title: Magnetometer

text: The magnetic field induces a sine wave in a rotating coil. The amplitude of the signal is proportional to the strength of the field, provided it is uniform, and to the sine of the angle between the rotation axis of the coil and the field lines. This type of magnetometer is obsolete.


title: Magnetometer

text: The most common magnetic sensing devices are solid-state Hall effect sensors. These sensors produce a voltage proportional to the applied magnetic field and also sense polarity. They are used in applications where the magnetic field strength is relatively large, such as in anti-lock braking systems in cars, which sense wheel rotation speed via slots in the wheel disks.


title: Magnetometer

text: These are made of thin strips of Permalloy, a high magnetic permeability, nickel-iron alloy, whose electrical resistance varies with a change in magnetic field. They have a well-defined axis of sensitivity, can be produced in 3-D versions and can be mass-produced as an integrated circuit. They have a response time of less than 1 microsecond and can be sampled in moving vehicles up to 1,000 times/second. They can be used in compasses that read within 1°, for which the underlying sensor must reliably resolve 0.1°.


title: Magnetometer

text: The fluxgate magnetometer was invented by H. Aschenbrenner and G. Goubau in 1936. A team at Gulf Research Laboratories led by Victor Vacquier developed airborne fluxgate magnetometers to detect submarines during World War II and after the war confirmed the theory of plate tectonics by using them to measure shifts in the magnetic patterns on the sea floor.


title: Magnetometer

text: A fluxgate magnetometer consists of a small magnetically susceptible core wrapped by two coils of wire. An alternating electric current is passed through one coil, driving the core through an alternating cycle of magnetic saturation; i.e., magnetised, unmagnetised, inversely magnetised, unmagnetised, magnetised, and so forth. This constantly changing field induces an electric current in the second coil, and this output current is measured by a detector. In a magnetically neutral background, the input and output currents match. However, when the core is exposed to a background field, it is more easily saturated in alignment with that field and less easily saturated in opposition to it. Hence the alternating magnetic field, and the induced output current, are out of step with the input current. The extent to which this is the case depends on the strength of the background magnetic field. Often, the current in the output coil is integrated, yielding an output analog voltage proportional to the magnetic field.


title: Magnetometer

text: A wide variety of sensors are currently available and used to measure magnetic fields. Fluxgate compasses and gradiometers measure the direction and magnitude of magnetic fields. Fluxgates are affordable, rugged and compact with miniaturization recently advancing to the point of complete sensor solutions in the form of IC chips, including examples from both academia and industry. This, plus their typically low power consumption makes them ideal for a variety of sensing applications. Gradiometers are commonly used for archaeological prospecting and unexploded ordnance (UXO) detection such as the German military's popular "Foerster".


title: Magnetometer

text: The typical fluxgate magnetometer consists of a "sense" (secondary) coil surrounding an inner "drive" (primary) coil that is closely wound around a highly permeable core material, such as mu-metal or permalloy. An alternating current is applied to the drive winding, which drives the core in a continuous repeating cycle of saturation and unsaturation. To an external field, the core is alternately weakly permeable and highly permeable. The core is often a toroidally wrapped ring or a pair of linear elements whose drive windings are each wound in opposing directions. Such closed flux paths minimise coupling between the drive and sense windings. In the presence of an external magnetic field, with the core in a highly permeable state, such a field is locally attracted or gated (hence the name fluxgate) through the sense winding. When the core is weakly permeable, the external field is less attracted. This continuous gating of the external field in and out of the sense winding induces a signal in the sense winding, whose principal frequency is twice that of the drive frequency, and whose strength and phase orientation vary directly with the external-field magnitude and polarity.


title: Magnetometer

text: There are additional factors that affect the size of the resultant signal. These factors include the number of turns in the sense winding, magnetic permeability of the core, sensor geometry, and the gated flux rate of change with respect to time.


title: Magnetometer

text: Phase synchronous detection is used to extract these harmonic signals from the sense winding and convert them into a DC voltage proportional to the external magnetic field. Active current feedback may also be employed, such that the sense winding is driven to counteract the external field. In such cases, the feedback current varies linearly with the external magnetic field and is used as the basis for measurement. This helps to counter inherent non-linearity between the applied external field strength and the flux gated through the sense winding.


title: Magnetometer

text: SQUIDs, or superconducting quantum interference devices, measure extremely small changes in magnetic fields. They are very sensitive vector magnetometers, with noise levels as low as 3 fT Hz in commercial instruments and 0.4 fT Hz in experimental devices. Many liquid-helium-cooled commercial SQUIDs achieve a flat noise spectrum from near DC (less than 1 Hz) to tens of kilohertz, making such devices ideal for time-domain biomagnetic signal measurements. SERF atomic magnetometers demonstrated in laboratories so far reach competitive noise floor but in relatively small frequency ranges.


