-like equation but it does not always correspond directly to the fundamental solution of Pell's equation itself, because the fundamental unit may have norm −1 rather than 1 and its coefficients may be half integers rather than integers. Chebyshev polynomials Demeyer mentions a connection between Pell's equation and the Chebyshev polynomials: If and are the Chebyshev polynomials of the first and second kind respectively, then these polynomials satisfy a form of Pell's equation in any polynomial ring , with : Thus, these polynomials can be generated by the standard technique for Pell's equations of taking powers of a fundamental solution: It may further be observed that if are the solutions to any integer Pell's equation, then and . Continued fractions A general development of solutions of Pell's equation in terms of continued fractions of can be presented, as the solutions x and y are approximates to the square root of n and thus are a special case of continued fraction approximations for quadratic irrationals. The relationship to the continued fractions implies that the solutions to Pell's equation form a semigroup subset of the modular group. Thus, for example, if p and q satisfy Pell's equation, then is a matrix of unit determinant. Products of such matrices take exactly the same form, and thus all such products yield solutions to Pell's equation. This can be understood in part to arise from the fact that successive convergents of a continued fraction share the same property: If pk−1/qk−1 and pk/qk are two successive convergents of a continued fraction, then the matrix has determinant (−1)k. Smooth numbers Størmer's theorem applies Pell equations to find pairs of consecutive smooth numbers, positive integers whose prime factors are all smaller than a given value. As part of this theory, Størmer also investigated divisibility relations among solutions to Pell's equation; in particular, he showed that each solution other than the fundamental solution has a prime factor that does not divide n. The negative Pell's equation The negative Pell's equation is given by and has also been extensively studied. It can be solved by the same method of continued fractions and has solutions if and only if the period of the continued fraction has odd length. However, it	1 and y = 0. Joseph Louis Lagrange proved that, as long as n is not a perfect square, Pell's equation has infinitely many distinct integer solutions. These solutions may be used to accurately approximate the square root of n by rational numbers of the form x/y. This equation was first studied extensively in India starting with Brahmagupta, who found an integer solution to in his Brāhmasphuṭasiddhānta circa 628. Bhaskara II in the 12th century and Narayana Pandit in the 14th century both found general solutions to Pell's equation and other quadratic indeterminate equations. Bhaskara II is generally credited with developing the chakravala method, building on the work of Jayadeva and Brahmagupta. Solutions to specific examples of Pell's equation, such as the Pell numbers arising from the equation with n = 2, had been known for much longer, since the time of Pythagoras in Greece and a similar date in India. William Brouncker was the first European to solve Pell's equation. The name of Pell's equation arose from Leonhard Euler mistakenly attributing Brouncker's solution of the equation to John Pell. History As early as 400 BC in India and Greece, mathematicians studied the numbers arising from the n = 2 case of Pell's equation, and from the closely related equation because of the connection of these equations to the square root of 2. Indeed, if x and y are positive integers satisfying this equation, then x/y is an approximation of . The numbers x and y appearing in these approximations, called side and diameter numbers, were known to the Pythagoreans, and Proclus observed that in the opposite direction these numbers obeyed one of these two equations. Similarly, Baudhayana discovered that x = 17, y = 12 and x = 577, y = 408 are two solutions to the Pell equation, and that 17/12 and 577/408 are very close approximations to the square root of 2. Later, Archimedes approximated the square root of 3 by the rational number 1351/780. Although he did not explain his methods, this approximation may be obtained in the same way, as a solution to Pell's equation. Likewise, Archimedes's cattle problem — an ancient word problem about finding the number of cattle belonging to the sun god Helios — can be solved by reformulating it as a Pell's equation. The manuscript containing the problem states that it was devised by Archimedes and recorded in a letter to Eratosthenes, and the attribution to Archimedes is generally accepted today. Around AD 250, Diophantus considered the equation where a and c are fixed numbers, and x and y are the variables to be solved for. This equation is different in form from Pell's equation but equivalent to it. Diophantus solved the equation for (a, c) equal to (1, 1), (1, −1), (1, 12), and (3, 9). Al-Karaji, a 10th-century Persian mathematician, worked on similar problems to Diophantus. In Indian mathematics, Brahmagupta discovered that a form of what is now known as Brahmagupta's identity. Using this, he was able to "compose" triples and that were solutions of , to generate the new triples and Not only did this give a way to generate infinitely many solutions to starting with one solution, but also, by dividing such a composition by , integer or "nearly integer" solutions could often be obtained. For instance, for , Brahmagupta composed the triple (10, 1, 8) (since ) with itself to get the new triple (192, 20, 64). Dividing throughout by 64 ("8" for and ) gave the triple (24, 5/2, 1), which when composed with itself gave the desired integer solution (1151, 120, 1). Brahmagupta solved many Pell's equations with this method, proving that it gives solutions starting from an integer solution of for k = ±1, ±2, or ±4. The first general method for solving the Pell's equation (for all N) was given by Bhāskara II in 1150, extending the methods of Brahmagupta. Called the chakravala (cyclic) method, it starts by choosing two relatively prime integers and , then composing the triple (that is, one which satisfies ) with the trivial triple to get the triple , which can be scaled down to When is chosen so that is an integer, so are the other two numbers in the triple. Among such , the method chooses one that minimizes and repeats the process. This method always terminates with a solution (proved by Joseph-Louis Lagrange in 1768). Bhaskara used it to give the solution x = , y = to the N = 61 case. Several European mathematicians rediscovered how to solve Pell's equation in the 17th century, apparently unaware that it had been solved almost five hundred years earlier in India. Pierre de Fermat found how to solve the equation and in a 1657 letter issued it as a challenge to English mathematicians. In a letter to Kenelm Digby, Bernard Frénicle de Bessy said that Fermat found the smallest solution for N up to 150 and challenged John Wallis to solve the cases N = 151 or 313. Both Wallis and William Brouncker gave solutions to these problems, though Wallis suggests in a letter that the solution was due to Brouncker. John Pell's connection with the equation is that he revised Thomas Branker's translation of Johann Rahn's 1659 book Teutsche Algebra into English, with a discussion of Brouncker's solution of the equation. Leonhard Euler mistakenly thought that this solution was due to Pell, as a result of which he named the equation after Pell. The general theory of Pell's equation, based on continued fractions and algebraic manipulations with numbers of the form was developed by Lagrange in 1766–1769. Solutions Fundamental solution via continued fractions Let denote the sequence of convergents to the regular continued fraction for . This sequence is unique. Then the pair solving Pell's equation and minimizing x satisfies x1 = hi and y1 = ki for some i. This pair is called the fundamental solution. Thus, the fundamental solution may be found by performing the continued fraction expansion and testing each successive convergent until a solution to Pell's equation is found. The time for finding the fundamental solution using the continued fraction method, with the aid of the Schönhage–Strassen algorithm for fast integer multiplication, is within a logarithmic factor of the solution size, the number of digits in the pair . However, this is not a polynomial-time algorithm because the number of digits in the solution may be as large as , far larger than a polynomial in the number of digits in the input value n. Additional solutions from the fundamental solution Once the fundamental solution is found, all remaining solutions may be calculated algebraically from expanding the right side, equating coefficients of on both sides, and equating the other terms on both sides. This yields the recurrence relations Concise representation and faster algorithms Although writing out the fundamental solution (x1, y1) as a pair of binary numbers may require a large number of bits, it may in many cases be represented more compactly in the form using much smaller integers ai, bi, and ci. For instance, Archimedes' cattle problem is equivalent to the Pell equation , the fundamental solution of which has digits if written out explicitly. However, the solution is also equal to where and and only have 45 and 41 decimal digits respectively. Methods related to the quadratic sieve approach for integer factorization may be used to collect relations between prime numbers in the number field generated by and to combine these relations to find a product representation of this type. The resulting algorithm for solving Pell's equation is more efficient than the continued fraction method, though it still takes more than polynomial time. Under the assumption of the generalized Riemann hypothesis, it can be shown to take time where N = log n is the input size, similarly to the quadratic sieve. Quantum algorithms Hallgren showed that a quantum computer can find a product representation, as described above, for
Egypt. The third system of stored-value phone cards are smart cards and use an embedded microchip. These were first launched on a large scale in 1986 in Germany by Deutsche Bundespost after three years of testing, and in France by France Télécom. Many other countries followed suit, including Ireland in 1990 and the UK circa 1994–1995, which phased out the old green Landis+Gyr cards in favor of the chip (smart) cards. The initial microchips were easy to hack, typically by scratching off the programming-voltage contact on the card, which rendered the phone unable to reduce the card's value after a call. But by the mid-to-late 1990s, highly secure technology aided the spread of chip phonecards worldwide. Remote memory systems Making a remote memory prepaid or calling card call requires the user to make two calls. It is necessary to dial an access telephone number to connect to the calling card system. There are several methods. One is via a toll-free number, with larger companies offering this internationally. Access through a local number has become increasingly popular in recent years. Toll-free calls are paid for by the recipient (the calling card company), which passes on the cost through higher call charges; total cost of a call to the user is often lower using a local number. When travelling through several local areas a toll-free service may be preferable. Once connected to the access number, the account is identified by keying in a PIN (the most popular method) or by swiping a card with embedded chip or magnetic stripe. After validation the balance remaining on the card may be announced, and the desired number may be keyed in. The available minutes may be announced, and the call is connected. Many cards make a verbal announcement if credit is running out. Prepaid or calling cards are usually much cheaper than other telephone services, particularly for travelers who do not have easy access to other services. Hotel telephones can be very expensive, particularly for long-distance calls. Cellular services are flexible, but may attract high roaming charges away from the home area. Telephone accounts symbolized by a card The second main technology of phonecards is remote memory, which uses a toll or toll-free access number to reach the database and check for balance on product. The first public prepaid remote memory phonecard was issued in the United States in December 1980 by Phone Line. As telecom industries around the world became deregulated, remote memory cards were issued in various countries. Remote memory phonecards can be used from any tone-mode phone and do not require special card readers. Since remote memory cards are more accessible and have lower costs, remote memory phone cards have proliferated. However, the utility of these cards is reduced by the large number of digits that need to be entered during usage. To call a long-distance number, the user first dials the local access number, then keys in the secret code, followed by the actual long-distance number. Based on the long-distance number entered, the time remaining on the card is announced, and the call is finally processed through. Remote memory phonecards are in essence text; requiring an access number, a unique PIN and instructions. Therefore, the instructions can be printed on virtually anything, or can be delivered via e-mail or the Internet. Currently many websites post phone card details through e-mail. Phone cards are available in most countries in retail stores, retail chains and commonly post offices or corner stores. In general, remote memory phonecards can be issued by any company and come in countless varieties. They can focus on calling to certain countries or regions and have specific features such as rechargeability, pinless dial, speed dial and more. Phone cards may have connection fees, taxes and maintenance fees, all influencing the rates. Accounts without a card (Virtual phonecards) Since the early 2000s calling card service providers have introduced calling accounts not associated with a physical card. Calling accounts can be purchased over the Internet using credit cards and are instantly delivered to the customer via e-mail. This e-mail contains the PIN and instructions for using the service. The service may be prepaid, or may take payment from a credit card or by direct debit. Some prepaid card companies allow accounts to be recharged online manually or automatically via a method called auto-top-up. Some virtual cards offer PINless Dialing, either by dialling a number unique to the customer, or by recognising the telephone number which originated the call by Caller ID and relating it to the appropriate account.	payphones, stored-value systems avoid the time lag and expense of communication with a central database, which would have been technically complex before the 1990s. There are several ways in which the value can be encoded on the card: The earliest system used a magnetic stripe as information carrier, similar to the technology of ATMs and key cards. The first magnetic strip phonecard, manufactured by SIDA, was issued in 1976 in Italy. The next technology used optical storage. Optical phonecards get their name from optical structure embossed inside the cards. This optical structure is heated and destroyed after use of the units. Visible marks are left on the top of the cards, so that the user can see the balance of remaining units. Optical cards were produced by Landis+Gyr and Sodeco from Switzerland and were popular early phonecards in many countries with first optical phonecards successfully introduced in 1977 in Belgium. Such technology was very secure and not easily hackable but chip cards phased out the optical phone cards around the world and the last Landis+Gyr factory closed in May 2006 when optical phonecards were still in use in few countries like Austria, Israel and Egypt. The third system of stored-value phone cards are smart cards and use an embedded microchip. These were first launched on a large scale in 1986 in Germany by Deutsche Bundespost after three years of testing, and in France by France Télécom. Many other countries followed suit, including Ireland in 1990 and the UK circa 1994–1995, which phased out the old green Landis+Gyr cards in favor of the chip (smart) cards. The initial microchips were easy to hack, typically by scratching off the programming-voltage contact on the card, which rendered the phone unable to reduce the card's value after a call. But by the mid-to-late 1990s, highly secure technology aided the spread of chip phonecards worldwide. Remote memory systems Making a remote memory prepaid or calling card call requires the user to make two calls. It is necessary to dial an access telephone number to connect to the calling card system. There are several methods. One is via a toll-free number, with larger companies offering this internationally. Access through a local number has become increasingly popular in recent years. Toll-free calls are paid for by the recipient (the calling card company), which passes on the cost through higher call charges; total cost of a call to the user is often lower using a local number. When travelling through several local areas a toll-free service may be preferable. Once connected to the access number, the account is identified by keying in a PIN (the most popular method) or by swiping a card with embedded chip or magnetic stripe. After validation the balance remaining on the card may be announced, and the desired number may be keyed in. The available minutes may be announced, and the call is connected. Many cards make a verbal announcement if credit is running out. Prepaid or calling cards are usually much cheaper than other telephone services, particularly for travelers who do not have easy access to other services. Hotel telephones can be very expensive, particularly for long-distance calls. Cellular services are flexible, but may attract high roaming charges away from the home area. Telephone accounts symbolized by a card The second main technology of phonecards is remote memory, which uses a toll or toll-free access number to reach the database and check for balance on product. The first public prepaid remote memory phonecard was issued in the United States in December 1980 by Phone Line. As telecom industries around the world became deregulated, remote memory cards were issued in various countries. Remote memory phonecards can be used from any tone-mode phone and do not require special card readers. Since remote memory cards are more accessible and have lower costs, remote memory phone cards have proliferated. However, the utility of these cards is reduced by the large number of digits that need to be entered during usage. To call a long-distance number, the user first dials the local access number, then keys in the secret code, followed by the actual long-distance number. Based on the long-distance number entered, the time remaining on the card is announced, and the call is finally processed through. Remote memory phonecards are in essence text; requiring an access number, a unique PIN and instructions. Therefore, the instructions can be printed on virtually anything, or can be delivered via e-mail or the Internet. Currently many websites post phone card details through e-mail. Phone cards are available in most countries in retail stores, retail chains and commonly post offices or corner stores. In general, remote memory phonecards can be issued by any company and come in countless varieties.