title: Magnetometer

text: SQUID magnetometers require cooling with liquid helium () or liquid nitrogen () to operate, hence the packaging requirements to use them are rather stringent both from a thermal-mechanical as well as magnetic standpoint. SQUID magnetometers are most commonly used to measure the magnetic fields produced by laboratory samples, also for brain or heart activity (magnetoencephalography and magnetocardiography, respectively). Geophysical surveys use SQUIDs from time to time, but the logistics of cooling the SQUID are much more complicated than other magnetometers that operate at room temperature.


title: Magnetometer

text: Magnetometers based on atomic gasses can perform vector measurements of the magnetic field in the low field regime, where the decay of the atomic coherence becomes faster than the Larmor frequency. The physics of such magnetometers is based on the Hanle effect. Such zero-field optically pumped magnetometers have been tested in various configurations and with different atomic species, notably alkali (potassium, rubidium and cesium), helium and mercury. For the case of alkali, the coherence times were greatly limited due to spin-exchange relaxation. A major breakthrough happened at the beginning of the 2000 decade, Romalis group in Princeton demonstrated that in such a low field regime, alkali coherence times can be greatly enhanced if a high enough density can be reached by high temperature heating, this is the so-called SERF effect.


title: Magnetometer

text: The main interest of optically-pumped magnetometers is to replace SQUID magnetometers in applications where cryogenic cooling is a drawback. This is notably the case of medical imaging where such cooling imposes a thick thermal insulation, strongly affecting the amplitude of the recorded biomagnetic signals. Several startup companies are currently developing optically pumped magnetometers for biomedical applications: those of TwinLeaf, quSpin and FieldLine being based on alkali vapors, and those of Mag4Health on metastable helium-4.


title: Magnetometer

text: At sufficiently high atomic density, extremely high sensitivity can be achieved. Spin-exchange-relaxation-free (SERF) atomic magnetometers containing potassium, caesium, or rubidium vapor operate similarly to the caesium magnetometers described above, yet can reach sensitivities lower than 1 fT Hz. The SERF magnetometers only operate in small magnetic fields. The Earth's field is about 50 µT; SERF magnetometers operate in fields less than 0.5 µT.


title: Magnetometer

text: Large volume detectors have achieved a sensitivity of 200 aT Hz. This technology has greater sensitivity per unit volume than SQUID detectors. The technology can also produce very small magnetometers that may in the future replace coils for detecting radio-frequency magnetic fields. This technology may produce a magnetic sensor that has all of its input and output signals in the form of light on fiber-optic cables. This lets the magnetic measurement be made near high electrical voltages.


title: Magnetometer

text: The calibration of magnetometers is usually performed by means of coils which are supplied by an electrical current to create a magnetic field. It allows to characterize the sensitivity of the magnetometer (in terms of V/T). In many applications the homogeneity of the calibration coil is an important feature. For this reason, coils like Helmholtz coils are commonly used either in a single axis or a three axis configuration. For demanding applications a high homogeneity magnetic field is mandatory, in such cases magnetic field calibration can be performed using a Maxwell coil, cosine coils, or calibration in the highly homogenous Earth's magnetic field.


title: Magnetometer

text: Magnetometers have a very diverse range of applications, including locating objects such as submarines, sunken ships, hazards for tunnel boring machines, hazards in coal mines, unexploded ordnance, toxic waste drums, as well as a wide range of mineral deposits and geological structures. They also have applications in heart beat monitors, weapon systems positioning, sensors in anti-locking brakes, weather prediction (via solar cycles), steel pylons, drill guidance systems, archaeology, plate tectonics and radio wave propagation and planetary exploration. Laboratory magnetometers determine the magnetic dipole moment of a magnetic sample, typically as a function of temperature, magnetic field, or other parameter. This helps to reveal its magnetic properties such as ferromagnetism, antiferromagnetism, superconductivity, or other properties that affect magnetism.


title: Magnetometer

text: Depending on the application, magnetometers can be deployed in spacecraft, aeroplanes ("fixed wing" magnetometers), helicopters ("stinger" and "bird"), on the ground ("backpack"), towed at a distance behind quad bikes(ATVs) on a ("sled" or "trailer"), lowered into boreholes ("tool", "probe" or "sonde") and towed behind boats ("tow fish").


title: Magnetometer

text: Magnetometers are used to measure or monitor mechanical stress in ferromagnetic materials. Mechanical stress will improve alignment of magnetic domains in microscopic scale that will raise the magnetic field measured close to the material by magnetometers. There are different hypothesis about stress-magnetisation relationship. However the effect of mechanical stress on measured magnetic field near the specimen is claimed to be proven in many scientific publications. There have been efforts to solve the inverse problem of magnetisation-stress resolution in order to quantify the stress based on measured magnetic field.


title: Magnetometer

text: Magnetometers are used extensively in experimental particle physics to measure the magnetic field of pivotal components such as the concentration or focusing beam-magnets.