this line generally include support for floppy disk drives, keyboards and other computer peripherals. Some models can also be connected to an emulator and have software testing and debugging features. The CD-I player 700 series, which consists of the 740 model, the most advanced player and featuring an RS-232 port. It was only released in limited quantities. There also exist a number of hard-to-categorize models, such as the FW380i, an integrated mini-stereo and CD-i player; the 21TCDi30, a television with a built-in CD-i device; the CD-i/PC 2.0, a CD-i module with an ISA interface for IBM-compatible 486 PCs. Gallery Other manufacturers In addition to Philips, several manufacturers produced CD-i players some of which were still on sale years after Philips itself abandoned the format. Manufacturers included: Magnavox (a Philips subsidiary) made rebranded players for the American market. GoldStar / LG Electronics, the LG GDI-700 (c. 1997) was a professional player with a Motorola 68341 processor, faster than the Philips model. GoldStar had a portable player, including another small one without an LCD screen. Digital Video Systems Memorex Grundig Kyocera made the portable Pro 1000S model Maspro Denkoh released a GPS car navigation system with a built-in CD-i player, released in Japan in 1992. Saab Electric Sony produced two models branded Intelligent Discman, a hybrid home/portable CD-i player released in 1990-1991 for professional use only. NBS International Interactive Media (I2m) released in 1995 a CD-i PCI expansion card for 486 PCs, Pentium PCs, 68k-based Macintosh and PowerPC-based Macintosh computers Vobis Highscreen Manna Space branded CD-i models (based on Magnavox's or GoldStar's version of Philips CDI 450) were made for a Japanese travel agency with the same name in 1995. Bang & Olufsen, who produced a high-end television with a built-in CD-i device (Beocenter AV5) on the market from 1997-2001. Before the actual commercial debut of the CD-i format, some other companies had interest in building players and some made prototypes, but were never released – this includes Panasonic (who were originally a major backer of the format), Pioneer, JVC, Toshiba, Epson, Ricoh, Fujitsu, Samsung and Yamaha. In addition, Sanyo showed a prototype portable CD-i player in 1992. Hardware specifications TeleCD-i and CD-MATICS Recognizing the growing need among marketers for networked multimedia, Philips partnered in 1992 with Amsterdam-based CDMATICS to develop TeleCD-i (also TeleCD). In this concept, the CD-i player is connected to a network such as PSTN or Internet, enabling data-communication and rich media presentation. Dutch grocery chain Albert Heijn and mail-order company Neckermann were early adopters and introduced award-winning TeleCD-i applications for their home-shopping and home-delivery services. CDMATICS also developed the special Philips TeleCD-i Assistant and a set of software tools to help the worldwide multimedia industry to develop and implement TeleCD-i. TeleCD-i is the world's first networked multimedia application at the time of its introduction. In 1996, Philips acquired source code rights from CDMATICS. CD-Online Internet services on the CD-i devices were facilitated by the use of an additional hardware modem and "CD-Online" disc (renamed Web-i in the US), which Philips initially released in Britain in 1995 for $150 US. This service provided the CD-i with full internet access (with a 14.4k modem), including online shopping, email, and support for networked multiplayer gaming on select CD-i games. The service required a CD-i player with DV cartridge, and an "Internet Starter Kit" which initially retailed for £99.99. It was advertised as bringing "full Internet access to the living room on TV screens". Andy Stout, a writer for the official CD-i magazine, explained CD-Online: The CD-Online service went live in the UK on October 25, 1995 and in March 1996 in the Netherlands (for 399 guilders), and also released in Belgium. The system was reportedly scheduled to launch in the US as "Web-i" in August 1996. The domain cd-online.co.uk, which was used for the British CD-Online service, went offline in 2000. The Dutch domain cd-online.nl stopped updating too but remained online until 2007. Only one game was released that supported CD-Online, the first-person shooter game RAM Raid. Players from any country in the world could compete against each other as long as they had a copy of the game. Reception and market performance Philips had invested heavily in the CD-i format and system, and it was often compared with the Commodore CDTV as a single combination of computer, CD, and television. The product was touted as a single machine for home entertainment connected to a standard TV and controlled by a regular remote control – although the format was noted to have various non-entertainment business opportunities too, such as travel and tourism or the military. In 1990, Peugeot used CD-i for its point of sale application promoting its then-new 605 automobile, and it was also at the time used by fellow car manufacturer Renault for staff training programmes, and in Japan by the Ministry of Trade and Industry for an exhibition there. A Philips executive, Gaston Bastiaens, quoted in 1990 "CD-I will be 'the medium' for entertainment, education and information in the 90's.". Sony introduced its three portable CD-i players in June 1990, pitching them as "picture books with sound". The ambitious CD-i format had initially created much interest after its 1986 announcement, both in the west and in Japan, buoyed by the success of the CD. However, after repeated delays (hardware were first intended to be ready and shipped by Christmas 1987) interest was slowly lost. Electronic Arts for instance was enthusiastic about CD-i and formed a division for the development of video game titles on the format, but it was eventually halted with the intention of resuming when CD-i players would reach the market. The company eventually never resumed CD-i software development when it was released. The delay also gave more attention to the hyped Digital Video Interactive (DVI) in 1987, which demonstrated full screen, full motion video (FMV) using a compression chip on an IBM PC/AT computer. Amid the attention around its potential rival DVI, Philips and Sony decided to find a way to add full screen FMV abilities to the CD-i standard, causing further delay. Meanwhile, the Microsoft-backed CD-ROM standard was improving and solved certain video playback issues that were present on the CD-i – CD-ROM format products were already on the market by 1987. At the end, CD-ROM standard benefited from the CD-i and DVI mishaps, and by the time CD-i players for consumers were released in 1991, CD-ROM had already become known and established. Ron Gilbert commented in early 1990 "The CD-I specifications look great, but where are the machines? If they'd come out four years ago, they'd have been hot, but now they're behind the times." Another reason that led to fading interest pre-launch was the fact CD-i players would not launch with FMV but instead receive it later through a purchasable add-on cartridge (it was originally expected to come built-in) – as well as the obsolete Motorola processor, OS-9 software, and a launch price considered high. Although Philips had aggressively promoted their CD-i products in the U.S., by August 1993 Computer Gaming World reported that "skepticism persists about its long-term prospects" compared to other platforms like IBM PC compatibles, Apple Macintosh, and Sega Genesis. The magazine stated in January 1994 that despite Philips' new emphasis on games "CD-i is still not the answer for hardcore gamers", but the console "may yet surprise us all in the future". It recommended the CD-i with video cartridge for those needing to buy a new console as "The price is right and there is more software to support it", but 3DO Interactive Multiplayer was probably better for those who could wait a few months. The Electronic Entertainment August 1994 issue noted that the CD-i, along with the Atari Jaguar, neither have an "effective, let alone innovative" game library to compete against the then newly released Sega CD. After being outsold in the market by cheaper multimedia PCs, in 1994 Philips attempted to emphasize CD-i as a game playing machine, but this did not help the situation. An early 1995 review of the system in GamePro stated that "inconsistent game quality puts the CD-i at a disadvantage against other high-powered game producers." A late 1995 review in Next Generation criticized both Philips's approach to marketing the CD-i and the hardware itself ("The unit excels at practically nothing except FMV, and then only with the addition of a $200 digital video cartridge"). The magazine noted that while Philips had not yet officially discontinued the CD-i, it was dead for all intents and purposes, citing as evidence the fact that though Philips had a large booth at the 1995 Electronic Entertainment Expo, there was no CD-i hardware or software on display. Next Generation scored the console one out of five stars. Another trouble for Philips in 1995 was the formation of HDCD, which promised better quality video compared to Video CD's (VCD) MPEG-1 compression method – Philips had heavily promoted the CD-i's VCD playing capabilities. Philips Media consolidated its CD-i activities from its Los Angeles office in March 1996. It was reported in October 1996 that Philips was ready to "call it quits" in the American market. Sales In October 1994, Philips claimed an installed base of one million units for the CD-i worldwide. In 1996, The Wall Street Journal reported that total US sales amounted to 400,000 units. In the Netherlands, about 60,000 CD-i players were sold by the end of December 1994. Legacy Although extensively marketed by Philips, notably via infomercial, consumer interest in CD-i titles remained low. By 1994, sales of CD-i systems had begun to slow, and in 1998 the product line was dropped. Plans for a second generation CD-i system were certainly present and Argonaut Software was even designated to design chip sets for the successor to the CD-i. However, the then president Cor Boonstra saw no interest in the media area for Philips and so Philips sold everything, including the media subsidiary Polygram. The Dutch half of Philips Media was sold to Softmachine, which released The Lost Ride on the CD-i as the last product for the CD-i. Philips then also sold its French half of the gaming subsidiary, Philips Media BV, to French publisher Infogrames in 1997 along with the entire CD-i library. A CD-ROM add-on for the Super NES, which was announced for development with Nintendo in 1991, was never made. The last CD-i game was made by Infogrames, who released Solar Crusade in 1999. After its discontinuation, the CD-i was overwhelmingly panned by critics who blasted its graphics, games, and controls. Microsoft CEO Bill Gates admitted that initially he "was worried" about the CD-i due to Philips' heavy support for the device and its two-pronged attack on both the games console and PC markets, but that in retrospect, "It was a device that kind of basically got caught in the middle. It was a terrible game machine, and it was a terrible PC." The CD-i's various controllers were ranked the fifth worst video game controller by IGN editor Craig Harris. PC World ranked it as fourth on their list of "The 10 Worst Video Game Systems of All Time". Gamepro.com listed it as number four on their list of The 10 Worst-Selling Consoles of All Time. In 2008, CNET listed the system on its list of the worst game console(s) ever. In 2007, GameTrailers ranked the Philips CD-i as the fourth worst console of all time in its Top 10 Worst Console lineup. In later retrospective years, the CD-i has become (infamously) best known for its video games, particularly those from the Nintendo-licensed The Legend of Zelda series, considered by many to be of poor taste. Games that were most heavily criticized include Hotel Mario, Link: The Faces of Evil, Zelda: The Wand of Gamelon, and Zelda's Adventure. EGM's Seanbaby rated The Wand of Gamelon as one of the worst video games of all time. However, Burn:Cycle was positively received by critics and has often been held up as the standout title for the CD-i. See also CD-i Ready High Sierra Format 3DO Interactive Multiplayer MiniDisc CD-ROM Video CD Super NES CD-ROM Digital Video Interactive Commodore CDTV Pioneer LaserActive Sega CD FM Towns Tandy Video Information System NEC TurboDuo References External links Official Philips CD-I FAQ CD-i history	of Name That Tune) had Charlie O'Donnell as announcer. The Netherlands also released its version of Lingo on the CD-i in 1994. In 1993, American musician Todd Rundgren created the first music-only fully interactive CD, No World Order, for the CD-i. This application allows the user to completely arrange the whole album in their own personal way with over 15,000 points of customization. Dutch eurodance duo 2 Unlimited released a CD-i compilation album in 1994 called "Beyond Limits" which contains standard CD tracks as well as CD-i-exclusive media on the disc. CD-i has a series of learning games ("edutainment") targeted at children from infancy to adolescence. Those intended for a younger audience included Busytown, The Berenstain Bears and various others which usually had vivid cartoon-like settings accompanied by music and logic puzzles. By mid-1996 the U.S. market for CD-i software had dried up and Philips had given up on releasing titles there, but continued to publish CD-i games in Europe, where the system still held some popularity from a video gaming perspective. With the home market exhausted, Philips tried with some success to position the technology as a solution for kiosk applications and industrial multimedia. Some homebrew developers have released video games on the CD-i format in later years, such as Frog Feast (2005) and Super Quartet (2018). Player models CD-i compatible models were released (as of April 1995) in the U.S., Canada, Benelux, France, Germany, the UK, Japan, Singapore and Hong Kong. It was reported to be released further in Brazil, India and Australia in the "coming months", with plans to also introduce it in China, South Africa, Indonesia and the Philippines. Philips models In addition to consumer models, professional and development players were sold by Philips Interactive Media Systems and their VARs. The first CD-i system was produced by Philips in collaboration with Kyocera in 1988 – the Philips 180/181/182 modular system. Philips marketed several CD-i player models as shown below. The CD-i player 100 series, which consisted of the three-unit 180/181/182 professional system, first demonstrated at the CD-ROM Conference in March 1988. The CD-i player 200 series, which includes the 205, 210, and 220 models. Models in the 200 series were designed for general consumption, and were available at major home electronics outlets around the world. The Philips CDI 910 is the American version of the CDI 205, the most basic model in the series and the first Philips CD-i model, released in December 1991. Originally priced about $799, within a year's time the price dropped to $599. The CD-i player 300 series, which includes the 310, 350, 360, and 370 models. The 300 series consists of portable players designed for the professional market and not marketed to home consumers. A popular use was multimedia sales presentations such as those used by pharmaceutical companies to provide product information to physicians, as the devices could be easily transported by sales representatives. The CD-i player 400 series, which includes the 450, 470, 490 models. The 400 models are slimmed-down units aimed at console and educational markets. The CDI 450 player, for instance, is a budget model designed to compete with game consoles. In this version, an infrared remote controller is not standard but optional, as this model is more gaming-oriented. This series was introduced at CES Chicago in June 1994 and the 450 player retailed at ƒ 799 in the Netherlands. The CD-i player 500 series, which includes the 550 model, which was essentially the same as the 450 with an installed digital video cartridge. It was introduced at CES Chicago in June 1994. The CD-i player 600 series, which includes the 601, 602, 604, 605, 615, 660, and 670 models. The 600 series is designed for professional applications and software development. Units in this line generally include support for floppy disk drives, keyboards and other computer peripherals. Some models can also be connected to an emulator and have software testing and debugging features. The CD-I player 700 series, which consists of the 740 model, the most advanced player and featuring an RS-232 port. It was only released in limited quantities. There also exist a number of hard-to-categorize models, such as the FW380i, an integrated mini-stereo and CD-i player; the 21TCDi30, a television with a built-in CD-i device; the CD-i/PC 2.0, a CD-i module with an ISA interface for IBM-compatible 486 PCs. Gallery Other manufacturers In addition to Philips, several manufacturers produced CD-i players some of which were still on sale years after Philips itself abandoned the format. Manufacturers included: Magnavox (a Philips subsidiary) made rebranded players for the American market. GoldStar / LG Electronics, the LG GDI-700 (c. 1997) was a professional player with a Motorola 68341 processor, faster than the Philips model. GoldStar had a portable player, including another small one without an LCD screen. Digital Video Systems Memorex Grundig Kyocera made the portable Pro 1000S model Maspro Denkoh released a GPS car navigation system with a built-in CD-i player, released in Japan in 1992. Saab Electric Sony produced two models branded Intelligent Discman, a hybrid home/portable CD-i player released in 1990-1991 for professional use only. NBS International Interactive Media (I2m) released in 1995 a CD-i PCI expansion card for 486 PCs, Pentium PCs, 68k-based Macintosh and PowerPC-based Macintosh computers Vobis Highscreen Manna Space branded CD-i models (based on Magnavox's or GoldStar's version of Philips CDI 450) were made for a Japanese travel agency with the same name in 1995. Bang & Olufsen, who produced a high-end television with a built-in CD-i device (Beocenter AV5) on the market from 1997-2001. Before the actual commercial debut of the CD-i format, some other companies had interest in building players and some made prototypes, but were never released – this includes Panasonic (who were originally a major backer of the format), Pioneer, JVC, Toshiba, Epson, Ricoh, Fujitsu, Samsung and Yamaha. In addition, Sanyo showed a prototype portable CD-i player in 1992. Hardware specifications TeleCD-i and CD-MATICS Recognizing the growing need among marketers for networked multimedia, Philips partnered in 1992 with Amsterdam-based CDMATICS to develop TeleCD-i (also TeleCD). In this concept, the CD-i player is connected to a network such as PSTN or Internet, enabling data-communication and rich media presentation. Dutch grocery chain Albert Heijn and mail-order company Neckermann were early adopters and introduced award-winning TeleCD-i applications for their home-shopping and home-delivery services. CDMATICS also developed the special Philips TeleCD-i Assistant and a set of software tools to help the worldwide multimedia industry to develop and implement TeleCD-i. TeleCD-i is the world's first networked multimedia application at the time of its introduction. In 1996, Philips acquired source code rights from CDMATICS. CD-Online Internet services on the CD-i devices were facilitated by the use of an additional hardware modem and "CD-Online" disc (renamed Web-i in the US), which Philips initially released in Britain in 1995 for $150 US. This service provided the CD-i with full internet access (with a 14.4k modem), including online shopping, email, and support for networked multiplayer gaming on select CD-i games. The service required a CD-i player with DV cartridge, and an "Internet Starter Kit" which initially retailed for £99.99. It was advertised as bringing "full Internet access to the living room on TV screens". Andy Stout, a writer for the official CD-i magazine, explained CD-Online: The CD-Online service went live in the UK on October 25, 1995 and in March 1996 in the Netherlands (for 399 guilders), and also released in Belgium. The system was reportedly scheduled to launch in the US as "Web-i" in August 1996. The domain cd-online.co.uk, which was used for the British CD-Online service, went offline in 2000. The Dutch domain cd-online.nl stopped updating too but remained online until 2007. Only one game was released that supported CD-Online, the first-person shooter game RAM Raid. Players from any country in the world could compete against each other as long as they had a copy of the game. Reception and market performance Philips had invested heavily in the CD-i format and system, and it was often compared with the Commodore CDTV as a single combination of computer, CD, and television. The product was touted as a single machine for home entertainment connected to a standard TV and controlled by a regular remote control – although the format was noted to have various non-entertainment business opportunities too, such as travel and tourism or the military. In 1990, Peugeot used CD-i for its point of sale application promoting its then-new 605 automobile, and it was also at the time used by fellow car manufacturer Renault for staff training programmes, and in Japan by the Ministry of Trade and Industry for an exhibition there. A Philips executive, Gaston Bastiaens, quoted in 1990 "CD-I will be 'the medium' for entertainment, education and information in the 90's.". Sony introduced its three portable CD-i players in June 1990, pitching them as "picture books with sound". The ambitious CD-i format had initially created much interest after its 1986 announcement, both in the west and in Japan, buoyed by the success of the CD. However, after repeated delays (hardware were first intended to be ready and shipped by Christmas 1987) interest was slowly lost. Electronic Arts for instance was enthusiastic about CD-i and formed a division for the development of video game titles on the format, but it was eventually halted with the intention of resuming when CD-i players would reach the market. The company eventually never resumed CD-i software development when it was released. The delay also gave more attention to the hyped Digital Video Interactive (DVI) in 1987, which demonstrated full screen, full motion video (FMV) using a compression chip on an IBM PC/AT computer. Amid the attention around its potential rival DVI, Philips and Sony decided to find a way to add full screen FMV abilities to the CD-i standard, causing further delay. Meanwhile, the Microsoft-backed CD-ROM standard was improving and solved certain video playback issues that were present on the CD-i – CD-ROM format products were already on the market by 1987. At the end, CD-ROM standard benefited from
moth (Biston betularia) is a temperate species of night-flying moth.It is mostly found in the northern hemisphere in places like Asia, Europe and North America. Peppered moth evolution is an example of population genetics and natural selection. The caterpillars of the peppered moth not only mimic the form but also the colour of a twig. Recent research indicates that the caterpillars can sense the twig's colour with their skin and match their body colour to the background to protect themselves from predators. Description The wingspan ranges from 45 mm to 62 mm (median 55 mm). It is relatively stout-bodied, with forewings relatively narrow-elongate. The wings are white, "peppered" with black, and with more-or-less distinct cross lines, also black. These transverse wing lines and "peppered" maculation (spotting) can also, in rare instances, be gray or brown; the spotting pattern, in particularly very rare cases, is sometimes a combination of brown and black/gray. The black speckling varies in amount, in some examples it is almost absent, whilst in others it is so dense that the wings appear to be black sprinkled with white. The antennae of males are strongly bipectinate. Prout (1912–16) gives an account of the forms and congeners. Distribution Biston betularia is found in China (Heilongjiang, Jilin, Inner Mongolia, Beijing, Hebei, Shanxi, Shandong, Henan, Shaanxi, Ningxia, Gansu, Qinghai, Xinjiang, Fujian, Sichuan, Yunnan, Tibet), Russia, Mongolia, Japan, North Korea, South Korea, Nepal, Kazakhstan, Kyrgyzstan, Turkmenistan, Georgia, Azerbaijan, Armenia, Europe and North America. Ecology and life cycle In Great Britain and Ireland, the peppered moth is univoltine (i.e., it has one generation per year), whilst in south-eastern North America it is bivoltine (two generations per year). The lepidopteran life cycle consists of four stages: ova (eggs), several larval instars (caterpillars), pupae, which overwinter live in the soil, and imagines (adults). During the day, the moths typically rest on trees, where they are preyed on by birds. The caterpillar is a twig mimic, varying in colour between green and brown. On a historical note, it was one of the first animals to be identified as being camouflaged with countershading to make it appear flat (shading being the main visual cue that makes things appear solid), in a paper by Edward Bagnall Poulton in 1887. Research indicates that the caterpillars can sense the twig's colour with their skin and match their body colour to the background to protect themselves from predators, an ability to camouflage themselves also found in cephalopods, chameleons and some fish, although this colour change is rather slower in the caterpillars. It goes into the soil late in the season, where it pupates in order to spend the winter. The imagines emerge from the pupae between late May and August, the males slightly before the females (this is common and expected from sexual selection). They emerge late in the day and dry their wings before flying that night. The males fly every night of their lives in search of females, whereas the females only fly on the first night. Thereafter, the females release pheromones to attract males. Since the pheromone is carried by the wind, males tend to travel up the concentration gradient, i.e., toward the source. During flight, they are subject to predation by bats. The males guard the female from other males until she lays the eggs. The female lays about 2,000 pale-green ovoid eggs about 1 mm in length into crevices in bark with her ovipositor. Resting behaviour A mating pair or a lone individual will spend the day hiding from predators, particularly birds. In the case of the former, the male stays with the female to ensure paternity. The best evidence for resting positions is given by data collected by the peppered moth researcher Michael Majerus, and it is given in the accompanying charts. These data were originally published in Howlett and Majerus (1987), and an updated version published in Majerus (1998), who concluded that the moths rest in the upper part of the trees. Majerus notes: Creationist critics of the peppered moth have often pointed to a statement made by Clarke et al. (1985): "... In 25 years we have only found two betularia on the tree trunks or walls adjacent to our traps, and none elsewhere". The reason now seems obvious. Few people spend their time looking for moths up in the trees. That is where peppered moths rest by day. From their original data, Howlett and Majerus (1987) concluded that peppered moths generally rest in unexposed positions, using three main types of site. Firstly, a few inches below a branch-trunk joint on a tree trunk where the moth is in shadow; secondly, on the underside of branches and thirdly on foliate twigs. The above data would appear to support this. Further support for these resting positions is given from experiments watching captive moths taking up resting positions in both males (Mikkola, 1979; 1984) and females (Liebert and Brakefield, 1987). Majerus, et al., (2000) have shown that peppered moths are cryptically camouflaged against their backgrounds when they rest in the boughs of trees. It is clear that in human visible wavelengths, typica are camouflaged against lichens and carbonaria against plain bark. However, birds are capable of seeing ultraviolet light that humans cannot see. Using an ultraviolet-sensitive video camera, Majerus et al. showed that	to a statement made by Clarke et al. (1985): "... In 25 years we have only found two betularia on the tree trunks or walls adjacent to our traps, and none elsewhere". The reason now seems obvious. Few people spend their time looking for moths up in the trees. That is where peppered moths rest by day. From their original data, Howlett and Majerus (1987) concluded that peppered moths generally rest in unexposed positions, using three main types of site. Firstly, a few inches below a branch-trunk joint on a tree trunk where the moth is in shadow; secondly, on the underside of branches and thirdly on foliate twigs. The above data would appear to support this. Further support for these resting positions is given from experiments watching captive moths taking up resting positions in both males (Mikkola, 1979; 1984) and females (Liebert and Brakefield, 1987). Majerus, et al., (2000) have shown that peppered moths are cryptically camouflaged against their backgrounds when they rest in the boughs of trees. It is clear that in human visible wavelengths, typica are camouflaged against lichens and carbonaria against plain bark. However, birds are capable of seeing ultraviolet light that humans cannot see. Using an ultraviolet-sensitive video camera, Majerus et al. showed that typica reflect ultraviolet light in a speckled fashion and are camouflaged against crustose lichens common on branches, both in ultraviolet and human-visible wavelengths. However, typica are not as well camouflaged against foliose lichens common on tree trunks; though they are camouflaged in human wavelengths, in ultraviolet wavelengths, foliose lichens do not reflect ultraviolet light. During an experiment in Cambridge over the seven years 2001–2007 Majerus noted the natural resting positions of peppered moths, and of the 135 moths examined over half were on tree branches, mostly on the lower half of the branch, 37% were on tree trunks, mostly on the north side, and only 12.6% were resting on or under twigs. Polymorphism Introduction on forms There are several melanic and non-melanic morphs of the peppered moth. These are controlled genetically. A particular colour morph can be indicated in a standard way by following the species name in the form "morpha morph name". The use of "form" in the method of Biston betularia f. formname in detailing these variations is also a widespread practice. These forms are often accidentally elevated to subspecies status when they appear in literature. Not adding the "f." (forma) or morpha implies that the taxon is a subspecies instead of a form, as in Biston betularia carbonaria instead of Biston betularia f. carbonaria. Rarely, forms have been elevated to species status, as in Biston carbonaria. Either of these two circumstances might lead to the erroneous belief that speciation was involved in the observed evolution of the peppered moth. This is not the case; individuals of each morph interbreed and produce fertile offspring with individuals of all other morphs; hence there is only one peppered moth species. By contrast, different subspecies of the same species can theoretically interbreed with one another and will produce fully fertile and healthy offspring, but in practice do not, as they live in different regions or reproduce in different seasons. Full-fledged species are either unable to produce fertile and healthy offspring, or do not recognize each other's courtship signals, or both. European breeding experiments have shown that in Biston betularia betularia, the allele for melanism producing morpha carbonaria is controlled by a single locus. The melanic allele is dominant to the non-melanic allele. This situation is, however, somewhat complicated by the presence of three other alleles that produce indistinguishable morphs of morpha medionigra. These are of intermediate dominance, but this is not complete (Majerus, 1998). Form names In continental Europe, there are three morphs: the white morph typica (syn. morpha/f. betularia), the dark melanistic morph carbonaria (syn. doubledayaria), and an intermediate form medionigra. In Britain, the typical white morph is known as typica, the melanic morph is carbonaria, and the intermediate phenotype is named insularia. In North America, the melanic black morph is morpha swettaria. In Biston betularia cognataria, the melanic allele (producing morpha swettaria) is similarly dominant to the non-melanic allele. There are also some intermediate morphs. In Japan, no melanic morphs have been recorded; they are all morpha typica. Evolution The evolution of the peppered moth over the last two hundred years has been studied in detail. At the start of this period, the vast majority of peppered moths had light coloured wing patterns which effectively camouflaged them against the light-coloured trees and lichens upon which they rested. However, due to widespread pollution during the Industrial Revolution in England, many of the lichens died out, and the trees which peppered moths rested on became blackened by soot, causing most of the light-coloured moths, or typica, to die off due to predation. At the same time, the dark-coloured, or melanic, moths, carbonaria, flourished because they could hide on the darkened trees. Since then, with improved environmental standards, light-coloured peppered moths have again become common, and the dramatic change in the peppered moth's population has remained a subject of much interest and study. This has led to the coining of the term "industrial melanism" to refer to the genetic darkening of species in response to pollutants. As a result of the relatively simple and easy-to-understand circumstances of the adaptation, the peppered moth has become a common example used in explaining or demonstrating natural selection to laypeople and classroom students through simulations. The first carbonaria morph was recorded by
were a line of IBM RS/6000 workstations in September 1993. Many Macintosh application developers used these machines for development of the initial PowerPC ports of their products, as Macintosh-based PowerPC development tools were not ready. The PowerPC 603 (which focused on lowering power usage) and 604 (which focused on high performance) projects were also underway at the same time. In July 1992, the decision was made to scale back the ambition of the initial system software release; instead of attempting to create a completely new kernel, Apple focused on producing a version of System 7 where portions of the existing Macintosh Toolbox ROM were rewritten to use native PowerPC code instead of emulating a 680x0. This provided a significant performance boost for certain highly utilized parts of the operating system, particularly QuickDraw. The first public demonstration of the new Power Macintosh — specifically, a prototype of what would become the Power Macintosh 6100 – was at an Apple Pacific sales meeting in Hawaii in October 1992. The demo was a success, and in the following months, the product plan expanded to include three models: the entry-level 6100, a mid-range 7100 housed in the Macintosh IIvx's desktop case, and a high-end 8100 based on the Quadra 800's mini-tower case. A fourth project, the Macintosh Processor Upgrade Card, was started in July 1993 with the goal of providing a straightforward upgrade path to owners of Centris- and Quadra-based Macintosh computers. The importance of this was especially significant for the Quadra 700, 900 and 950, which were not going to receive full logic board replacements. Computers upgraded in this fashion received new names such as "Power Macintosh Q650" and "Power Macintosh 900". Release and reception (1994-1995) The original plan was to release the first Power Macintosh machine on January 24, 1994, exactly ten years after the release of the first Macintosh. Ian Diery, who was EVP and general manager of the Personal Computer Division at the time, moved the release date back to March 14 in order to give manufacturing enough time to build enough machines to fill the sales channels, and to ensure that the Macintosh Processor Upgrade Card would be available at the same time. This was a departure from prior practice at Apple; they had typically released upgrade packages months after the introduction of new Macintoshes. The Power Macintosh was formally introduced at the Lincoln Center for the Performing Arts in Manhattan on March 14. Pre-orders for the new Power Macintosh models were brisk, with an announced 150,000 machines already having been sold by that date. MacWorld's review of the 6100/60 noted that "Not only has Apple finally regained the performance lead it lost about eight years ago when PCs appeared using Intel's 80386 CPU, but it has pushed far ahead." Performance of 680x0 software is slower due to the emulation layer, but MacWorld's benchmarks showed noticeably faster CPU, disk, video and floating point performance than the Quadra 610 it replaced. By January 1995, Apple had sold 1 million Power Macintosh systems. Speed-bumped versions of the Power Macintosh line were introduced at the beginning of 1995, followed in April by the first PowerPC 603 models: an all-in-one model called the Power Macintosh 5200 LC and a replacement for the Quadra 630 called the Power Macintosh 6200. Performa variants of these machines were sold as well, continuing the practice of re-branding other Macintosh models for sale in department stores and big-box electronics retailers. While the 5200 LC was well-received by critics for its design, performance, and cost, both it and the 6200 suffered from stability issues (and in the case of the 5200, display issues as well) that could only be solved by bringing the machine to an Apple dealer for replacement parts. By mid-1995, the burgeoning Power Macintosh line had all but completely supplanted every prior Macintosh line, with only the high-end Quadra 950 and two low-cost education models (the all-in-one Macintosh LC 580 and desktop LC 630) remaining in production. The competitive marketplace for "accelerator cards" that had existed for earlier Macintosh systems largely disappeared due to the comparatively low price of Apple's Macintosh Processor Upgrade Card (US$600). DayStar Digital sold upgrade cards for the IIci and various Quadra models, and full motherboard replacements were available from Apple as well. Macintosh clones from companies like DayStar Digital and Power Computing were also coming to the market at this time, undercutting Apple's prices. Transition to standardized hardware (1995-1999) When the Power Macintosh was introduced, it included the same internal and external expansion connections as other Macintosh models, all of which (save for audio input and output) were either wholly proprietary to, or largely exclusive to Apple computers. Over the next five years, Apple replaced all these ports with industry-standard connectors. The first generation of Power Macintoshes had shipped with NuBus, but by the end of 1993 it was becoming clear that Intel's PCI bus was going to be the widely adopted future of internal expansion. Apple's position as a relatively small player in the larger personal computer market meant that few device manufacturers invested in creating both NuBus- and PCI-compatible versions of their cards. The first PCI-based system was the range-topping Power Macintosh 9500, introduced in May 1995. This was followed shortly afterwards by the introduction of the "Power Surge" line of second-generation Power Macintosh systems – the Power Macintosh 7200, 7500 and 8500. The 8500 and 9500 were built around the new PowerPC 604, offering speeds starting at 120 MHz. InfoWorld's review of the 8500 showed a speed improvement in their "business applications suite" benchmark from 10 minutes with the 8100/100, to 7:37 for the 8500/120. They also noted that the 8500 runs an average of 24 to 44 percent faster than a similarly-clocked Intel Pentium chip, increasing to double on graphics and publishing tasks. The transition to PCI continued into 1996, with the introduction of the all-in-one 5400, desktop 6300/160 (usually sold as a Performa 6360), and mini-tower 6400 models. The success of the Macintosh clone market also prompted Apple to produce its own inexpensive machine using parts and production techniques that were common in both the clone market and the Wintel desktop market at the time. The Power Macintosh 4400 (sold as a 7220 in Asia and Australia) employed bent sheet metal instead of plastic for its case internals, and included a standard ATX power supply. Alongside the transition to PCI, Apple began a gradual transition away from SCSI hard disks to IDE as a cost-saving measure, both for themselves and for users who wanted to upgrade their hard drives. The low-end 5200 and 6200 were the first to adopt IDE internal drives, though Apple's proprietary 25-pin external SCSI connector remained. The beige Power Macintosh G3 models being the last to include SCSI drives as standard, and it was the last Macintosh to include the external SCSI connector. When the Power Macintosh G3 (Blue and White) was introduced in early 1999, the port was replaced by two FireWire 400 ports. The Blue and White G3 was also the last Macintosh to include Apple Desktop Bus ports, a proprietary technology created by Steve Wozniak to connect keyboards, mice and software protection dongles such as those from Avid Technology. Two USB ports were also included, making this the only Power Macintosh to include both ADB and USB. Another port that was retired during this time is the Apple Attachment Unit Interface. This was	ports. The Blue and White G3 was also the last Macintosh to include Apple Desktop Bus ports, a proprietary technology created by Steve Wozniak to connect keyboards, mice and software protection dongles such as those from Avid Technology. Two USB ports were also included, making this the only Power Macintosh to include both ADB and USB. Another port that was retired during this time is the Apple Attachment Unit Interface. This was a proprietary version of the industry-standard Attachment Unit Interface connector for 10BASE5 Ethernet that Apple had created to avoid confusion with the 15-pin connector that Apple used for connecting external displays. The AAUI port required a costly external transceiver to connect to a network. By the early 1990s, the networking industry was coalescing around the 10BASE-T connector, leading Apple to include this port alongside AAUI in mid-1995, starting with the Power Macintosh 9500. The Power Macintosh G3 excluded the AAUI port. The Power Mac G4 (AGP Graphics) was released in the second half of 1999; it was the first Power Macintosh to include only industry-standard internal and external expansion. For some years afterwards, a number of third parties created dongles that provided backwards compatibility to users of newer Power Mac systems with old hardware. This included companies like Griffin Technology, MacAlly Peripherals, Rose Electronics and many others. In some cases, these companies produced adapters that matched the aesthetic design of the Power Mac. Industrial design and the Megahertz Myth (1999-2002) Shortly after Steve Jobs' return to Apple in 1997, Jony Ive was appointed senior vice president of industrial design. Building on the critical and commercial success of the iMac, Ive and his team created an entirely new case design for the Power Macintosh G3, combining many of the aesthetic principles of the iMac (curves, translucent plastics, use of color) with the ease-of-access characteristics of the company's popular "Outrigger" Macintosh models from previous years. The result was the Power Macintosh G3 (Blue and White), a machine that received considerable plaudits from reviewers, including PC Magazine's Technical Excellence Award for 1999. "The Power Mac provides the fastest access to the insides of a computer we've ever seen," they wrote. "Just lift a handle and a hinged door reveals everything inside." This case design, code-named "El Capitan", was retained through the entire lifetime of the Power Mac G4. The introduction of the Blue and White G3 mini-tower also marked the end of the desktop and all-in-one Power Macintosh case designs, the latter being replaced by the iMac. A second model called the Power Mac G4 Cube was introduced in 2000, which fitted the specifications of a mid-range Power Mac G4 into a cube less than 9" in each axis. This model was on sale for about a year before being discontinued, and was not considered a sales success (150,000 units were sold, about one-third of Apple's projections), but the distinctive design of both the computer and its accompanying Harman Kardon speakers prompted the Museum of Modern Art in New York City to retain them in their collection. The PowerPC chips in the G3 and G4 became a central part of Apple's branding and marketing for the Power Macintosh. For example, the Blue and White G3 features the letters "G3" on the side that are fully one-third the height of the entire case, a significant departure from the small labels typically used on prior Macintosh computers. And when the Power Mac G4 was introduced, print ads included pictures of the G4 chip and mentioned its AltiVec instruction set by its own marketing name, "Velocity Engine". A related element of Apple's marketing strategy, especially after mid-2001, was to highlight what they described as the "Megahertz myth", challenging the belief that a processor's clock speed is directly correlated with performance. This had become important with the introduction of Intel's Pentium 4, which featured significantly higher clock speeds than competing chips from Sun, IBM, and AMD, but without a corresponding performance benefit. The company's public presentations -- Stevenotes in particular—often featured lengthy segments pitting a high-powered Compaq or Dell computer against the Power Macintosh in a series of benchmarks and scripted tasks, usually in Adobe Photoshop. These presentations often showed the Power Macintosh besting Intel's Pentium chips by margins significantly exceeding 50%, but independent benchmarks did not bear this out. InfoWorld reviewer Jennifer Plonka reported that the 400 MHz G3 was 11% slower than a comparably-specced Pentium II-450 in an Office applications suite test, while Photoshop 5.0 was faster by 26%. And in 2003, Maximum PC ran a variety of gaming, Photoshop and LightWave 3D benchmarks, and reported that the Dual 1.25 GHz G4 system was about half the speed of a dual-processor Intel Xeon Prestonia 2.8 GHz system. A related criticism leveled at Power Mac systems from this time, particularly the G4 Mirrored Drive Doors, was the increased fan noise level compared to older systems. The Power Mac G5 and the end of Power (2003-2006) By the time the Power Mac G5 was unveiled at Apple's Worldwide Developers Conference in July 2003, Apple's desktop range had fallen significantly behind competing computers in performance. The G5 closed much of this gap by moving to the PowerPC 970 processor with clock speeds up to 2.0 GHz, and a full 64-bit architecture. It also introduced a significantly revised enclosure design, replacing the use of plastics with anodized aluminum alloy. Reviews were generally positive. InfoWorld described the G5 as "Apple's best work yet", and said it "delivers on the present need for rapid computing, deep multitasking, and responsive user interfaces — as well as the future need for mainstream computers that rapidly process and analyze massive data sets." PC Magazine again awarded the Power Mac G5 with its Award for Technical Excellence for 2003. However, the G5's heavy weight (10 pounds more than the previous year's Quicksilver Power Mac G4), limited internal expansion options, issues with ground loop, and noise in the single-processor models' power supply units resulted in significant criticism of the product. Apple also continued to make unsubstantiated performance claims about the new Power Mac. This resulted in the Advertising Standards Authority for the United Kingdom banning Apple from using the phrase "the world's fastest, most powerful personal computer" to describe the Power Mac G5 after independent tests carried out by the Broadcast Advertising Clearance Centre determined the claim to be false. Another claim made by Steve Jobs at the 2003 Worldwide Developers Conference was that the company would be selling a 3 GHz G5 by mid-2004; this never happened. Three generations of Power Mac G5 were released before it was discontinued during the Mac transition to Intel processors. The announcement of the transition came in mid-2005, but the third generation of G5 systems was introduced towards the end of 2005. Most notably in this generation was the introduction of a Quad-core 2.5 GHz system. Not only was this the first Apple computer with four processing cores, it was the first to incorporate PCI Express instead of PCI-X for internal expansion. It also required an IEC 60320 C19 power connector that was more common on rackmounted server hardware, instead of the industry-standard C13 connector used with personal computers. The official end to the Power Macintosh line came at the 2006 Worldwide Developers Conference, where Phil Schiller introduced its replacement, the Mac Pro. The G5's enclosure design was retained for the Mac Pro and continued to be used for seven more years, making it among the longest-lived designs in Apple's history. Models The Power Macintosh models can be broadly classified into two categories, depending on whether they were released before or after Apple introduced its "four quadrant" product strategy in 1998. Before the introduction of the Power Macintosh G3 (Blue and White) in 1999, Apple had shipped Power Macintosh-labelled machines in nine different form factors, some of which were carry-overs from pre-PowerPC product lines, such as the Quadra/Centris 610 and the IIvx. This was reduced to one model in the new product strategy, with the exception of the Power Mac G4 Cube in 2000 and 2001. 