title: Magnetometer

text: Magnetometers are also used to detect archaeological sites, shipwrecks, and other buried or submerged objects. Fluxgate gradiometers are popular due to their compact configuration and relatively low cost. Gradiometers enhance shallow features and negate the need for a base station. Caesium and Overhauser magnetometers are also very effective when used as gradiometers or as single-sensor systems with base stations.


title: Magnetometer

text: The TV program "Time Team" popularised 'geophys', including magnetic techniques used in archaeological work to detect fire hearths, walls of baked bricks and magnetic stones such as basalt and granite. Walking tracks and roadways can sometimes be mapped with differential compaction in magnetic soils or with disturbances in clays, such as on the Great Hungarian Plain. Ploughed fields behave as sources of magnetic noise in such surveys.


title: Magnetometer

text: Magnetometers can give an indication of auroral activity before the light from the aurora becomes visible. A grid of magnetometers around the world constantly measures the effect of the solar wind on the Earth's magnetic field, which is then published on the K-index.


title: Magnetometer

text: While magnetometers can be used to help map basin shape at a regional scale, they are more commonly used to map hazards to coal mining, such as basaltic intrusions (dykes, sills, and volcanic plug) that destroy resources and are dangerous to longwall mining equipment. Magnetometers can also locate zones ignited by lightning and map siderite (an impurity in coal).


title: Magnetometer

text: The best survey results are achieved on the ground in high-resolution surveys (with approximately 10 m line spacing and 0.5 m station spacing). Bore-hole magnetometers using a Ferret can also assist when coal seams are deep, by using multiple sills or looking beneath surface basalt flows.


title: Magnetometer

text: Modern surveys generally use magnetometers with GPS technology to automatically record the magnetic field and their location. The data set is then corrected with data from a second magnetometer (the base station) that is left stationary and records the change in the Earth's magnetic field during the survey.


title: Magnetometer

text: Magnetometers are used in directional drilling for oil or gas to detect the azimuth of the drilling tools near the drill. They are most often paired with accelerometers in drilling tools so that both the inclination and azimuth of the drill can be found.


title: Magnetometer

text: For defensive purposes, navies use arrays of magnetometers laid across sea floors in strategic locations (i.e. around ports) to monitor submarine activity. The Russian Alfa-class titanium submarines were designed and built at great expense to thwart such systems (as pure titanium is non-magnetic).


title: Magnetometer

text: Military submarines are degaussed—by passing through large underwater loops at regular intervals—to help them escape detection by sea-floor monitoring systems, magnetic anomaly detectors, and magnetically-triggered mines. However, submarines are never completely de-magnetised. It is possible to tell the depth at which a submarine has been by measuring its magnetic field, which is distorted as the pressure distorts the hull and hence the field. Heating can also change the magnetization of steel.


title: Magnetometer

text: Submarines tow long sonar arrays to detect ships, and can even recognise different propeller noises. The sonar arrays need to be accurately positioned so they can triangulate direction to targets (e.g. ships). The arrays do not tow in a straight line, so fluxgate magnetometers are used to orient each sonar node in the array.


title: Magnetometer

text: Fluxgates can also be used in weapons navigation systems, but have been largely superseded by GPS and ring laser gyroscopes.


title: Magnetometer

text: Magnetometers such as the German Foerster are used to locate ferrous ordnance. Caesium and Overhauser magnetometers are used to locate and help clean up old bombing and test ranges.


title: Magnetometer

text: Magnetometric surveys can be useful in defining magnetic anomalies which represent ore (direct detection), or in some cases gangue minerals associated with ore deposits (indirect or inferential detection). This includes iron ore, magnetite, hematite, and often pyrrhotite.


title: Magnetometer

text: Developed countries such as Australia, Canada and USA invest heavily in systematic airborne magnetic surveys of their respective continents and surrounding oceans, to assist with map geology and in the discovery of mineral deposits. Such aeromag surveys are typically undertaken with 400 m line spacing at 100 m elevation, with readings every 10 meters or more. To overcome the asymmetry in the data density, data is interpolated between lines (usually 5 times) and data along the line is then averaged. Such data is gridded to an 80 m × 80 m pixel size and image processed using a program like ERMapper. At an exploration lease scale, the survey may be followed by a more detailed helimag or crop duster style fixed wing at 50 m line spacing and 50 m elevation (terrain permitting). Such an image is gridded on a 10 x 10 m pixel, offering 64 times the resolution.


title: Magnetometer

text: Where targets are shallow (<200 m), aeromag anomalies may be followed up with ground magnetic surveys on 10 m to 50 m line spacing with 1 m station spacing to provide the best detail (2 to 10 m pixel grid) (or 25 times the resolution prior to drilling).


title: Magnetometer

text: Magnetic fields from magnetic bodies of ore fall off with the inverse distance cubed (dipole target), or at best inverse distance squared (magnetic monopole target). One analogy to the resolution-with-distance is a car driving at night with lights on. At a distance of 400 m one sees one glowing haze, but as it approaches, two headlights, and then the left blinker, are visible.