1994-1997 Apple named Power Macintosh models from this period after the first pre-PowerPC model of Macintosh to use a particular form factor, followed by a slash and the speed of the CPU. For example, the Power Macintosh 6300/120 uses the Quadra 630's form factor and has a CPU. Machines with "AV" in their name denote variants that include extended audio-video capabilities. Machines with "PC Compatible" in their name include a separate card with an x86-compatible CPU; these models are therefore capable of running MS-DOS and Microsoft Windows applications, typically Windows 3.1. Machines with "MP" in their name denote machines that include two CPUs. These early models had two distinct generations. The first generation uses the PowerPC 601 and 603 processors and used the old NuBus expansion slots, while the second generation uses the faster 603e, 604 and 604e chips as well as industry-standard PCI expansion slots. The second generation also makes use of Open Firmware, allowing them to more easily boot alternate operating systems (including OS X via XPostFacto), though use of various hacks was still necessary. Power Macintosh 4400 The Power Macintosh 4400 is a desktop case with a height of , suitable for horizontal placement with a monitor on top. Power Macintosh 4400/160, 200, 200 (PC Compatible) (Marketed as the Power Macintosh 7220 in some regions) Power Macintosh 5200 The Power Macintosh 5200 is an all-in-one form factor with specifications and internal designs similar to the Quadra 630. Collectively these machines are sometimes referred to as the "Power Macintosh/Performa 5000 series". Power Macintosh 5200/75 LC Power Macintosh 5260/100, 120 Power Macintosh 5300/100 LC Power Macintosh 5400/120, 180, 200 Power Macintosh 5500/225, 250 Centris 610 The Centris 610 form factor is a low-profile "pizza-box" design with a height of , intended to be placed on a desktop with a monitor on top. Power Macintosh 6100/60, 60AV, 66, 66AV, 66 (DOS Compatible) Quadra 630 The Quadra 630 form factor is a horizontally-oriented design with a height of , suitable for placing a monitor on top. Power Macintosh 6200/75 Power Macintosh 6300/120, 160 Performa 6400 The Performa 6400 form factor is a mini-tower design, suitable for being placed beside a monitor. Power Macintosh 6400/180, 200 Power Macintosh 6500/225, 250, 275, 300 Power Macintosh 7100 The IIvx form factor is a horizontally-oriented desktop form factor with a height of , suitable for placing a monitor on top. Power Macintosh 7100/66, 66AV, 80, 80AV Power Macintosh 7500 The Power Macintosh 7500 form factor is a horizontally-oriented desktop design with a height of , suitable for placing a monitor on top. Power Macintosh 7200/75, 90, 120 (PC), 200 (PC) Power Macintosh 7300/166, 180 (PC), 200 Power Macintosh 7500/100 Power Macintosh 7600/120, 132, 200 Quadra 800 The Quadra 800 form factor is a mini-tower design, with a width of . Power Macintosh 8100/80, 80AV, 100, 100AV, 110, 110AV Power Macintosh 8115/110 Power Macintosh 8200/100, 120 Power Macintosh 8500/120, 132, 150, 180 Power Macintosh 8515/120 Power Macintosh 9600 The Power Macintosh 9600 form factor is a mini-tower design with a width of . Power Macintosh 8600/200, 250, 300 Power Macintosh 9500/120, 132, 150, 180MP, 200 Power Macintosh 9515/132 Power Macintosh 9600/200, 200MP, 233, 300, 350 1997-2006 Starting with the Power Macintosh G3, Apple changed its product naming to include the generation of PowerPC CPU, with the name of the form factor or a key feature afterwards in brackets. The all-in-one models would eventually be spun off into the iMac line, whilst the compact form factor models would be spun off into the Mac Mini. Power Macintosh G3 Power Macintosh G3 Desktop Power Macintosh G3 Mini Tower Power Macintosh G3 All-In-One Power Macintosh G3 Blue and White Power Mac G4 Power Mac G4 PCI Graphics Power Mac G4 AGP Graphics Power Mac G4 Gigabit Ethernet Power Mac G4 Digital Audio Power Mac G4 Quicksilver Power Mac G4 Quicksilver 2002 Power Mac G4 Mirrored Drive Doors Power Mac G4 Mirrored Drive Doors FW800 Power Mac G4 Mirrored Drive Doors 2003 Power Mac G4 Cube Power Mac G5 The Power Mac G5's name was changed to incorporate the time period in which the model was released. Power Mac G5 (original) Power Mac G5 June 2004 Power Mac G5 Late 2004 Power Mac G5 Early 2005 Power Mac G5 Late 2005 Naming The Power Mac brand name was used for Apple's high-end tower style computers, targeted primarily at businesses and creative professionals, in differentiation to their more compact "iMac" line (intended for home use) and the "eMac" line (for the
islands, and a symmetry around the midpoint of dominant Cs and As on one side and Gs and Ts on the other. A motif with the consensus sequence of TCTCGCGAGA, also called the CGCG element, was recently shown to drive PolII-driven bidirectional transcription in CpG islands. CCAAT boxes are common, as they are in many promoters that lack TATA boxes. In addition, the motifs NRF-1, GABPA, YY1, and ACTACAnnTCCC are represented in bidirectional promoters at significantly higher rates than in unidirectional promoters. The absence of TATA boxes in bidirectional promoters suggests that TATA boxes play a role in determining the directionality of promoters, but counterexamples of bidirectional promoters do possess TATA boxes and unidirectional promoters without them indicates that they cannot be the only factor. Although the term "bidirectional promoter" refers specifically to promoter regions of mRNA-encoding genes, luciferase assays have shown that over half of human genes do not have a strong directional bias. Research suggests that non-coding RNAs are frequently associated with the promoter regions of mRNA-encoding genes. It has been hypothesized that the recruitment and initiation of RNA polymerase II usually begins bidirectionally, but divergent transcription is halted at a checkpoint later during elongation. Possible mechanisms behind this regulation include sequences in the promoter region, chromatin modification, and the spatial orientation of the DNA. Subgenomic A subgenomic promoter is a promoter added to a virus for a specific heterologous gene, resulting in the formation of mRNA for that gene alone. Many positive-sense RNA viruses produce these subgenomic mRNAs (sgRNA) as one of the common infection techniques used by these viruses and generally transcribe late viral genes. Subgenomic promoters range from 24 nucleotide (Sindbis virus) to over 100 nucleotides (Beet necrotic yellow vein virus) and are usually found upstream of the transcription start. Detection A wide variety of algorithms have been developed to facilitate detection of promoters in genomic sequence, and promoter prediction is a common element of many gene prediction methods. A promoter region is located before the -35 and -10 Consensus sequences. The closer the promoter region is to the consensus sequences the more often transcription of that gene will take place. There is not a set pattern for promoter regions as there are for consensus sequences. Evolutionary change Changes in promoter sequences are critical in evolution as indicated by the relatively stable number of genes in many lineages. For instance, most vertebrates have roughly the same number of protein-coding genes (about 20,000) which are often highly conserved in sequence, hence much of evolutionary change must come from changes in gene expression. De novo origin of promoters Given the short sequences of most promoter elements, promoters can rapidly evolve from random sequences. For instance, in E. coli, ~60% of random sequences can evolve expression levels comparable to the wild-type lac promoter with only one mutation, and that ~10% of random sequences can serve as active promoters even without evolution. Binding The initiation of the transcription is a multistep sequential process that involves several mechanisms: promoter location, initial reversible binding of RNA polymerase, conformational changes in RNA polymerase, conformational changes in DNA, binding of nucleoside triphosphate (NTP) to the functional RNA polymerase-promoter complex, and nonproductive and productive initiation of RNA synthesis. The promoter binding process is crucial in the understanding of the process of gene expression. Location Although RNA polymerase holoenzyme shows high affinity to non-specific sites of the DNA, this characteristic does not allow us to clarify the process of promoter location. This process of promoter location has been attributed to the structure of the holoenzyme to DNA and sigma 4 to DNA complexes. Diseases associated with aberrant function Most diseases are heterogeneous in cause, meaning that one "disease" is often many different diseases at the molecular level, though symptoms exhibited and response to treatment may be identical. How diseases of different molecular origin respond to treatments is partially addressed in the discipline of pharmacogenomics. Not listed here are the many kinds of cancers involving aberrant transcriptional regulation owing to creation of chimeric genes through pathological chromosomal translocation. Importantly, intervention in the number or structure of promoter-bound proteins is one key to treating a disease without affecting expression of unrelated genes sharing elements with the target gene. Some genes whose change is not desirable are capable of influencing the potential of a cell to become cancerous. CpG islands in promoters In humans, about 70% of promoters located near the transcription start site of a gene (proximal promoters) contain a CpG island. CpG islands are generally 200 to 2000 base pairs long, have a C:G base pair content >50%, and have regions of DNA where a cytosine nucleotide is followed by a guanine nucleotide and this occurs frequently in the linear sequence of bases along its 5' → 3' direction. Distal promoters also frequently contain CpG islands, such as the promoter of the DNA repair gene ERCC1, where the CpG island-containing promoter is located about 5,400 nucleotides upstream of the coding region of the ERCC1 gene. CpG islands also occur frequently in promoters for functional noncoding RNAs such as microRNAs. Methylation of	or can have a function in and of itself, such as tRNA or rRNA. Promoters are located near the transcription start sites of genes, upstream on the DNA (towards the 5' region of the sense strand). Promoters can be about 100–1000 base pairs long, the sequence of which is highly dependent on the gene and product of transcription, type or class of RNA polymerase recruited to the site, and species of organism. Overview For transcription to take place, the enzyme that synthesizes RNA, known as RNA polymerase, must attach to the DNA near a gene. Promoters contain specific DNA sequences such as response elements that provide a secure initial binding site for RNA polymerase and for proteins called transcription factors that recruit RNA polymerase. These transcription factors have specific activator or repressor sequences of corresponding nucleotides that attach to specific promoters and regulate gene expression. In bacteria The promoter is recognized by RNA polymerase and an associated sigma factor, which in turn are often brought to the promoter DNA by an activator protein's binding to its own DNA binding site nearby. In eukaryotes The process is more complicated, and at least seven different factors are necessary for the binding of an RNA polymerase II to the promoter. Promoters represent critical elements that can work in concert with other regulatory regions (enhancers, silencers, boundary elements/insulators) to direct the level of transcription of a given gene. A promoter is induced in response to changes in abundance or conformation of regulatory proteins in a cell, which enable activating transcription factors to recruit RNA polymerase. Identification of relative location As promoters are typically immediately adjacent to the gene in question, positions in the promoter are designated relative to the transcriptional start site, where transcription of DNA begins for a particular gene (i.e., positions upstream are negative numbers counting back from -1, for example -100 is a position 100 base pairs upstream). Relative location in the cell nucleus In the cell nucleus, it seems that promoters are distributed preferentially at the edge of the chromosomal territories, likely for the co-expression of genes on different chromosomes. Furthermore, in humans, promoters show certain structural features characteristic for each chromosome. Elements Bacterial In bacteria, the promoter contains two short sequence elements approximately 10 (Pribnow Box) and 35 nucleotides upstream from the transcription start site. The sequence at -10 (the -10 element) has the consensus sequence TATAAT. The sequence at -35 (the -35 element) has the consensus sequence TTGACA. The above consensus sequences, while conserved on average, are not found intact in most promoters. On average, only 3 to 4 of the 6 base pairs in each consensus sequence are found in any given promoter. Few natural promoters have been identified to date that possess intact consensus sequences at both the -10 and -35; artificial promoters with complete conservation of the -10 and -35 elements have been found to transcribe at lower frequencies than those with a few mismatches with the consensus. The optimal spacing between the -35 and -10 sequences is 17 bp. Some promoters contain one or more upstream promoter element (UP element) subsites (consensus sequence 5'-AAAAAARNR-3' when centered in the -42 region; consensus sequence 5'-AWWWWWTTTTT-3' when centered in the -52 region; W = A or T; R = A or G; N = any base). The above promoter sequences are recognized only by RNA polymerase holoenzyme containing sigma-70. RNA polymerase holoenzymes containing other sigma factors recognize different core promoter sequences. <-- upstream downstream --> 5'-XXXXXXXPPPPPPXXXXXXPPPPPPXXXXGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGXXXX-3' -35 -10 Gene to be transcribed Probability of occurrence of each nucleotide for -10 sequence T A T A A T 77% 76% 60% 61% 56% 82% for -35 sequence T T G A C A 69% 79% 61% 56% 54% 54% Eukaryotic Eukaryotic promoters are diverse and can be difficult to characterize, however, recent studies show that they are divided in more than 10 classes. Gene promoters are typically located upstream of the gene and can have regulatory elements several kilobases away from the transcriptional start site (enhancers). In eukaryotes, the transcriptional complex can cause the DNA to bend back on itself, which allows for placement of regulatory sequences far from the actual site of transcription. Eukaryotic RNA-polymerase-II-dependent promoters can contain a TATA box (consensus sequence TATAAA), which is recognized by the general transcription factor TATA-binding protein (TBP); and a B recognition element (BRE), which is recognized by the general transcription factor TFIIB. The TATA element and BRE typically are located close to the transcriptional start site (typically within 30 to 40 base pairs). Eukaryotic promoter regulatory sequences typically bind proteins called transcription factors that are involved in the formation of the transcriptional complex. An example is the E-box (sequence CACGTG), which binds transcription factors in the basic helix-loop-helix (bHLH) family (e.g. BMAL1-Clock, cMyc). Some promoters that are targeted by multiple transcription factors might achieve a hyperactive state, leading to increased transcriptional activity. Core promoter – the minimal portion of the promoter required to properly initiate transcription Includes the transcription start site (TSS) and elements directly upstream A binding site for RNA polymerase RNA polymerase I: transcribes genes encoding 18S, 5.8S and 28S ribosomal RNAs RNA polymerase II: transcribes genes encoding messenger RNA and certain small nuclear RNAs and microRNA RNA polymerase III: transcribes genes encoding transfer RNA, 5s ribosomal RNAs and other small RNAs General transcription factor binding sites, e.g. TATA box, B recognition element. Many other elements/motifs may be present. There is no such thing as a set of "universal elements" found in every core promoter. Proximal promoter – the proximal sequence upstream of the gene that tends to contain primary regulatory elements Approximately 250 base pairs upstream of the start site Specific transcription factor binding sites Distal promoter – the distal sequence upstream of the gene that may contain additional regulatory elements, often with a weaker influence than the proximal promoter Anything further upstream (but not an enhancer or other regulatory region whose influence is positional/orientation independent) Specific transcription factor binding sites Mammalian promoters Up-regulated expression of genes in mammals is initiated when signals are transmitted to the promoters associated with the genes. Promoter DNA sequences may include different elements such as CpG islands (present in about 70% of promoters), a TATA box (present in about 24% of promoters), initiator (Inr) (present in about 49% of promoters), upstream and downstream TFIIB recognition elements (BREu and BREd) (present in about 22% of promoters), and downstream core promoter element (DPE) (present in about 12% of promoters). The presence of multiple methylated CpG sites in CpG islands of promoters causes stable silencing of genes. However, experiments by Weingarten-Gabbay et al. showed that the presence or absence of the other elements have relatively small effects on
A PSD file has a maximum height and width of 30,000 pixels, and a length limit of two gigabytes. PhotoShop from the beginning could save files in other formats, including TIF, JPEG, and GIF. These files are smaller than PSD files because they lack the editable features of a PSD file. These formats are required to use the file in publications or on the web. The discontinued program PageMaker required TIF format. FaceBook requires JPG. Photoshop files sometimes have the file extension .PSB, which stands for "Photoshop Big" (also known as "large document format"). A PSB file extends the PSD file format, increasing the maximum height and width to 300,000 pixels and the length limit to around 4 Exabytes. The dimension limit was apparently chosen arbitrarily by Adobe, not based on computer arithmetic constraints (it is not close to a power of two, as is 30,000) but for ease of software testing. PSD and PSB formats are documented. Because of Photoshop's popularity, PSD files are widely used and supported to some extent by most competing software, including GIMP and Affinity Photo. The .PSD file format can be exported to and from Adobe's other apps, such as Adobe Illustrator, Adobe Premiere Pro, and After Effects. Plugins Photoshop functionality can be extended by add-on programs called Photoshop plugins (or plug-ins). Adobe creates some plugins, such as Adobe Camera Raw, but third-party companies develop most plugins, according to Adobe's specifications. Some are free and some are commercial software. Most plugins work with only Photoshop or Photoshop-compatible hosts, but a few can also be run as standalone applications. There are various types of plugins, such as filter, export, import, selection, color correction, and automation. The most popular plugins are the filter plugins (also known as a 8bf plugins), available under the Filter menu in Photoshop. Filter plugins can either modify the current image or create content. Below are some popular types of plugins, and some well-known companies associated with them: Color correction plugins (Alien Skin Software, Nik Software, OnOne Software, Topaz Labs Software, The Plugin Site, etc.) Special effects plugins (Alien Skin Software, Auto FX Software, AV Bros., Flaming Pear Software, etc.) 3D effects plugins (Andromeda Software, Strata, etc.) Adobe Camera Raw (also known as ACR and Camera Raw) is a special plugin, supplied free by Adobe, used primarily to read and process raw image files so that the resulting images can be processed by Photoshop. It can also be used from within Adobe Bridge. Photoshop tools Upon loading Photoshop, a sidebar with a variety of tools with multiple image-editing functions appears to the left of the screen. These tools typically fall under the categories of drawing; painting; measuring and navigation; selection; typing; and retouching. Some tools contain a small triangle in the bottom right of the toolbox icon. These can be expanded to reveal similar tools. While newer versions of Photoshop are updated to include new tools and features, several recurring tools that exist in most versions are discussed below. In some newer versions hovering along the tools gives a small Video glimpse of the tool. Pen tool Photoshop includes a few versions of the pen tool. The pen tool creates precise paths that can be manipulated using anchor points. The free form pen tool allows the user to draw paths freehand, and with the magnetic pen tool, the drawn path attaches closely to outlines of objects in an image, which is useful for isolating them from a background. Clone stamp tool The Clone Stamp tool duplicates one part of an image to another part of the same image by way of a brush. The duplication is either in full or in part depending on the mode. The user can also clone part of one layer to another layer. The Clone Stamp tool is useful for duplicating objects or removing a defect in an image. Shape tools Photoshop provides an array of shape tools including rectangles, rounded rectangles, ellipses, polygons and lines. These shapes can be manipulated by the pen tool, direct selection tool etc. to make vector graphics. In addition, Photoshop provides its own shapes like animals, signs and plants. Measuring and navigation The eyedropper tool selects a color from an area of the image that is clicked, and samples it for future use. The hand tool navigates an image by moving it in any direction, and the zoom tool enlarges the part of an image that is