title: Magnetometer

text: There are many challenges interpreting magnetic data for mineral exploration. Multiple targets mix together like multiple heat sources and, unlike light, there is no magnetic telescope to focus fields. The combination of multiple sources is measured at the surface. The geometry, depth, or magnetisation direction (remanence) of the targets are also generally not known, and so multiple models can explain the data.


title: Magnetometer

text: Potent by Geophysical Software Solutions is a leading magnetic (and gravity) interpretation package used extensively in the Australian exploration industry.


title: Magnetometer

text: Magnetometers assist mineral explorers both directly (i.e., gold mineralisation associated with magnetite, diamonds in kimberlite pipes) and, more commonly, indirectly, such as by mapping geological structures conducive to mineralisation (i.e., shear zones and alteration haloes around granites).


title: Magnetometer

text: Airborne Magnetometers detect the change in the Earth's magnetic field using sensors attached to the aircraft in the form of a "stinger" or by towing a magnetometer on the end of a cable. The magnetometer on a cable is often referred to as a "bomb" because of its shape. Others call it a "bird".


title: Magnetometer

text: Because hills and valleys under the aircraft make the magnetic readings rise and fall, a radar altimeter keeps track of the transducer's deviation from the nominal altitude above ground. There may also be a camera that takes photos of the ground. The location of the measurement is determined by also recording a GPS.


title: Magnetometer

text: Many smartphones contain miniaturized microelectromechanical systems (MEMS) magnetometers which are used to detect magnetic field strength and are used as compasses. The iPhone 3GS has a magnetometer, a magnetoresistive permalloy sensor, the AN-203 produced by Honeywell. In 2009, the price of three-axis magnetometers dipped below US$1 per device and dropped rapidly. The use of a three-axis device means that it is not sensitive to the way it is held in orientation or elevation. Hall effect devices are also popular.


title: Magnetometer

text: Researchers at Deutsche Telekom have used magnetometers embedded in mobile devices to permit touchless 3D interaction. Their interaction framework, called MagiTact, tracks changes to the magnetic field around a cellphone to identify different gestures made by a hand holding or wearing a magnet.


title: Magnetometer

text: Seismic methods are preferred to magnetometers as the primary survey method for oil exploration although magnetic methods can give additional information about the underlying geology and in some environments evidence of leakage from traps. Magnetometers are also used in oil exploration to show locations of geologic features that make drilling impractical, and other features that give geophysicists a more complete picture of stratigraphy.


title: Magnetometer

text: A three-axis fluxgate magnetometer was part of the "Mariner 2" and "Mariner 10" missions. A dual technique magnetometer is part of the "Cassini–Huygens" mission to explore Saturn. This system is composed of a vector helium and fluxgate magnetometers. Magnetometers were also a component instrument on the Mercury "MESSENGER" mission. A magnetometer can also be used by satellites like GOES to measure both the magnitude and direction of the magnetic field of a planet or moon.


title: Magnetometer

text: Systematic surveys can be used to in searching for mineral deposits or locating lost objects. Such surveys are divided into:


title: Magnetometer

text: On the base of space measured distribution of magnetic field parameters (e.g. amplitude or direction), the magnetovision images may be generated. Such presentation of magnetic data is very useful for further analyse and data fusion.


title: Magnetometer

text: Magnetic gradiometers are pairs of magnetometers with their sensors separated, usually horizontally, by a fixed distance. The readings are subtracted to measure the difference between the sensed magnetic fields, which gives the field gradients caused by magnetic anomalies. This is one way of compensating both for the variability in time of the Earth's magnetic field and for other sources of electromagnetic interference, thus allowing for more sensitive detection of anomalies. Because nearly equal values are being subtracted, the noise performance requirements for the magnetometers is more extreme.


title: Magnetometer

text: Gradiometers enhance shallow magnetic anomalies and are thus good for archaeological and site investigation work. They are also good for real-time work such as unexploded ordnance (UXO) location. It is twice as efficient to run a base station and use two (or more) mobile sensors to read parallel lines simultaneously (assuming data is stored and post-processed). In this manner, both along-line and cross-line gradients can be calculated.


title: Magnetometer

text: In traditional mineral exploration and archaeological work, grid pegs placed by theodolite and tape measure were used to define the survey area. Some UXO surveys used ropes to define the lanes. Airborne surveys used radio triangulation beacons, such as Siledus.


title: Magnetometer

text: Non-magnetic electronic hipchain triggers were developed to trigger magnetometers. They used rotary shaft encoders to measure distance along disposable cotton reels.


title: Magnetometer

text: Magnetic surveys can suffer from noise coming from a range of sources. Different magnetometer technologies suffer different kinds of noise problems.


title: Magnetometer

text: Some total field sensors give different readings depending on their orientation. Magnetic materials in the sensor itself are the primary cause of this error. In some magnetometers, such as the vapor magnetometers (caesium, potassium, etc.), there are sources of heading error in the physics that contribute small amounts to the total heading error.


title: Magnetometer

text: Console noise comes from magnetic components on or within the console. These include ferrite in cores in inductors and transformers, steel frames around LCDs, legs on IC chips and steel cases in disposable batteries. Some popular MIL spec connectors also have steel springs.


title: Magnetometer

text: Operators must take care to be magnetically clean and should check the 'magnetic hygiene' of all apparel and items carried during a survey. Akubra hats are very popular in Australia, but their steel rims must be removed before use on magnetic surveys. Steel rings on notepads, steel capped boots and steel springs in overall eyelets can all cause unnecessary noise in surveys. Pens, mobile phones and stainless steel implants can also be problematic.


title: Magnetometer

text: The magnetic response (noise) from ferrous object on the operator and console can change with heading direction because of induction and remanence. Aeromagnetic survey aircraft and quad bike systems can use special compensators to correct for heading error noise.


title: Magnetometer

text: Heading errors look like herringbone patterns in survey images. Alternate lines can also be corrugated.


title: Magnetometer

text: Recording data and image processing is superior to real-time work because subtle anomalies often missed by the operator (especially in magnetically noisy areas) can be correlated between lines, shapes and clusters better defined. A range of sophisticated enhancement techniques can also be used. There is also a hard copy and need for systematic coverage.


title: Magnetometer

text: The Magnetometer Navigation (MAGNAV) algorithm was initially running as a flight experiment in 2004. Later on, diamond magnetometers were developed by the United States Air Force Research Laboratory (AFRL) as a better method of navigation which cannot be jammed by the enemy.


title: Charles, Prince Napoléon

text: Charles, Prince Napoléon ("Charles Marie Jérôme Victor Napoléon"; born 19 October 1950 in Boulogne-Billancourt, France) is a French politician, who is the disputed head of the Imperial House of France and as such, heir to the rights and legacy established by his great-great-granduncle, Emperor Napoléon I. Other Bonapartists consider his son, Jean-Christophe, to be the current head of the house and heir. He would be known as Napoleon VII.


title: Charles, Prince Napoléon

text: Charles was the elder son of the late Louis, Prince Napoléon (1914–1997), and as such a great-great-grandson in the male line of Jérôme Bonaparte, King of Westphalia, Napoléon's youngest brother. As neither Napoléon I nor Napoléon III of France has surviving legitimate issue in the male line, Jérôme's descendants represent the only Imperial Bonapartes still living. (The American Bonapartes were senior in descent from King Jérôme, but the last male of that line died in 1945, and the branch was never considered dynastic in France).


title: Charles, Prince Napoléon

text: In 2011, a study of DNA extracted from Napoleon I's beard and compared to that of Charles was found to match substantially, which established that Charles was a member of the male line of the Imperial House of Bonaparte. (In 2013, published scholarship comparing DNA haplotype evidence taken from Emperor Napoleon I; Prince Charles; and a descendant of Napoleon's reputed son, Count Alexandre Colonna-Walewski, verified Walewski's descent in the genetic male line from Napoleon I's patriline, but Walewski's mother was never married to the emperor and Alexandre was raised as the legal son of her husband.)


title: Charles, Prince Napoléon

text: Charles's mother was Alix de Foresta (born 4 April 1926), daughter of Albéric, "comte" de Foresta. Although she was the only consort of the surviving Imperial line not born a princess, her family had been nobles in Lombardy since the 13th century, becoming counts palatine in 1330, constables of Venice in 1425, then retainers of the powerful Doria family in Genoa. They settled in Provence, France early in the 16th century, where they acquired twenty-two manors and the title of marquis by 1651. Ironically, the Forestas distinguished themselves during the French Restoration as courtiers loyal to the House of Bourbon, and to Henri, comte de Chambord in particular. Long established as squires of large estates and rice paddies in the Camargue, the Forestas often welcomed Charles and his siblings there while they were growing up.


title: Charles, Prince Napoléon

text: Charles was born in Boulogne-Billancourt, France, along with his twin sister, Princess Catherine. He was baptised at "Saint-Louis-des-Invalides" by the Apostolic nuncio to France Archbishop Angelo Roncalli (later Pope John XXIII). Charles spent much of his youth at the family's ancestral retreat-in-exile, the "Villa Prangins" on Lake Geneva between Lausanne and Geneva in Switzerland. He has two younger siblings, Princess Laure (born 1952) and Prince Jérôme (born 1957). His sisters are married but the French imperial line of succession never descended to or through women, while his brother married at the age of 56 and has no issue.