clicked on, allowing for a closer view. Selection tools Selection tools are used to select all or any part of a picture to perform cut, copy, edit, or retouching operations. Cropping The crop tool can be used to select a particular area of an image and discard the portions outside the chosen section. This tool assists in creating a focus point on an image and unnecessary or excess space. Cropping allows enhancement of a photo's composition while decreasing the file size. The crop tool is in the tools palette, which is located on the right side of the document. By placing the cursor over the image, the user can drag the cursor to the desired area. Once the Enter key is pressed, the area outside the rectangle will be cropped. The area outside the rectangle is the discarded data, which allows for the file size to be decreased. The crop tool can alternatively be used to extend the canvas size by clicking and dragging outside the existing image borders. Slicing The slice and slice select tools, like the crop tool, are used in isolating parts of images. The slice tool can be used to divide an image into different sections, and these separate parts can be used as pieces of a web page design once HTML and CSS are applied. The slice select tool allows sliced sections of an image to be adjusted and shifted. Moving The move tool can be used to drag the entirety of a single layer or more if they are selected. Alternatively, once an area of an image is highlighted, the move tool can be used to manually relocate the selected piece to anywhere on the canvas. Marquee The marquee is a tool that can make selections that are a single row, single column, rectangular and elliptical. An area that has been selected can be edited without affecting the rest of the image. This tool can also crop an image; it allows for better control. In contrast to the crop tool, the marquee tool allows for more adjustments to the selected area before cropping. The only marquee tool that does not allow cropping is the elliptical. Although the single row and column marquee tools allow for cropping, they are not ideal, because they only crop a line. The rectangular marquee tool is the preferred option. Once the tool has been selected, dragging the tool across the desired area will select it. The selected area will be outlined by dotted lines, referred to as "marching ants". To set a specific size or ratio, the tool options bar provides these settings. Before selecting an area, the desired size or ratio must be set by adjusting the width and height. Any changes such as color, filters, location, etc. should be made before cropping. To crop the selection, the user must go to the image tab and select crop. Lasso The lasso tool is similar to the marquee tool, however, the user can make a custom selection by drawing it freehand. There are three options for the lasso tool – regular, polygonal, and magnetic. The regular lasso tool allows the user to have drawing capabilities. Photoshop will complete the selection once the mouse button is released. The user may also complete the selection by connecting the end point to the starting point. The "marching ants" will indicate if a selection has been made. The polygonal lasso tool will draw only straight lines, which makes it an ideal choice for images with many straight lines. Unlike the regular lasso tool, the user must continually click around the image to outline the shape. To complete the selection, the user must connect the end point to the starting point just like the regular lasso tool. Magnetic lasso tool are considered the smart tool. It can do the same as the other two, but it can also detect the edges of an image once the user selects a starting point. It detects by examining the color pixels as the cursor moves over the desired area. Closing the selection is the same as the other two, which should also should display the "marching ants" once the selection has been closed. The quick selection tool selects areas based on edges, similarly to the magnetic lasso tool. The difference between this tool and the lasso tool is that there is no starting and ending point. For this reason, the selected area can be added onto as much as possible without starting over. By dragging the cursor over the desired area, the quick selection tool detects the edges of the image. The "marching ants" allow the user to know what is currently being selected. Once the user is done, the selected area can be edited without affecting the rest of the image. One of the features that makes this tool especially user friendly is that the SHIFT key is not needed to add more to the selection; by default, extra mouse clicks will be added to the selection rather than creating a new selection. Magic wand The magic wand tool selects areas based on pixels of similar values. One click will select all neighboring pixels of similar value within a tolerance level set by the user. If the eyedropper tool is selected in the options bar, then the magic wand can determine the value needed to evaluate the pixels; this is based on the sample size setting in the eyedropper tool. This tool is inferior to the quick selection tool which works much the same but with much better results and more intuitive controls. The user must decide what settings to use or if the image is right for this tool. Eraser The Eraser tool erases content based on the active layer. If the user is on the text layer, then any text across which the tool is dragged will be erased. The eraser will convert the pixels to transparent, unless the background layer is selected. The size and style of the eraser can be selected in the options bar. This tool is unique in that it can take the form of the paintbrush and pencil tools. In addition to the straight eraser tool, there are two more available options – background eraser and magic eraser. The background eraser deletes any part of the image that is on the edge of an object. This tool is often used to extract objects from the background. The magic eraser tool deletes based on similar colored pixels. It is very similar to the magic wand tool. This tool is ideal for deleting areas with the same color or tone that contrasts with the rest of the image. Video editing In Adobe CS5 Extended	renamed the program ImagePro, but the name was already taken. Later that year, Thomas renamed his program Photoshop and worked out a short-term deal with scanner manufacturer Barneyscan to distribute copies of the program with a slide scanner; a "total of about 200 copies of Photoshop were shipped" this way. During this time, John traveled to Silicon Valley and gave a demonstration of the program to engineers at Apple and Russell Brown, art director at Adobe. Both showings were successful, and Adobe decided to purchase the license to distribute in September 1988. While John worked on plug-ins in California, Thomas remained in Ann Arbor writing code. Photoshop 1.0 was released on February 19, 1990, for Macintosh exclusively. The Barneyscan version included advanced color editing features that were stripped from the first Adobe shipped version. The handling of color slowly improved with each release from Adobe and Photoshop quickly became the industry standard in digital color editing. At the time Photoshop 1.0 was released, digital retouching on dedicated high-end systems (such as the Scitex) cost around $300 an hour for basic photo retouching. The list price of Photoshop 1.0 for Macintosh in 1990 was $895. Photoshop was initially only available on Macintosh. In 1993, Adobe chief architect Seetharaman Narayanan ported Photoshop to Microsoft Windows. The Windows port led to Photoshop reaching a wider mass market audience as Microsoft's global reach expanded within the next few years. On March 31, 1995, Adobe purchased the rights for Photoshop from Thomas and John Knoll for $34.5 million so Adobe would no longer need to pay a royalty for each copy sold. File format Photoshop files have default file extension as .PSD, which stands for "Photoshop Document". A PSD file stores an image with support for all features of Photoshop; these include layers with masks, transparency, text, alpha channels and spot colors, clipping paths, and duotone settings. This is in contrast to many other file formats (e.g., .JPG or .GIF) that restrict content to provide streamlined, predictable functionality. A PSD file has a maximum height and width of 30,000 pixels, and a length limit of two gigabytes. PhotoShop from the beginning could save files in other formats, including TIF, JPEG, and GIF. These files are smaller than PSD files because they lack the editable features of a PSD file. These formats are required to use the file in publications or on the web. The discontinued program PageMaker required TIF format. FaceBook requires JPG. Photoshop files sometimes have the file extension .PSB, which stands for "Photoshop Big" (also known as "large document format"). A PSB file extends the PSD file format, increasing the maximum height and width to 300,000 pixels and the length limit to around 4 Exabytes. The dimension limit was apparently chosen arbitrarily by Adobe, not based on computer arithmetic constraints (it is not close to a power of two, as is 30,000) but for ease of software testing. PSD and PSB formats are documented. Because of Photoshop's popularity, PSD files are widely used and supported to some extent by most competing software, including GIMP and Affinity Photo. The .PSD file format can be exported to and from Adobe's other apps, such as Adobe Illustrator, Adobe Premiere Pro, and After Effects. Plugins Photoshop functionality can be extended by add-on programs called Photoshop plugins (or plug-ins). Adobe creates some plugins, such as Adobe Camera Raw, but third-party companies develop most plugins, according to Adobe's specifications. Some are free and some are commercial software. Most plugins work with only Photoshop or Photoshop-compatible hosts, but a few can also be run as standalone applications. There are various types of plugins, such as filter, export, import, selection, color correction, and automation. The most popular plugins are the filter plugins (also known as a 8bf plugins), available under the Filter menu in Photoshop. Filter plugins can either modify the current image or create content. Below are some popular types of plugins, and some well-known companies associated with them: Color correction plugins (Alien Skin Software, Nik Software, OnOne Software, Topaz Labs Software, The Plugin Site, etc.) Special effects plugins (Alien Skin Software, Auto FX Software, AV Bros., Flaming Pear Software, etc.) 3D effects plugins (Andromeda Software, Strata, etc.) Adobe Camera Raw (also known as ACR and Camera Raw) is a special plugin, supplied free by Adobe, used primarily to read and process raw image files so that the resulting images can be processed by Photoshop. It can also be used from within Adobe Bridge. Photoshop tools Upon loading Photoshop, a sidebar with a variety of tools with multiple image-editing functions appears to the left of the screen. These tools typically fall under the categories of drawing; painting; measuring and navigation; selection; typing; and retouching. Some tools contain a small triangle in the bottom right of the toolbox icon. These can be expanded to reveal similar tools. While newer versions of Photoshop are updated to include new tools and features, several recurring tools that exist in most versions are discussed below. In some newer versions hovering along the tools gives a small Video glimpse of the tool. Pen tool Photoshop includes a few versions of the pen tool. The pen tool creates precise paths that can be manipulated using anchor points. The free form pen tool allows the user to draw paths freehand, and with the magnetic pen tool, the drawn path attaches closely to outlines of objects in an image, which is useful for isolating them from a background. Clone stamp tool The Clone Stamp tool duplicates one part of an image to another part of the same image by way of a brush. The duplication is either in full or in part depending on the mode. The user can also clone part of one layer to another layer. The Clone Stamp tool is useful for duplicating objects or removing a defect in an image. Shape tools Photoshop provides an array of shape tools including rectangles, rounded rectangles, ellipses, polygons and lines. These shapes can be manipulated by the pen tool, direct selection tool etc. to make vector graphics. In addition, Photoshop provides its own shapes like animals, signs and plants. Measuring and navigation The eyedropper tool selects a color from an area of the image that is clicked, and samples it for future use. The hand tool navigates an image by moving it in any direction, and the zoom tool enlarges the part of an image that is clicked on, allowing for a closer view. Selection tools Selection tools are used to select all or any part of a picture to perform cut, copy, edit, or retouching operations. Cropping The crop tool can be used to select a particular area of an image and discard the portions outside the chosen section. This tool assists in creating a focus point on an image and unnecessary or excess space. Cropping allows enhancement of a photo's composition while decreasing the file size. The crop tool is in the tools palette, which is located on the right side of the document. By placing the cursor over the image, the user can drag the cursor to the desired area. Once the Enter key is pressed, the area outside the rectangle will be cropped. The area outside the rectangle is the discarded data, which allows for the file size to be decreased. The crop tool can alternatively be used to extend the canvas size by clicking and dragging outside the existing image borders. Slicing The slice and slice select tools, like the crop tool, are used in isolating parts of images. The slice tool can be used to divide an image into different sections, and these separate parts can be used as pieces of a web page design once HTML and CSS are applied. The slice select tool allows sliced sections of an image to be adjusted and shifted. Moving The move tool can be used to drag the entirety of a single layer or more if they are selected. Alternatively, once an area of an image is highlighted, the move tool can be used to manually relocate the selected piece to anywhere on the canvas. Marquee The marquee is a tool that can make selections that are a single row, single column, rectangular and elliptical. An area that has been selected can be edited without affecting the rest of the image. This tool can also crop an image; it allows for better control. In contrast to the crop tool, the marquee tool allows for more adjustments to the selected area before cropping. The only marquee tool that does not allow cropping is the elliptical. Although the single row and column marquee tools allow for cropping, they are not ideal, because they only crop a line. The rectangular marquee tool is the preferred option. Once the tool has been selected, dragging the tool across the desired area will select it. The selected area will be outlined by dotted lines, referred to as "marching ants". To set a specific size or ratio, the tool options bar provides these settings. Before selecting an area, the desired size or ratio must be set by adjusting the width and height. Any changes such as color, filters, location, etc. should be made before cropping. To crop the selection, the user must go to the image tab and select crop. Lasso The lasso tool is similar to the marquee tool, however, the user can make a custom selection by drawing it freehand. There are three options for the lasso tool – regular, polygonal, and magnetic. The regular lasso tool allows the user to have drawing capabilities. Photoshop will complete the selection once the mouse button is released. The user may also complete the selection by connecting the end point to the starting point. The "marching ants" will indicate if a selection has been made. The polygonal lasso tool will draw only straight lines, which makes it an ideal choice for images with many straight lines. Unlike the regular lasso tool, the user must continually click around the image to outline the shape. To complete the selection, the user must connect the end point to the starting point just like the regular lasso tool. Magnetic lasso tool are considered the smart tool. It can do the same as the other two, but it can also detect the edges of an image once the user selects a starting point. It detects by examining the color pixels as the cursor moves over the desired area. Closing the selection is the same as the other two, which should also should display the "marching ants" once the selection has been closed. The quick selection tool selects areas based on edges, similarly to the magnetic lasso tool. The difference between this tool and the lasso tool is that there is no starting and ending point. For this reason, the selected area can be added onto as much as possible without starting over. By dragging the cursor over the desired area, the quick selection tool detects the edges of the image. The "marching ants" allow the user to know what is currently being selected. Once the user is done, the selected area can be edited without affecting the rest of the image. One of the features that makes this tool especially user friendly is that the SHIFT key is not needed to add more to the selection; by default, extra mouse clicks will be added to the selection rather than creating a new selection. Magic wand The magic wand tool selects areas based on pixels of similar values. One click will select all neighboring pixels of similar value within a tolerance level set by the user. If the eyedropper tool is selected in the options bar, then the magic wand can determine the value needed to evaluate the pixels; this is based on the sample size setting in the eyedropper tool. This tool is inferior to the quick selection tool which works much the same but with much better results and more intuitive controls. The user must decide what settings to use or if the image is right for this tool. Eraser The Eraser tool erases content based on the active layer. If the user is on the text layer, then any text across which the tool is dragged will be erased. The eraser will convert the pixels to transparent, unless the background layer is selected. The size and style of the eraser can be selected in the options bar. This tool is unique in that it can take the form of the paintbrush and pencil tools. In addition to the straight eraser tool, there are two more available options – background eraser and magic eraser. The background eraser deletes any part of the image that is on the edge of an object. This tool is often used to extract objects from the background. The magic eraser tool deletes based on similar colored pixels. It is very similar to the magic wand tool. This tool is ideal for deleting areas with the same color or tone that contrasts with the rest of the image. Video editing In Adobe CS5 Extended edition, video editing is comprehensive and efficient with a broad compatibility of video file formats such as MOV, AVI and MPEG-4 formats and easy workflow. Using simple combinations of keys video layers can easily be modified, with other features such as adding text and creating animations using single images. 3D extrusion With the Extended version of Photoshop CS5, 2D elements of an artwork can easily become three-dimensional with the click of a button. Extrusions of texts, an available library of materials for three-dimensional, and even wrapping two-dimensional images around 3D geometry. Mobile integration Third-party plugins have also been added to the most recent version of Photoshop where technologies such as the iPad have integrated the software with different types of applications. Applications like the Adobe Eazel painting app allows the user to easily create paintings with their fingertips and use an array of different paint from dry to wet in order to create rich color blending. In October 2018, it was announced that the full Photoshop engine will be released for iPad next year. The program will feature cloud syncing with other devices and a simpler interface than the desktop version. Camera raw With the Camera Raw plug-in, raw images can be processed without the use of Adobe Photoshop Lightroom, along with other image file formats such as JPEG, TIFF, or PNG. The plug-in allows users to remove noise without the side-effect of over-sharpening, add grain, and even perform post-crop vignetting. 3D printing tools From version 14.1, users can create and edit designs for 3D printing. Artists can add color, adjust the shape or rotate the angles of imported models, or design original 3D models from scratch. Color replacement tool The Color Replacement Tool allows the user to change the color, while maintaining the highlights and shadows of the original image, of pieces of the image. By selecting Brushes and right clicking, the Color Replacement Tool is the third option down. What is important to note with this tool is the foreground color. The foreground color is what will be applied when painting along the chosen part of the image with the Color Replacement tool. Cultural impact Photoshop and derivatives such as Photoshopped (or just Shopped) have become verbs that are sometimes used to refer to images edited by Photoshop, or any image manipulation program. The same happens not only in English but as the Portuguese Wikipedia entry for image manipulation attests, even in that language, with the trademark being followed by the Portuguese verb termination -ar, yielding the word "photoshopar" (to photoshop). Such derivatives are discouraged by Adobe because, in order to maintain validity and protect the trademark from becoming generic, trademarks must be used as proper nouns. Version history Older versions Photoshop's naming scheme was initially based on version numbers, from version 0.07 (codename "Bond"; double-oh-seven), through version 0.87 (codename "Seurat" which was the first commercial version, sold as "Barneyscan XP"), version 1.0 (February 1990) all the way to version 7.0.1. Adobe published 7 major and many minor versions before the October 2003 introduction of version 8.0 which brought with it the Creative Suite branding. Notable milestone features would be: Filters, Colour Separation, Virtual Memory (1.0), Paths, CMYK color (2.0), 16-bits-per-channel support, availability on Microsoft Windows (2.5), Layers, tabbed Palettes (3.0), Adjustments, Actions, Freeform Transform, PNG support (4.0), Editable Type, Magnetic Lasso and Pen, Freeform Pen, Multiple Undo, Layer Effects (5.0), Save For Web (5.5), Vector Shapes, revised User Interface (6.0), Vector Text, Healing Brush, Spell Check (7.0), Camera RAW (7.0.1). In February 2013 Adobe donated the source code of the 1990 1.0.1 version of Photoshop to the Computer History Museum. CS (version 8) The first Photoshop CS was commercially released in October 2003 as the eighth major version of Photoshop. Photoshop CS increased user control with a reworked file browser augmenting search versatility, sorting and sharing capabilities and the Histogram Palette which monitors changes in the image as they are made to the document. Match Color was also introduced in CS, which reads color data to achieve a uniform expression throughout a series of pictures. CS2 (version 9) Photoshop CS2, released in May 2005, expanded on its predecessor with a new set of tools and features. It included an upgraded Spot Healing Brush, which is mainly used for handling common photographic problems such as blemishes, red-eye, noise, blurring and lens distortion. One of the most significant inclusions in CS2 was the implementation of Smart Objects, which allows users to scale and transform images and vector illustrations without losing image quality, as well as create linked duplicates of embedded graphics so that a single edit updates across multiple iterations. Adobe responded to feedback from the professional media industry by implementing non-destructive editing as well as the producing and modifying of 32-Bit High Dynamic Range (HDR) images, which are optimal for 3D rendering and advanced compositing. FireWire Previews could also be viewed on a monitor via a direct export feature. Photoshop CS2 brought the Vanishing Point and Image Warping tools. Vanishing Point makes tedious graphic and photo retouching endeavors much simpler by letting users clone, paint and transform image objects while maintaining visual perspective. Image Warping makes it easy to digitally distort an image into a shape by choosing on-demand presets or by dragging control points. The File Browser was upgraded to Adobe Bridge, which functioned as a hub for productivity, imagery and creativity, providing multi-view file browsing and smooth cross-product integration across Adobe Creative Suite 2 software. Adobe Bridge also provided access to Adobe Stock Photos, a new stock photography service that offered users one-stop shopping across five elite stock image providers to deliver high-quality, royalty-free images for layout and design. Camera Raw version 3.0 was a new addition in CS2, and it allowed settings for multiple raw files to be modified simultaneously. In addition, processing multiple raw files to other formats including JPEG, TIFF, DNG or PSD, could be done in the background without executing
Pro X6 Ultimate includes Athentech Imaging's Perfectly Clear and Reallusion's FaceFilter3 Standard. PaintShop Pro X7 Ultimate includes those same two items. The bundled extras cannot be installed unless that version of the PaintShop program is already installed. However, once a bundled extra such as a plugin has been installed, the installed files can be copied to other versions, e.g., a plugin installed under X5 can be copied to X6 and even if X5 is then uninstalled, the plugin will continue to work under X6. Corel releases a new X version roughly annually, so this ability to copy means PSP users do not have to choose between updating or continued use of Ultimate add-ons from previous versions. Other related versions and products Paint Shop Pro Personal is a version of JASC Paint Shop Pro 9 for the Japanese market, published by Sourcenext Corporation. Paint Shop Photo Album is a simplified version of Paint Shop Pro designed to enhance, organize, and share digital photos. The Corel version was released as version 5. Corel Paint Shop Pro Album Personal is a version of Corel Paint Shop Pro Album 5 Deluxe for Japanese market, published by Sourcenext Corporation. Corel Photo Album is the successor of Jasc Paint Shop Photo Album. First release was version 6. Corel PaintShop Photo Express is the successor of Corel Photo Album. First release was PaintShop Photo Express 2010. Paint Shop Pro Photo Studio is a site launched as part of Corel Paint Shop Pro Photo X2	to X3), PaintShop Pro was marketed as "Corel Paint Shop Pro Photo". Having dropped the "Photo" part of the name in version X4, Paintshop Pro X5 was derived from Ulead Photo Explorer after Corel's acquisition of Ulead. On November 28, 2007, Corel announced that the office in Eden Prairie, Minnesota, where Paint Shop Pro was created, would be shut down, with development moving to offices in California and China. Version history JASC Paint Shop releases: 1990?–1993 In the table below, italicized dates are approximate, based on the earliest file timestamp on JASC or Corel's FTP server. Non-italicized dates are sourced from official press releases or notifications posted on JASC's web site. JASC Paint Shop Pro releases: 1990–2004 Corel Paint Shop Pro releases: 2005 Corel Paint Shop Pro Photo releases: 2006–2008 Corel PaintShop Photo Pro releases: 2010-2011 Corel PaintShop Pro releases: 2011–present Picture tubes Picture tubes are graphic images with no background. They are often used as a starting point for complex images; that is, they are combined with other image elements to produce a final work. Tubes can also be regarded as graphic brushes based on a pre-created image; this was their original use. Instead of leaving a trace of color on the canvas, they would leave a trail of images. Popular tube subjects include alphabets, humans (also known as dollz), animal and toy figures, flowers, love messages and seasonal symbols. The tube system originated with PSP Pro version 5. Native tube files may be in .tub, .psp, .pspimage, and .psptube formats. XnView, IrfanView, and TubeEx are separate graphics programs that can convert tube files (.tub) to .png. Ultimate edition PaintShop Pro Photo X2 Ultimate was released towards the end of life of PaintShop Pro Photo X2, in September 2008. It included 150 additional picture frames and Picture Tubes, the programs Background Remover, Corel Painter Photo Essentials 4, and Photorecovery, as well as RAW support for 250 cameras and a 2GB flash drive. Subsequent Ultimate editions were released contemporaneously with the basic version. PaintShop Pro X4 Ultimate included Nik Color Efex Pro 3.0, a voucher for 21 images from Fotolia at high quality, and additional Picture Tubes. X5 Ultimate included Reallusion FaceFilter Studio 2.0, NIK Color Efex Pro 3.0, and "over 100 unique brushes, textures and royalty-free backgrounds". PaintShop Pro X6 Ultimate includes Athentech Imaging's Perfectly Clear and Reallusion's FaceFilter3 Standard. PaintShop Pro X7 Ultimate includes those same two items. The bundled extras cannot be installed unless that version of the PaintShop program is already installed. However, once a bundled extra such as a plugin has
and Carlsmith's 1959 experiment in which participants were asked to complete a very dull task for an hour. Some were paid $20, while others were paid $1, and afterwards they were instructed to tell the next waiting participants that the experiment was fun and exciting. Those who were paid $1 were much more likely to convince the next participants that the experiment really was enjoyable than those who received $20. This is because $20 is enough reason to participate in a dull task for an hour, so there is no dissonance. Those who received $1 experienced great dissonance, so they had to truly convince themselves that the task actually was enjoyable to avoid feeling taken advantage of, and therefore reduce their dissonance. Elaboration likelihood model Persuasion has traditionally been associated with two routes. Central route: Whereby an individual evaluates information presented to them based on the pros and cons of it and how well it supports their values Peripheral route: Change is mediated by how attractive the source of communication is and by bypassing the deliberation process. The Elaboration likelihood model (ELM) forms a new facet of the route theory. It holds that the probability of effective persuasion depends on how successful the communication is at bringing to mind a relevant mental representation, which is the elaboration likelihood. Thus if the target of the communication is personally relevant, this increases the elaboration likelihood of the intended outcome and would be more persuasive if it were through the central route. Communication which does not require careful thought would be better suited to the peripheral route. Functional theories Functional theorists attempt to understand the divergent attitudes individuals have towards people, objects or issues in different situations. There are four main functional attitudes: Adjustment function: A main motivation for individuals is to increase positive external rewards and minimize the costs. Attitudes serve to direct behavior towards the rewards and away from punishment. Ego Defensive function: The process by which an individual protects their ego from being threatened by their own negative impulses or threatening thoughts. Value-expressive: When an individual derives pleasure from presenting an image of themselves which is in line with their self-concept and the beliefs that they want to be associated with. Knowledge function: The need to attain a sense of understanding and control over one's life. An individual's attitudes therefore serve to help set standards and rules which govern their sense of being. When communication targets an underlying function, its degree of persuasiveness influences whether individuals change their attitude after determining that another attitude would more effectively fulfill that function. Inoculation theory A vaccine introduces a weak form of a virus that can easily be defeated to prepare the immune system should it need to fight off a stronger form of the same virus. In much the same way, the theory of inoculation suggests that a certain party can introduce a weak form of an argument that is easily thwarted in order to make the audience inclined to disregard a stronger, full-fledged form of that argument from an opposing party. This often occurs in negative advertisements and comparative advertisements—both for products and political causes. An example would be a manufacturer of a product displaying an ad that refutes one particular claim made about a rival's product, so that when the audience sees an ad for said rival product, they refute the product claims automatically. Narrative transportation theory Narrative transportation theory proposes that when people lose themselves in a story, their attitudes and intentions change to reflect that story. The mental state of narrative transportation can explain the persuasive effect of stories on people, who may experience narrative transportation when certain contextual and personal preconditions are met, as Green and Brock postulate for the transportation-imagery model. Narrative transportation occurs whenever the story receiver experiences a feeling of entering a world evoked by the narrative because of empathy for the story characters and imagination of the story plot. Social judgment theory Social judgment theory suggests that when people are presented with an idea or any kind of persuasive proposal, their natural reaction is to immediately seek a way to sort the information subconsciously and react to it. We evaluate the information and compare it with the attitude we already have, which is called the initial attitude or anchor point. When trying to sort incoming persuasive information, an audience evaluates whether it lands in their latitude of acceptance, latitude of non-commitment or indifference, or the latitude of rejection. The size of these latitudes varies from topic to topic. Our "ego-involvement" generally plays one of the largest roles in determining the size of these latitudes. When a topic is closely connected to how we define and perceive ourselves, or deals with anything we care passionately about, our latitudes of acceptance and non-commitment are likely to be much smaller and our attitude of rejection much larger. A person's anchor point is considered to be the center of his latitude of acceptance, the position that is most acceptable to him. An audience is likely to distort incoming information to fit into their unique latitudes. If something falls within the latitude of acceptance, the subject tends to assimilate the information and consider it closer to his anchor point than it really is. Inversely, if something falls within the latitude of rejection, the subject tends to contrast the information and convince himself the information is farther away from his anchor point than it really is. When trying to persuade an individual target or an entire audience, it is vital to first learn the average latitudes of acceptance, non-commitment, and rejection of your audience. It is ideal to use persuasive information that lands near the boundary of the latitude of acceptance if the goal is to change the audience's anchor point. Repeatedly suggesting ideas on the fringe of the acceptance latitude makes people gradually adjust their anchor points, while suggesting ideas in the rejection latitude or even the non-commitment latitude does not change the audience's anchor point. Methods Persuasion methods are also sometimes referred to as persuasion tactics or persuasion strategies. Use of force There is the use of force in persuasion, which does not have any scientific theories, except for its use to make demands. The use of force is then a precedent to the failure of less direct means of persuasion. Application of this strategy can be interpreted as a threat since the persuader does not give options to his or her request. Weapons of influence Robert Cialdini, in Influence, his book on persuasion, defined six "influence cues or weapons of influence": Influence is the process of changing. Reciprocity The principle of reciprocity states that when a person provides us with something, we attempt to repay him or her in kind. Reciprocation produces a sense of obligation, which can be a powerful tool in persuasion. The reciprocity rule is effective because it can be overpowering and instill in us a sense of obligation. Generally, we have a dislike for individuals who neglect to return a favor or provide payment when offered a free service or gift. As a result, reciprocation is a widely	performance (planning?), self-talk, focus on past success, comparison of outcomes via persuasive argument, pros/cons and comparative imaging of future outcomes, identification of self as role model, self-affirmation, reframing, cognitive dissonance, reattribution, (increasing salience of) antecedents A typical instantiations of these techniques in therapy isexposure / response prevention for OCD. Conditioning theories Conditioning plays a huge part in the concept of persuasion. It is more often about leading someone into taking certain actions of their own, rather than giving direct commands. In advertisements for example, this is done by attempting to connect a positive emotion to a brand/product logo. This is often done by creating commercials that make people laugh, using a sexual undertone, inserting uplifting images and/or music etc. and then ending the commercial with a brand/product logo. Great examples of this are professional athletes. They are paid to connect themselves to things that can be directly related to their roles; sport shoes, tennis rackets, golf balls, or completely irrelevant things like soft drinks, popcorn poppers and panty hose. The important thing for the advertiser is to establish a connection to the consumer. This conditioning is thought to affect how people view certain products, knowing that most purchases are made on the basis of emotion. Just like you sometimes recall a memory from a certain smell or sound, the objective of some ads is solely to bring back certain emotions when you see their logo in your local store. The hope is that repeating the message several times makes consumers more likely to purchase the product because they already connect it with a good emotion and positive experience. Stefano DellaVigna and Matthew Gentzkow did a comprehensive study on the effects of persuasion in different domains. They discovered that persuasion has little or no effect on advertisement; however, there was a substantial effect of persuasion on voting if there was face-to-face contact. Cognitive dissonance theory Leon Festinger originally proposed the theory of cognitive dissonance in 1957. He theorized that human beings constantly strive for mental consistency. Our cognition (thoughts, beliefs, or attitudes) can be in agreement, unrelated, or in disagreement with each other. Our cognition can also be in agreement or disagreement with our behaviors. When we detect conflicting cognition, or dissonance, it gives us a sense of incompleteness and discomfort. For example, a person who is addicted to smoking cigarettes but also suspects it could be detrimental to his health suffers from cognitive dissonance. Festinger suggests that we are motivated to reduce this dissonance until our cognition is in harmony with itself. We strive for mental consistency. There are four main ways we go about reducing or eliminating our dissonance: changing our minds about one of the facets of cognition reducing the importance of a cognition increasing the overlap between the two, and re-evaluating the cost/reward ratio. Revisiting the example of the smoker, he can either quit smoking, reduce the importance of his health, convince himself he is not at risk, or that the reward of smoking is worth the cost of his health. Cognitive dissonance is powerful when it relates to competition and self-concept. The most famous example of how cognitive dissonance can be used for persuasion comes from Festinger and Carlsmith's 1959 experiment in which participants were asked to complete a very dull task for an hour. Some were paid $20, while others were paid $1, and afterwards they were instructed to tell the next waiting participants that the experiment was fun and exciting. Those who were paid $1 were much more likely to convince the next participants that the experiment really was enjoyable than those who received $20. This is because $20 is enough reason to participate in a dull task for an hour, so there is no dissonance. Those who received $1 experienced great dissonance, so they had to truly convince themselves that the task actually was enjoyable to avoid feeling taken advantage of, and therefore reduce their dissonance. Elaboration likelihood model Persuasion has traditionally been associated with two routes. Central route: Whereby an individual evaluates information presented to them based on the pros and cons of it and how well it supports their values Peripheral route: Change is mediated by how attractive the source of communication is and by bypassing the deliberation process. The Elaboration likelihood model (ELM) forms a new facet of the route theory. It holds that the probability of effective persuasion depends on how successful the communication is at bringing to mind a relevant mental representation, which is the elaboration likelihood. Thus if the target of the communication is personally relevant, this increases the elaboration likelihood of the intended outcome and would be more persuasive if it were through the central route. Communication which does not require careful thought would be better suited to the peripheral route. Functional theories Functional theorists attempt to understand the divergent attitudes individuals have towards people, objects or issues in different situations. There are four main functional attitudes: Adjustment function: A main motivation for individuals is to increase positive external rewards and minimize the costs. Attitudes serve to direct behavior towards the rewards and away from punishment. Ego Defensive function: The process by which an individual protects their ego from being threatened by their own negative impulses or threatening thoughts. Value-expressive: When an individual derives pleasure from presenting an image of themselves which is in line with their self-concept and the beliefs that they want to be associated with. Knowledge function: The need to attain a sense of understanding and control over one's life. An individual's attitudes therefore serve to help set standards and rules which govern their sense of being. When communication targets an underlying function, its degree of persuasiveness influences whether individuals change their attitude after determining that another attitude would more effectively fulfill that function. Inoculation theory A vaccine introduces a weak form of a virus that can easily be defeated to prepare the immune system should it need to fight off a stronger form of the same virus. In much the same way, the theory of inoculation suggests that a certain party can introduce a weak form of an argument that is easily thwarted in order to make the audience inclined to disregard a stronger, full-fledged form of that argument from an opposing party. This often occurs in negative advertisements and comparative advertisements—both for products and political causes. An example would be a manufacturer of a product displaying an ad that refutes one particular claim made about a rival's product, so that when the audience sees an ad for said rival product, they refute the product claims automatically. Narrative transportation theory Narrative transportation theory proposes that when people lose themselves in a story, their attitudes and intentions change to reflect that story. The mental state of narrative transportation can explain the persuasive effect of stories on people, who may experience narrative transportation when certain contextual and personal preconditions are met, as Green and Brock postulate for the transportation-imagery model. Narrative transportation occurs whenever the story receiver experiences a feeling of entering a world evoked by the narrative because of empathy for the story characters and imagination of the story plot. Social judgment theory Social judgment theory suggests that when people are presented with an idea or any kind of persuasive proposal, their natural reaction is to immediately seek a way to sort the information subconsciously and react to it. We evaluate the information and compare it with the attitude we already have, which is called the initial attitude or anchor point. When trying to sort incoming persuasive information, an audience evaluates whether it lands in their latitude of acceptance, latitude of non-commitment or indifference, or the latitude of rejection. The size of these latitudes varies from topic to topic. Our "ego-involvement" generally plays one of the largest roles in determining the size of these latitudes. When a topic is closely connected to how we define and perceive ourselves, or deals with anything we care passionately about, our latitudes of acceptance and non-commitment are likely to be much smaller and our attitude of rejection much larger. A person's anchor point is considered to be the center of his latitude of acceptance, the position that is most acceptable to him. An audience is likely to distort incoming information to fit into their unique latitudes. If something falls within the latitude of acceptance, the subject tends to assimilate the information and consider it closer to his anchor point than it really is. Inversely, if something falls within the latitude of rejection, the subject tends to contrast the information and convince himself the information is farther away from his anchor point than it really is. When trying to persuade an individual target or an entire audience, it is vital to first learn the average latitudes of acceptance, non-commitment, and rejection of your audience. It is ideal to use persuasive information that lands near the boundary of the latitude of acceptance if the goal is to change the audience's anchor point. Repeatedly suggesting ideas on the fringe of the acceptance latitude makes people gradually adjust their anchor points, while suggesting ideas in the rejection latitude or even the non-commitment latitude does not change the audience's anchor point. Methods Persuasion methods are also sometimes referred to as persuasion tactics or persuasion strategies. Use of force There is the use of force in persuasion, which does not have any scientific theories, except for its use to make demands. The use of force is then a precedent to the failure of less direct means of persuasion. Application of this strategy can be interpreted as a threat since the persuader does not give options to his or her request. Weapons of influence Robert Cialdini, in Influence, his book on persuasion, defined six "influence cues or weapons of influence": Influence is the process of changing. Reciprocity The principle of reciprocity states that when a person provides us with something, we attempt to repay him or her in kind. Reciprocation produces a sense of obligation, which can be a powerful tool in persuasion. The reciprocity rule is effective because it can be overpowering and instill in us a sense of obligation. Generally, we have a dislike for individuals who neglect to return a favor or provide payment when offered a free service or gift. As a result, reciprocation is a widely held principle. This societal standard makes reciprocity extremely powerful persuasive technique, as it can result in unequal exchanges and can even apply to an uninvited first favor. Reciprocity applies to the marketing field because of its use as a powerful persuasive technique. The marketing tactic of "free samples" demonstrates the reciprocity rule because of the sense of obligation that the rule produces. This sense of obligation comes from the desire to repay the marketer for the gift of a "free sample." Commitment and consistency Consistency is an important aspect of persuasion because it: is highly valued by society, results in a beneficial approach to daily life, and provides a valuable shortcut through the complicated nature of modern existence. Consistency allows us to more effectively make decisions and process information. The concept of consistency states that someone who commits to something, orally or in writing, is more likely to honor that commitment. This is especially true for written commitments, as they appear psychologically more concrete and can create hard proof. Someone who commits to a stance tends to behave according to that