title: Charles, Prince Napoléon

text: Charles attended school at "Sainte-croix-des-neiges" in Abondance, Haute-Savoie, taking off 1964–1965 to study German in the Black Forest. He holds a doctorate in economics from the Sorbonne. He has written essays and books, including "History of Urban Transportation" ("Histoire des Transports Urbains", Dunod-Bordas), "Bonaparte and Paoli" ("Bonaparte et Paoli", Plon-Perrin, 2000), "The Bonapartes, Rebels at Heart" ("Les Bonaparte, des esprits rebelles", Plon-Perrin, 2006), and "For a New Republic" ("Pour une nouvelle République", to be published by Pharos, 2007). He makes frequent public appearances in support of his political beliefs and candidacies.


title: Charles, Prince Napoléon

text: Charles has worked professionally as a banker, financial planner, and real estate developer and as a visiting professor at the American Institute on Foreign Policy.


title: Charles, Prince Napoléon

text: On 19 December 1978, Charles married his distant cousin, Princess Béatrice of Bourbon-Two Sicilies, daughter of Prince Ferdinand, Duke of Castro, a pretender to the throne of the Two Sicilies.


title: Charles, Prince Napoléon

text: On 28 September 1996, Charles was married in a civil ceremony to Jeanne-Françoise Valliccioni (born in Ortiporio, Corsica on 26 March 1958). She had previously married Erik Langrais on 15 July 1978 at Casaglione, Corsica, from whom she was divorced on 24 July 1990. When Charles and Jeanne-Françoise wed, they already had a daughter:


title: Charles, Prince Napoléon

text: Although officially recognized as heir apparent to the Bonapartist claim during the lifetime of his father Prince Louis Napoléon, when the latter's will was made public on 2 December 1997 (seven months after his death), it declared that Prince Charles was to be bypassed as dynastic heir in favour of his only son, Prince Jean-Christophe Napoléon, then 11 years old.


title: Charles, Prince Napoléon

text: In an interview published by "Le Figaro" on 2 December 1997, Jean-Marc Varaut, the attorney who witnessed the late Prince Louis Napoléon's will and subsequently represented the dynastic interests of Prince Jean Christophe against his father, stated that Prince Charles had alienated himself from the Bonaparte legacy by publicly espousing "republican and democratic opinions... He has deprived himself of all rights to dynastic heritage in remarrying without his father's permission... which is against the rules of the imperial family."


title: Charles, Prince Napoléon

text: Charles has expressed skepticism that his father's genuine intention was to disinherit him dynastically, "Without doubt, he had a mood swing, exploited by conservative elements in his entourage with whom I have long clashed... I am fighting so that my family ceases to be the victim of attempted manipulation." Moreover, Prince Charles denies that his father had the authority, by law or tradition, to exclude him from the order of succession: "Even if I accept their premise, referring me to the Senatus Consultus of Napoleon III, divorce did not exist under the Second Empire, so it cannot be taken into account for the succession... Moreover, the hypocrisy of this argument is exposed by the dates: My father's will was written in May 1996. I only re-married in October. All that matters is the Bonaparte tradition, which makes the eldest son the natural heir of his father."


title: Charles, Prince Napoléon

text: Aside from his second marriage, Varaut alleged that Louis was offended that his son unilaterally had French civil authorities change their surname from "Napoléon-Bonaparte" to "Napoléon" during his divorce in 1989. But Charles maintains that the family's legal surname had, in fact, been "Napoléon" until altered through clerical error on his birth certificate. When Charles requested that his surname be corrected, the civil authorities proceeded to apply the same change to the father's surname, "but not at my initiative."


title: Charles, Prince Napoléon

text: Varaut further drew attention to the fact that Charles was warned in advance by his father that he would be purged from the succession, and that he had responded to his father with a letter dated 16 June 1996 in which he asserted that his "republican" beliefs had already alienated him from the principles of the Imperial position, even before his father's decision to exclude him.


title: Charles, Prince Napoléon

text: When queried by the French royalty magazine, "Point de Vue", as to why he claimed headship of the Imperial dynasty in view of his republican pretensions, Charles replied, "I assume the 'moral heritage' of my name. To renounce today to my ability to become the head of our House would imply that I accept a certain number of grievances of which I have been accused...I cannot accept this sentence from another era. As for my republican sentiments, those who reproach me misunderstand the history of our family. Bonaparte – General, then First Consul – defended the Republic."


title: Charles, Prince Napoléon

text: In fact, the former heads of the House of Bonaparte, Napoleon I and his nephew Napoleon III, had been Republican leaders, respectively, First Consul of France and President of the French Republic, before they proclaimed themselves monarchs.


title: Charles, Prince Napoléon

text: Charles and his son have not engaged in the public feuding for which some of the past Bonaparte pretenders and their heirs have been notorious, and the father has stated of his son that "there will never be conflict between us". A pre-screening of "Un nom en héritage", a documentary television series on France's former dynasties, was the subject of a two-page spread in a December 2006 issue of "Point de Vue" that pictured Charles side by side with Jean-Christophe, both shown as participating in a cordial meeting between Napoleonic and Orléanist pretenders.


title: Charles, Prince Napoléon

text: Nonetheless, in November 2004 an issue of "Point de Vue" had announced that henceforth the magazine would accord the Bonapartist "title of pretence", "the Prince Napoleon", to Jean-Christophe, whereas since 1997 that title had been attributed to Charles. This decision followed receipt by the magazine of a protest from Jean-Marc Varaut, prompted by publication in an earlier issue of a reference to Charles as "head of the Imperial house". "Point de Vue", which sometimes gazettes monarchist announcements, published Varaut's re-assertion of the dynastic exclusion of Charles along with the prince's response: "...the title of 'head of family' among the Bonapartes devolves, at the death of the father, upon his eldest son. That rule is not susceptible to modification by the titleholder, "a fortiori" when the motives involved are petty and contrary to the Civil Code. I have the honour of bearing this charge since the death of my father, and my son will assume it in turn upon my death."


title: Charles, Prince Napoléon

text: In 2001, Charles moved to Corsica to run in Ajaccio's municipal elections. He joined a left-wing coalition which won an upset victory, and served as second deputy mayor, being responsible for the city's tourism industry.


title: Charles, Prince Napoléon

text: In early 2008, Charles announced plans to stand for election in March 2008 as mayor of Nemours, where he led a union list called "Ensemble Pour Les Nemouriens" with local personalities, such as Ginette Tardy. In the election, he was defeated by Valérie Lacroute.


title: Bajaj Group

text: Bajaj Group is an Indian multinational conglomerate founded by Jamnalal Bajaj in Mumbai in 1926. The group comprises 40 companies and its flagship company Bajaj Auto is ranked as the world's fourth largest two- and three-wheeler manufacturer. Other notable group companies include Bajaj Consumer Care, Bajaj Finance, Bajaj Finserv, Bajaj Energy, Bajaj Electricals, Bajaj Ventures, Bajaj Hindusthan, Bajaj Healthcare, Mukand, and Bajaj Holdings & Investment. The group has involvement in various industries that include automobiles (2- and 3-wheelers), home appliances, lighting, iron and steel, insurance, travel and finance.


title: Bajaj Group

text: Kamalnayan Bajaj, the elder son of Jamanalal Bajaj, after completing his education from University of Cambridge, England to assist his father both in business and in social service. He expanded the business by branching into manufacture of scooter, three-wheeler, cement, alloy casting and electricals. In 1954, Kamalnayan took over active management of the Bajaj Group companies.


title: Bajaj Group

text: Ramkrishna Bajaj, the younger son of Jamanalal, took over after the death of his elder brother Kamalnayan Bajaj in 1972. In addition to shouldering business responsibilities, Ramkrishna's energies were largely directed towards the social service and social welfare programmes of the Bajaj Group. He was elected as the Chairman of World Assembly for Youth (India) in 1961. He also held the office of the Managing Trustee of the Indian Youth Centres Trust, which conceived and created the Vishwa Yuvak Kendra in 1968, a youth development organisation.


title: Bajaj Group

text: Rahul Bajaj, the chairman emeritus and former managing director (until 2005) of the Bajaj group was the grandson of Jamnalal Bajaj. He completed his schooling from Cathedral, a school in Bombay. Then he pursued his studies from St Stephen's College, Delhi, Government Law College, Mumbai and Harvard University, USA. He took over control of the Bajaj Group in 1965 and established one of India's largest conglomerates. The President of India, presented CII President's Award for Lifetime Achievement to Mr. Rahul Bajaj on 27 April 2017.


title: Bajaj Group

text: Shiksha Mandal Wardha was established in 1914 by Jamnalal Bajaj for educating the youth of India. This Mandal was a part of the national movement and received support from several national leaders including Mohandas Karamchand Gandhi. It was also the first institute in India to prepare text books and conduct examinations in Hindi and Marathi at the graduate level. Currently, the Mandal runs two commerce colleges (in Wardha and Nagpur), a Science College and Agricultural College and Rural Institute and a Polytechnic at Wardha and in 2017 started its first engineering institution Bajaj institute of technology, Wardha (http://bit.shikshamandal.org/). It has almost 10,000 students on its rolls. Its Science College has been adjudged as a College with Potential for Excellence by the UGC. Its Agriculture College has been rated as 'A' by its affiliating university and its Polytechnic has been rated as excellent by MSBTE.


title: Bajaj Group

text: Kamalnayan Bajaj School location at Chinchwad was established in 1976. Initially, it started off as a school providing education from Lower KG to grade 12 and in 2007 it also started running a junior college.


title: Bajaj Group

text: Dnyaneshwar Vidyapeeth was supported by Madhur Bajaj, Vice-Chairman, Bajaj Auto Ltd for its autonomous engineering school which offers a variety of engineering professional courses.


title: Bajaj Group

text: Janaki Devi Bajaj Institute of Management Studies was established in August 1997. It is a Centre of Management Studies and the Postgraduate Department of Management Education of the SNDT Women's University. It offers a variety of full-time and part-time professional courses at Masters level and postgraduate diploma courses in management specifically for women.