Eshkol became the first prime minister to die in office. He was temporarily replaced by Yigal Allon, whose stint lasted less than a month, as the party persuaded Golda Meir to return to political life and become prime minister in March 1969. Meir was Israel's first woman prime minister, and the third in the world (after Sirimavo Bandaranaike and Indira Gandhi). Meir resigned in 1974 after the Agranat Commission published its findings on the Yom Kippur War, even though it had absolved her of blame. Yitzhak Rabin took over, though he also resigned towards the end of the eighth Knesset's term following a series of scandals. Those included the suicide of Housing Minister Avraham Ofer after police began investigating allegations that he had used party funds illegally, and the affair involving Asher Yadlin (the governor-designate of the Bank of Israel), who was sentenced to five years in prison for having accepted bribes. Rabin's wife, Leah, was also found to have had an overseas bank account, which was illegal in Israel at the time. Menachem Begin became the first right-wing prime minister when his Likud won the 1977 elections, and retained the post in the 1981 elections. He resigned in 1983 for health reasons, passing the reins of power to Yitzhak Shamir. After the 1984 elections had proved inconclusive with neither the Alignment nor Likud able to form a government, a national unity government was formed with a rotating prime ministership – Shimon Peres took the first two years, and was replaced by Shamir midway through the Knesset term. Although the 1988 elections produced another national unity government, Shamir was able to take the role alone. Peres made an abortive bid to form a left-wing government in 1990, but failed, leaving Shamir in power until 1992. Rabin became prime minister for the second time when he led Labour to victory in the 1992 elections. After his assassination on 4 November 1995, Peres took over as prime minister. Direct election During the thirteenth Knesset (1992–1996) it was decided to hold a separate ballot for prime minister modeled after American presidential elections. This system was instituted in part because the Israeli electoral system makes it all but impossible for one party to win a majority. While only two parties—Mapai/Labour and Likud—had ever led governments, the large number of parties or factions in a typical Knesset usually prevents one party from winning the 61 seats needed for a majority. In 1996, when the first such election took place, the outcome was a surprise win for Benjamin Netanyahu after election polls predicted that Peres was the winner. However, in the Knesset election held at the same time, Labour won more votes than any other party (27%). Thus Netanyahu, despite his theoretical position of power, needed the support of the religious parties to form a viable government. Ultimately Netanyahu failed to hold the government together, and early elections for both prime minister and the Knesset were called in 1999. Although five candidates intended to run, the three representing minor parties (Benny Begin of Herut – The National Movement, Azmi Bishara of Balad and Yitzhak Mordechai of the Centre Party) dropped out before election day, and Ehud Barak beat Netanyahu in the election. However, the new system again appeared to have failed; although Barak's One Israel alliance (an alliance of Labour, Gesher and Meimad) won more votes than any other party in the Knesset election, they garnered only 26 seats, the lowest ever by a winning party or alliance. Barak needed to form a coalition with six smaller parties to form a government. In early 2001, Barak resigned following the outbreak of the al-Aqsa Intifada. However, the government was not brought down, and only elections for prime minister were necessary. In the election itself, Ariel Sharon of Likud comfortably beat Barak, taking 62.4% of the vote. However, because Likud only had 21 seats in the Knesset, Sharon had to form a national unity government. Following Sharon's victory, it was decided to do away with separate elections for prime minister and return to the previous system. 2003 onwards The 2003 elections were carried out in the same manner as prior to 1996. Likud won 38 seats, the highest by a party for over a decade, and as party leader Sharon was duly appointed Prime Minister. However, towards the end of his term and largely as a result of the deep divisions within Likud over Israel's unilateral disengagement plan, Sharon broke away from his party to form Kadima, managing to maintain his position as prime minister and also becoming the first prime minister not to be a member of either Labour or Likud (or their predecessors). However, he suffered a stroke in January 2006, in the midst of election season, leading Ehud Olmert to become acting prime minister in the weeks leading to the elections. He was voted by the cabinet to be interim prime minister just after the 2006 elections, when Sharon had reached 100 days of incapacitation. He thus became Israel's third interim prime minister, only days before forming his own new government as the official Prime Minister of Israel. In 2008, amid accusations of corruption and challenges from his own party, Olmert resigned. However his successor Tzipi Livni was unable to form a coalition government. In the election in the following year, while Kadima won the most seats, it was the Likud leader Benjamin Netanyahu who was given the task of forming a government. He was able to do so, thus beginning his second term as Prime Minister of Israel. In the 2013 election, the Likud Yisrael Beiteinu alliance emerged as the largest faction. After forming a coalition, Netanyahu secured his third prime ministership. In 2015, Netanyahu managed to stay in power. Multiple disagreements with his coalition members led to the 2019–2021 Israeli political crisis. In 2021, Naftali Bennett became prime minister. Order of succession If the prime minister dies in office, the cabinet chooses an interim prime minister to run the government until a new government is placed in power. Yigal Allon served as interim prime minister following Levi Eshkol's death, as did Shimon Peres following the assassination of Yitzhak Rabin. According to Israeli law, if a prime minister is temporarily incapacitated rather than dies (as was the case following Ariel Sharon's stroke in early 2006), power is transferred to the acting prime minister, until the prime minister recovers (Ehud Olmert took over from Sharon), for	to win a majority. While only two parties—Mapai/Labour and Likud—had ever led governments, the large number of parties or factions in a typical Knesset usually prevents one party from winning the 61 seats needed for a majority. In 1996, when the first such election took place, the outcome was a surprise win for Benjamin Netanyahu after election polls predicted that Peres was the winner. However, in the Knesset election held at the same time, Labour won more votes than any other party (27%). Thus Netanyahu, despite his theoretical position of power, needed the support of the religious parties to form a viable government. Ultimately Netanyahu failed to hold the government together, and early elections for both prime minister and the Knesset were called in 1999. Although five candidates intended to run, the three representing minor parties (Benny Begin of Herut – The National Movement, Azmi Bishara of Balad and Yitzhak Mordechai of the Centre Party) dropped out before election day, and Ehud Barak beat Netanyahu in the election. However, the new system again appeared to have failed; although Barak's One Israel alliance (an alliance of Labour, Gesher and Meimad) won more votes than any other party in the Knesset election, they garnered only 26 seats, the lowest ever by a winning party or alliance. Barak needed to form a coalition with six smaller parties to form a government. In early 2001, Barak resigned following the outbreak of the al-Aqsa Intifada. However, the government was not brought down, and only elections for prime minister were necessary. In the election itself, Ariel Sharon of Likud comfortably beat Barak, taking 62.4% of the vote. However, because Likud only had 21 seats in the Knesset, Sharon had to form a national unity government. Following Sharon's victory, it was decided to do away with separate elections for prime minister and return to the previous system. 2003 onwards The 2003 elections were carried out in the same manner as prior to 1996. Likud won 38 seats, the highest by a party for over a decade, and as party leader Sharon was duly appointed Prime Minister. However, towards the end of his term and largely as a result of the deep divisions within Likud over Israel's unilateral disengagement plan, Sharon broke away from his party to form Kadima, managing to maintain his position as prime minister and also becoming the first prime minister not to be a member of either Labour or Likud (or their predecessors). However, he suffered a stroke in January 2006, in the midst of election season, leading Ehud Olmert to become acting prime minister in the weeks leading to the elections. He was voted by the cabinet to be interim prime minister just after the 2006 elections, when Sharon had reached 100 days of incapacitation. He thus became Israel's third interim prime minister, only days before forming his own new government as the official Prime Minister of Israel. In 2008, amid accusations of corruption and challenges from his own party, Olmert resigned. However his successor Tzipi Livni was unable to form a coalition government. In the election in the following year, while Kadima won the most seats, it was the Likud leader Benjamin Netanyahu who was given the task of forming a government. He was able to do so, thus beginning his second term as Prime Minister of Israel. In the 2013 election, the Likud Yisrael Beiteinu alliance emerged as the largest faction. After forming a coalition, Netanyahu secured his third prime ministership. In 2015, Netanyahu managed to stay in power. Multiple disagreements with his coalition members led to the 2019–2021 Israeli political crisis. In 2021, Naftali Bennett became prime minister. Order of succession If the prime minister dies in office, the cabinet chooses an interim prime minister to run the government until a new government is placed in power. Yigal Allon served as interim prime minister following Levi Eshkol's death, as did Shimon Peres following the assassination of Yitzhak Rabin. According to Israeli law, if a prime minister is temporarily incapacitated rather than dies (as was the case following Ariel Sharon's stroke in early 2006), power is transferred to the acting prime minister, until the prime minister recovers (Ehud Olmert took over from Sharon), for up to 100 days. If the prime minister is declared permanently incapacitated, or that period expires, the president of Israel oversees the process of assembling a new governing coalition, and in the meantime the acting prime minister or other incumbent minister is appointed by the cabinet to serve as interim prime minister. In the case of Sharon, elections were already due to occur within 100 days of the beginning of his coma; thus, the post-election coalition-building process pre-empted the emergency provisions for the selection of a new prime minister. Nevertheless, Olmert was appointed interim prime minister on 16 April 2006, after the elections, just days before he formed a government on 4 May 2006, becoming the official prime minister. Acting, vice and deputy prime minister Aside from the position of Acting Prime Minister, there are also vice prime ministers and deputy prime ministers. Interim government Interim prime minister The interim prime minister (, Rosh HaMemshala Ba-foal lit. "prime minister de facto") is appointed by the government if the incumbent is dead or permanently incapacitated, or if his tenure was ended due to a criminal conviction. Israeli law distinguishes the terms acting prime minister (מלא מקום ראש הממשלה), filling in for the incumbent prime minister, temporarily, and acting in the incumbent's office, while the incumbent is in office, and an interim prime minister in office. Only if the incumbent prime minister becomes temporarily incapacitated will the acting prime minister act in the incumbent's office and will be standing in for him for up to 100 consecutive days, while the incumbent is in office. Legally, the "100 consecutive days" limit, in the language of the law, only stipulates that the incumbent then is deemed to be permanently incapacitated and that the limited time for an acting prime minister to act in the incumbent's office is over. The 1968 law (prior to the 1992 and 2001 basic laws of government) did not impose a time limit on a "temporarily incapacitation" period of the incumbent prime minister, but rather pending the return of the incumbent to resume his duties, and separately addressed only the event of death of the incumbent for appointing an interim prime minister, while failing to address Permanent incapacitation or criminal conviction of the incumbent prime minister. Separately, the law of 2001 stipulates that in any event where the incumbent prime minister becomes permanently incapacitated (either declared as such or "100 consecutive days" limit expired or else), or if the incumbent died or ceased being prime minister due to a criminal conviction, the government that is "deemed to have resigned", to become an interim government, continues to govern until a new government is placed in power, and in the absence of a prime minister in office, they then must vote on one of their incumbent ministers (either the acting prime minister or else) to fully assume office as the interim Prime minister, if he or she meet the requirements. While the acting prime minister must be a Knesset member to meet the requirements, the interim prime minister must be a member of the prime minister's party as well. Until the 2001 basic law: the government, both the acting and interim prime ministers were only required to be a Knesset member in addition to being a member of the Government. However, before and after the 2001 law, an interim prime minister would not be appointed unless the government would be voting on one of their members (either the acting prime minister or else) to be the interim prime minister until a new government is placed in power. In 2006, Ehud Olmert, after standing in for Prime Minister Sharon for 100 consecutive days, as acting prime minister, did not automatically assume office as an interim prime minister. The government voted to appoint him, and in addition, he was also a member of prime minister's party, which enabled them to appoint him to the role. An interim prime minister does not have to form a majority coalition in the Knesset, in order to get their approval vote (as a prime minister is required to do), and can assume office immediately, until a new government is placed in power. Shimon Peres was the foreign minister when Prime Minister Yitzhak Rabin was assassinated, and was voted unanimously to assume office as an interim prime minister until a new Government would be placed in power (that he later formed by himself). Yigal Allon was also voted to be the interim prime minister after Prime Minister Levi Eshkol suddenly died and served until Golda Meir formed her government. Both the interim and acting prime ministers' authorities are identical to those of a prime minister, with the exception of not having the authority to dissolve the Knesset. There are other cases (all other), not pending the situation of the incumbent prime minister's ability to continue to serve, where the Government becomes an interim government, while the incumbent prime minister is in office. In these cases, the incumbent prime minister is commonly referred as an "interim" prime minister, as a reference to change of the legal status only of the government under him. However, legally he is the prime minister, and only the government under him is legally an interim government (see interim government below). Main provision Basic Law: the Government (2001): 30. (b) If the prime minister has died, or is permanently incapacitated, from carrying out his duties, or if his tenure was ended because of an offense, the Government shall designate another of the Ministers who is a member of the Knesset and of the prime minister's faction to be interim prime minister pending the constitution of the new Government. List of interim prime ministers Interim government An 'interim government' (, Memshelet Ma'avar lit. "transitional government") is the same government, having been changed in their legal status, after the death, resignation, permanent incapacitation, or criminal conviction of the prime minister, as well as after the prime minister's request to dissolve the Knesset (Israeli parliament) was published through the president's decree, or after it was defeated by a motion of no confidence (these actions are regarded by the law as "the Government shall be deemed to have resigned"), or after election and before the forming of a new government (legally, "Newly elected Knesset" period), and in all the cases above, it continues to govern as an interim government, until a new government is placed in power, accordingly to the principle of "government continuity", in order to prevent a government void. If the incumbent prime minister can no longer serve (died, permanent incapacitation or criminal conviction), when the government is "deemed to have resigned" to become an interim government, they appoint a different person from their own government to the role of an interim prime minister (either the acting prime minister or else) until a new government is placed in power. This is a legal reference both to the change of a prime minister in office and in same government, a change
can also lessen or suppress criminal sentences. This was of crucial importance when France still operated the death penalty: criminals sentenced to death would generally request that the president commute their sentence to life imprisonment. All decisions of the president must be countersigned by the prime minister, except dissolving the French National Assembly, choice of prime minister, and other dispositions referred to in Article 19. Detailed constitutional powers The constitutional attributions of the president are defined in Title II of the Constitution of France. Article 5: The president of the republic shall see that the Constitution is observed. He shall ensure, by his arbitration, the proper functioning of the public authorities and the continuity of the State. He shall be the guarantor of national independence, territorial integrity and observance of treaties. Article 8: The president of the republic shall appoint the prime minister. He shall terminate the appointment of the prime minister when the latter tenders the resignation of the Government. On the proposal of the prime minister, he shall appoint the other members of the Government and terminate their appointments. Article 9: The president of the republic shall preside over the Council of Ministers. Article 10: The president of the republic shall promulgate acts of parliament within fifteen days following the final adoption of an act and its transmission to the Government. He may, before the expiry of this time limit, ask Parliament to reconsider the act or sections of the Act. Reconsideration shall not be refused. While the President has to sign all acts adopted by parliament into law, he cannot refuse to do so and exercise a kind of right of veto; his only power in that matter is to ask for a single reconsideration of the law by parliament and this power is subject to countersigning by the Prime minister. Article 11: The president could submit laws to the people in a referendum with advice and consent of the cabinet. Article 12: The president of the republic may, after consulting the prime minister and the presidents of the assemblies, declare the National Assembly dissolved. A general election shall take place not less than twenty days and not more than forty days after the dissolution. The National Assembly shall convene as of right on the second Thursday following its election. Should it so convene outside the period prescribed for the ordinary session, a session shall be called by right for a fifteen-day period. No further dissolution shall take place within a year following this election. Article 13: The president of the republic shall sign the ordinances and decrees deliberated upon in the Council of Ministers. He shall make appointments to the civil and military posts of the State. [...] Article 14: The president of the republic shall accredit ambassadors and envoys extraordinary to foreign powers; foreign ambassadors and envoys extraordinary shall be accredited to him. Article 15: The president of the republic shall be commander-in-chief of the armed forces. He shall preside over the higher national defence councils and committees. Article 16: Where the institutions of the republic, the independence of the nation, the integrity of its territory or the fulfilment of its international commitments are under serious and immediate threat, and where the proper functioning of the constitutional public authorities is interrupted, the president of the republic shall take the measures required by these circumstances, after formally consulting the prime minister, the presidents of the assemblies and the Constitutional Council. He shall inform the nation of these measures in a message. The measures must stem from the desire to provide the constitutional public authorities, in the shortest possible time, with the means to carry out their duties. The Constitutional Council shall be consulted with regard to such measures. Parliament shall convene as of right. The National Assembly shall not be dissolved during the exercise of the emergency powers. Article 16, allowing the president a limited form of rule by decree for a limited period of time in exceptional circumstance, has been used only once, by Charles de Gaulle during the Algerian War, from 23 April to 29 September 1961. Article 17: The president of the republic has the right to grant pardon. Article 18: The president of the republic shall communicate with the two assemblies of Parliament by means of messages, which he shall cause to be read and which shall not be the occasion for any debate. He can also give an address in front of the Congress of France in Versailles. Outside sessions, Parliament shall be convened especially for this purpose. Article 19: Acts of the president of the republic, other than those provided for under articles 8 (first paragraph), 11, 12, 16, 18, 54, 56 and 61, shall be countersigned by the prime minister and, where required, by the appropriate ministers. Presidential amnesties Before the 2008 constitutional reform, forbidding them, there was a tradition of so-called "presidential amnesties", which are something of a misnomer: after the election of a president, and of a National Assembly of the same party, parliament would traditionally vote a law granting amnesty for some petty crimes (it was also a way of reducing jail overpopulation). This practice had been increasingly criticized, particularly because it was believed to inspire people to commit traffic offences in the months preceding the election. Such an amnesty law would also authorize the president to designate individuals who have committed certain categories of crimes to be offered amnesty, if certain conditions are met. Such individual measures have been criticized for the political patronage that they allow. The difference between an amnesty and a presidential pardon is that the former clears all subsequent effects of the sentencing, as though the crime had not been committed, while pardon simply relieves the sentenced individual from part or all of the remainder of the sentence. Criminal responsibility and impeachment Articles 67 and 68 organize the regime of criminal responsibility of the president. They were reformed by a 2007 constitutional act in order to clarify a situation that previously resulted in legal controversies. The president of the Republic enjoys immunity during their	measures. Parliament shall convene as of right. The National Assembly shall not be dissolved during the exercise of the emergency powers. Article 16, allowing the president a limited form of rule by decree for a limited period of time in exceptional circumstance, has been used only once, by Charles de Gaulle during the Algerian War, from 23 April to 29 September 1961. Article 17: The president of the republic has the right to grant pardon. Article 18: The president of the republic shall communicate with the two assemblies of Parliament by means of messages, which he shall cause to be read and which shall not be the occasion for any debate. He can also give an address in front of the Congress of France in Versailles. Outside sessions, Parliament shall be convened especially for this purpose. Article 19: Acts of the president of the republic, other than those provided for under articles 8 (first paragraph), 11, 12, 16, 18, 54, 56 and 61, shall be countersigned by the prime minister and, where required, by the appropriate ministers. Presidential amnesties Before the 2008 constitutional reform, forbidding them, there was a tradition of so-called "presidential amnesties", which are something of a misnomer: after the election of a president, and of a National Assembly of the same party, parliament would traditionally vote a law granting amnesty for some petty crimes (it was also a way of reducing jail overpopulation). This practice had been increasingly criticized, particularly because it was believed to inspire people to commit traffic offences in the months preceding the election. Such an amnesty law would also authorize the president to designate individuals who have committed certain categories of crimes to be offered amnesty, if certain conditions are met. Such individual measures have been criticized for the political patronage that they allow. The difference between an amnesty and a presidential pardon is that the former clears all subsequent effects of the sentencing, as though the crime had not been committed, while pardon simply relieves the sentenced individual from part or all of the remainder of the sentence. Criminal responsibility and impeachment Articles 67 and 68 organize the regime of criminal responsibility of the president. They were reformed by a 2007 constitutional act in order to clarify a situation that previously resulted in legal controversies. The president of the Republic enjoys immunity during their term: they cannot be requested to testify before any jurisdiction, they cannot be prosecuted, etc. However, the statute of limitation is suspended during their term, and enquiries and prosecutions can be restarted, at the latest one month after they leave office. The president is not deemed personally responsible for their actions in their official capacity, except where their actions are indicted before the International Criminal Court (France is a member of the ICC and the president is a French citizen as another following the Court's rules) or where impeachment is moved against them. Impeachment can be pronounced by the Republican High Court, a special court convened from both houses of Parliament on the proposal of either House, should the president have failed to discharge their duties in a way that evidently precludes the continuation of their term. Succession and incapacity Upon the death in office, removal, or resignation of the president, the Senate's president takes over as acting president. Alain Poher is the only person to have served in this temporary position, and has done so twice: the first time in 1969 after Charles de Gaulle's resignation and a second time in 1974 after Georges Pompidou's death while in office. In this situation, the president of the Senate becomes Acting President of the Republic; they do not become the new president of the Republic as elected and therefore do not have to resign from their position as President of the Senate. In spite of his title as Acting President of the Republic, Poher is listed in the presidents' gallery on the official presidential website. This is in contrast to acting presidents from the Third Republic. The first round of a new presidential election must be organized no sooner than twenty days and no later than thirty-five days following the vacancy of the presidency. Fifteen days can separate the first and second rounds of a presidential election; this means that the president of the Senate can only act as President of the Republic for a maximum period of fifty days. During this interim period, acting presidents are not allowed to dismiss the national assembly, nor are they allowed to call for a referendum or initiate any constitutional changes. If there is no president of the Senate, the powers of the president of the republic are exercised by the , meaning the Cabinet. This has been interpreted by some constitutional academics as meaning first the prime minister and, if he is himself not able to act, the members of the cabinet in the order of the list of the decree that nominated them. This is in fact unlikely to happen, because if the president of the Senate is not able to act, the Senate will normally name a new president of the Senate, who will act as President of the Republic. During the Third French Republic the president of the Council of Ministers acted as president whenever the office was vacant. According to article 7 of the Constitution, if the presidency becomes vacant for any reason, or if the president becomes incapacitated, upon the request of the , the Constitutional Council may rule, by a majority vote, that the presidency is to be temporarily assumed by the president of the Senate. If the Council rules that the incapacity is permanent, the same procedure as for the resignation is applied, as described above. If the president cannot attend meetings, including meetings of the Council of Ministers, he can ask the prime minister to attend in his stead (Constitution, article 21). This clause has been applied by presidents travelling abroad, ill, or undergoing surgery. During the Second French Republic, there was a vice president. The only person to ever hold the position was Henri Georges Boulay de la Meurthe. Death in office Four French presidents have died in office: Sadi Carnot, who was assassinated by Sante Geronimo Caserio on 25 June 1894, aged 56. Félix Faure, who died on 16 February 1899, aged 58. Paul Doumer, who was assassinated by Paul Gorguloff on 7 May 1932, aged 75, the oldest to die in office. Georges Pompidou, who died on 2 April 1974, aged 62. Pay and official residences The president of the Republic is paid a salary according to a pay grade defined in comparison to the pay grades of the most senior members of the French Civil Service ("out of scale", hors échelle, those whose pay grades are known as letters and not as numeric indices). In addition he is paid a residence stipend of 3%, and a function stipend of 25% on top of the salary and residence indemnity. This gross salary and these indemnities are the same as those of the prime minister, and are 50% higher than the highest paid to other members of the government, which is itself defined as twice the average of the highest (pay grade G) and the lowest (pay grade A1) salaries in the "out of scale" pay grades. Using the 2008 "out of scale" pay grades, it amounts to a monthly pay of 20,963 euros, which fits the 19,000 euros quoted to the press in early 2008. Using the pay grades starting from 1 July 2009, this amounts to a gross monthly pay of €21,131. The salary and the residence stipend are taxable for income tax. The official residence and office of the president is the Élysée Palace in Paris. Other presidential residences include: the Hôtel de Marigny, standing next to the Élysée Palace, houses foreign official guests; the Château de Rambouillet is normally open to visitors when not used for (rare) official meetings; the Domaine national de Marly is normally open to visitors when not used for (rare) official meetings; the Fort de Brégançon, in Southeastern France, is the official presidential vacation residence. In 2013, it became a national monument and is opened to the public some moments since 2014. The French president's private quarters there are still available for his use. La Lanterne became an official presidential vacation residence in 2007. Latest election Pension and benefits According to French law, former presidents of the Republic have guaranteed lifetime pension defined according to the pay grade of the Councillors of State, a courtesy diplomatic passport, and, according to the French Constitution (Article 56), membership of the Constitutional Council. They also get personnel, an apartment and/or office, and other amenities, though the legal basis for these is disputed. The current system for providing personnel and other amenities to the former French presidents was devised in 1981 by Michel Charasse, then advisor to President François Mitterrand, in order to care for former president Valéry Giscard d'Estaing and the widow of former President Georges Pompidou. In 2008, according to an answer by the services of the prime minister to a question from René Dosière, a member of the National Assembly, the facilities comprised: a security detail, a car with a chauffeur, first class train tickets and an office or housing space, as well as a two people who service the space. In addition, funds are available for seven permanent assistants. President Hollande announced a reform of the system in 2016. Former presidents of France will no longer receive a car with chauffeur and the personnel in their living space was cut as well. Additionally, the number of assistants available for their use has been reduced, but a state flat or house remains available for former officeholders. Train tickets are also available if the trip is justified by the office of the former officeholder as part of official business. The security personnel around former presidents of France remained unchanged. Lists relating to the presidents of France List of French non-presidential heads of state by tenure List of presidents of France List of presidents of France by tenure References Further reading How Powerful Is France's
samples of explosive brought to the U.S. by the Tizard Mission had already been packaged by the SOE ready for dropping via parachute container to the French Resistance and were therefore labeled in French, as Explosif Plastique. It is still referred to by this name in France and also by some Americans. Types Composition C The British used a plastic explosive during World War II as a demolition charge. The specific explosive, Composition C, was 88.3% RDX and 11.7% non-oily, non-explosive plasticizer. The material was plastic between 0 and 40 degrees C, but was brittle at colder temperatures and gummy at higher temperatures. Composition C was superseded by Composition C2, which used a mixture of 80% RDX and 20% plasticizer. Composition C2 had a wider temperature range at which it remained plastic, from −30 to 52 degrees C. Composition C2 was replaced by Composition C3, which was a mixture of 77% RDX and 23% explosive plasticizer. C3 was effective but proved to be too brittle in cold weather and was replaced with C4. There are three classes of C4, with varying amounts of RDX and polyisobutylene. List of plastic explosives Australia: PE4, PE4-MC Austria: KNAUERIT SPEZIAL Czech Republic: Semtex-1H (orange-colored), Semtex 1A (red-colored), Semtex 10 (also called Pl Np 10; black-colored), Pl Hx 30 (gray-colored) Finland: PENO France: Hexomax, Composition C-4 PLASTRITE (FORMEX P1, Pla Np 87) Germany: Sprengkörper DM12, P8301, Seismoplast 1 (Sprengmasse, formbar) Netherlands: Knaverit S1 (light orange-colored) Greece: C3, C4 India: PEK-1 Israel: Semtex Italy: T-4 Plastico Norway: NM91 (HMX), C4, DPX10 (PE8) Pakistan: PE-3A Poland: PMW, NITROLIT Russia: PVV-5A Plastic Explosive Slovakia: CHEMEX (Composition C-4 equivalent), TVAREX 4A, Pl Hx 30 South Africa: PE9 (Composition C-4 equivalent) Sweden: Sprängdeg m/46, NSP711 (PETN-based), NSH711 (cyclonite-based) Switzerland: PLASTEX produced by SSE Turkey: Composition C-4 United Kingdom MOD explosives: PE2 (sheet explosive, superseded by SX2), PE3A (superseded by PE4), PE4 (pure to off-white slab, block, or stick, superseded by PE7 and PE8 in MOD usage), SX2 (sheet explosive, superseded by SX4), PE7 (pure to off-white slab or block, Hexomax variant), PE8 (pure to off-white slab or block, current in-service slab charge), SX4 (sheet explosive),	the art" either what he meant by plasticity or why it may be advantageous, as he only explains why his plastic explosive is superior to others of that type. One of the simplest plastic explosives was Nobel's Explosive No. 808, also known as Nobel 808 (often just called Explosive 808 in the British Armed Forces during the Second World War), developed by the British company Nobel Chemicals Ltd well before World War II. It had the appearance of green plasticine with a distinctive smell of almonds. During World War II it was extensively used by the British Special Operations Executive (SOE) at Aston House for sabotage missions. It is also the explosive used in HESH anti-tank shells and was an essential factor in the devising of the Gammon grenade. Captured SOE-supplied Nobel 808 was the explosive used in the failed 20 July plot assassination attempt on Adolf Hitler in 1944. During and after World War II a number of new RDX-based explosives were developed, including Compositions C, C2, and eventually C3. Together with RDX, these incorporate various plasticizers to decrease sensitivity and make the composition plastic. The origin of the obsolete term "plastique" dates back to the Nobel 808 explosive introduced to the U.S. by the British in 1940. The samples of explosive brought to the U.S. by the Tizard Mission had already been packaged by the SOE ready for dropping via parachute container to the French Resistance and were therefore labeled in French, as Explosif Plastique. It is still referred to by this name in France and also by some Americans. Types Composition C The British used a plastic explosive during World War II as a demolition charge. The specific explosive, Composition C, was 88.3% RDX and 11.7% non-oily, non-explosive plasticizer. The material was plastic between 0 and 40 degrees C, but was brittle at colder temperatures and gummy at higher temperatures. Composition C was superseded by Composition C2, which used a mixture of 80% RDX and 20% plasticizer. Composition C2 had a wider temperature range at which it remained plastic, from −30 to 52 degrees C. Composition C2 was replaced by Composition C3, which was a mixture of 77% RDX and 23% explosive plasticizer. C3 was effective but proved to be too brittle in cold weather and was replaced with C4. There are three classes of C4, with varying amounts of RDX and polyisobutylene. List of plastic explosives Australia: PE4, PE4-MC Austria:
a metalanguage by which it is explained, and therefore deconstruction itself is in danger of becoming a metalanguage, thus exposing all languages and discourse to scrutiny. Barthes' other works contributed deconstructive theories about texts. Derrida's lecture at Johns Hopkins The occasional designation of post-structuralism as a movement can be tied to the fact that mounting criticism of Structuralism became evident at approximately the same time that Structuralism became a topic of interest in universities in the United States. This interest led to a colloquium at Johns Hopkins University in 1966 titled "The Languages of Criticism and the Sciences of Man", to which such French philosophers as Jacques Derrida, Roland Barthes, and Jacques Lacan were invited to speak. Derrida's lecture at that conference, "Structure, Sign, and Play in the Human Sciences", was one of the earliest to propose some theoretical limitations to Structuralism, and to attempt to theorize on terms that were clearly no longer structuralist. The element of "play" in the title of Derrida's essay is often erroneously interpreted in a linguistic sense, based on a general tendency towards puns and humour, while social constructionism as developed in the later work of Michel Foucault is said to create play in the sense of strategic agency by laying bare the levers of historical change. Many see the importance of Foucault's work to be in its synthesis of this social/historical account of the operation of power. Criticism Some observers from outside of the post-structuralist camp have questioned the rigour and legitimacy of the field. American philosopher John Searle suggested in 1990: "The spread of 'poststructuralist' literary theory is perhaps the best-known example of a silly but non-catastrophic phenomenon." Similarly, physicist Alan Sokal in 1997 criticized "the postmodernist/poststructuralist gibberish that is now hegemonic in some sectors of the American academy." Literature scholar Norman Holland in 1992 saw post-structuralism as flawed due to reliance on Saussure's linguistic model, which was seriously challenged by the 1950s and was soon abandoned by linguists:Saussure's views are not held, so far as I know, by modern linguists, only by literary critics and the occasional philosopher. [Strict adherence to Saussure] has elicited wrong film and literary theory on a grand scale. One can find dozens of books of literary theory bogged down in signifiers and signifieds, but only a handful that refers to Chomsky."David Foster Wallace	occasional designation of post-structuralism as a movement can be tied to the fact that mounting criticism of Structuralism became evident at approximately the same time that Structuralism became a topic of interest in universities in the United States. This interest led to a colloquium at Johns Hopkins University in 1966 titled "The Languages of Criticism and the Sciences of Man", to which such French philosophers as Jacques Derrida, Roland Barthes, and Jacques Lacan were invited to speak. Derrida's lecture at that conference, "Structure, Sign, and Play in the Human Sciences", was one of the earliest to propose some theoretical limitations to Structuralism, and to attempt to theorize on terms that were clearly no longer structuralist. The element of "play" in the title of Derrida's essay is often erroneously interpreted in a linguistic sense, based on a general tendency towards puns and humour, while social constructionism as developed in the later work of Michel Foucault is said to create play in the sense of strategic agency by laying bare the levers of historical change. Many see the importance of Foucault's work to be in its synthesis of this social/historical account of the operation of power. Criticism Some observers from outside of the post-structuralist camp have questioned the rigour and legitimacy of the field. American philosopher John Searle suggested in 1990: "The spread of 'poststructuralist' literary theory is perhaps the best-known example of a silly but non-catastrophic phenomenon." Similarly, physicist Alan Sokal in 1997 criticized "the postmodernist/poststructuralist gibberish that is now hegemonic in some sectors of the American academy." Literature scholar Norman Holland in 1992 saw post-structuralism as flawed due to reliance on Saussure's linguistic model, which was seriously challenged by the 1950s and was soon abandoned by linguists:Saussure's views are not held, so far as I know, by modern linguists, only by literary critics and the occasional philosopher. [Strict adherence to Saussure] has elicited wrong film and literary theory on a grand scale. One can find dozens of books of literary theory bogged down in signifiers and signifieds, but only a handful that refers to Chomsky."David Foster Wallace wrote: See also Authors The following are often said to be post-structuralists, or to have had a post-structuralist period: Kathy Acker Jean Baudrillard Roland Barthes Wendy Brown Judith Butler Rey Chow Hélène Cixous Gilles Deleuze Jacques Derrida Umberto Eco John Fiske Michel Foucault René Girard Félix Guattari Luce Irigaray Julia Kristeva Teresa de Lauretis Sarah Kofman Philippe Lacoue-Labarthe Jean-François Lyotard Chantal Mouffe Jean-Luc Nancy Avital Ronell Bernard Stiegler
used broadly, with their meanings defined in terms of the phases of various peace process mechanisms blurring and overlapping in practice. Institutions The construction of international institutions, especially during the twentieth century, has to a large degree been motivated by the desire to provide a broad global context of peacebuilding. This includes the League of Nations and the United Nations, and regional institutions such as the European Union. Institutions involved in encouraging or overseeing some of the steps in specific peace processes include the United Nations Department of Peace Operations. Mechanisms Many specific peace mechanisms can comprise the elements of peace processes. The Peace Accords Matrix of the Kroc Institute for International Peace Studies at the University of Notre Dame, United States, lists some of these as amnesties, ceasefires, arms embargoes, truth and reconciliation commissions and reforms of the constitution, or of military, police, judicial or educational institutions or of the media. Other mechanisms include prisoner exchanges, confidence-building measures, humanitarian corridors, peace treaties and transitional justice. Criticism Edward Luttwak argues that conventional wars should not be interrupted before they could burn themselves out and the preconditions for a long-lasting peace are established. Stable peace settlement is possible only with the exhaustion of belligerents or the decisive victory of one side. "Hopes for military success must fade for accommodation to become more attractive than further combat," but premature ceasefires prevent belligerents from exhaustion and let them rearm their forces. That in turn prolongs war and leads to the	Military methods by globally organised military forces of stopping a local armed conflict are typically classed as peace enforcement. Reorganisation The prevention of the repeat of a solved conflict (as well as the preventing of an armed conflict from occurring at all) is usually classed as peacebuilding. UNDPO defines peacebuilding to include "measures [that] address core issues that effect the functioning of society and the State". The use of neutral military forces to sustain ceasefires during this phase, typically by United Nations peacekeeping forces, can be referred to as peacekeeping. Overlapping definitions The terms peacemaking, peacekeeping and peacebuilding tend to be used broadly, with their meanings defined in terms of the phases of various peace process mechanisms blurring and overlapping in practice. Institutions The construction of international institutions, especially during the twentieth century, has to a large degree been motivated by the desire to provide a broad global context of peacebuilding. This includes the League of Nations and the United Nations, and regional institutions such as the European Union. Institutions involved in encouraging or overseeing some of the steps in specific peace processes include the United Nations Department of Peace