title: Bajaj Group

text: Jamnalal Bajaj Institute of Management Studies, set up by the University of Mumbai in collaboration with the Graduate School of Business, Stanford University. With a donation from the Jamnalal Bajaj Seva Trust, was established in 1965. It was the first to start a full-time 2-year Masters Programme in Management Studies (MMS) in India. .


title: Bajaj Group

text: Bajaj Group volunteered to adopt 3 Industrial training institutes for Upgradation – ITI Mulshi, ITI Haveli and ITI Ramnager. A two-day training program was organised for all the staff of the Institutes, at a remote location


title: Bajaj Group

text: The company enabled education of eligible bright backward students with the launch of a program that would help scheduled castes and scheduled tribes students achieve academic excellence and make them at par with those who can afford coaching for top institutes.


title: Bajaj Group

text: Kamalnayan Bajaj Hospital in Aurangabad was established in 1990 as a hospital and research center. Although it was relatively small when it started, it has soon grown into a very well equipped hospital with 225 beds, 60 full-time doctors and 150 staff, organ transplant center, well-equipped Cath Lab, CT Scan, MRI, Mammography & Dept. of radiation oncology and so on.


title: Bajaj Group

text: The Bajaj-YCM Hospital A.R.T Center for HIV/Aids in Pimpri was established as a Public-Private Partnership between Government of India – Ministry of Health and Family Welfare – National AIDS Control Organisation (NACO) and Confederation of Indian Industry (CII) to provide healthcare facilities to Aids patients.


title: Bajaj Group

text: The objective of the Jankidevi Bajaj Gram Vikas Sanstha is to empower women and it has been doing so by training women in using improved technology for storage of food grains and initiating goat rearing projects owned and managed by women, emphasising the importance of family planning particularly tubectomy operations and securing loans for women members for both consumption and income generation.


title: Bajaj Group

text: IMC Ladies' Wing Jankidevi Bajaj Puraskar for Rural Entrepreneurship, which commemorates the birth centenary of the late Smt. Jankidevi Bajaj, is an award conferred for outstanding contribution of women working for rural development


title: Bajaj Group

text: The Jamnalal Bajaj Seva Trust initially assisted Sarvodaya workers and Gandhian constructive programmes. It later established the International Sarvodaya Centre in Vishwaneedam to promote agriculture, dairy development, rural development and training local women and youth for self-employment. It also funded the Jamnalar Bajaj Institute of Management Studies and undertook the maintenance of Bajajwadi at Wardha. It also has supported the Kamalnayan Bajaj Hall and Art Gallery.


title: Bajaj Group

text: The Jankidevi Bajaj Gram Vikas Sanstha and it helps the rural population develop self-reliance to do so by building family-size biogas plants, training women in using improved technology for storage of food grains and so on.


title: Bajaj Group

text: The IMC Ramkrishna Bajaj National Quality Awards were instituted in 1997 to encourage Indian Industry to be alert to the importance of quality in the context of global competitiveness. The Quality Award is presented every year to companies in manufacturing, service sector and small business company.


title: Bajaj Group

text: The Institute of Gandhian Studies, established in 1987, promotes long-term and short-term study courses on Gandhian thoughts and methodology. It organises seminars, consultative meets for Panchayat workers, special courses for women members of the Panchayats and trade union workers.


title: Bajaj Group

text: The trusts that work towards rural development include Jankidevi Bajaj Gram Vikas Sanstha, Jamnalal Bajaj Foundation, Jamnalal Kaniram Bajaj Trust and Jamnalal Bajaj Seva Trust. The welfare activities are carried out in collaboration with CAPART, Khadi and Village Industries Commission, NEDA, respective State Governments and beneficiaries. They are aimed at improving the living conditions of the rural population via income generation, training for self-employment, improved health and sanitation, supply of drinking water, improved agricultural and land maintenance practices such as horticulture, social forestry and reclamation of waste land. Other activities include distribution of solar-lantern and solar cookers, installation of biogas plants, deepening and widening of wells and drinking water scheme, tree plantation and kitchen gardens, lift irrigation, veterinary services like insemination, vaccination and distribution of cattle feed, watershed development and building of model villages, distribution of agricultural equipment and building a center of Child Labor Welfare.


title: Bajaj Group

text: In addition, the Bajaj Group has also undertaken several educational activities. They not only focus on mainstream education through the maintenance and running of Bal Sanskar Kendras, Balwadis and conducting study tours, but also on vocational education through tailoring classes, literacy and hobby classes, training programmes for self-employment, and so on. Jamnalal Bajaj Award was established in 1978 by the Jamnalal Bajaj Foundation.


title: Bajaj Group

text: The Jankidevi Bajaj Gram Vikas Sanstha has engaged in water conservation projects for improving agricultural productivity, helping build family-size biogas plants, conducting vermiculture projects, and so on.


title: Bajaj Group

text: Standing on the 12th position, it is one of the few Indian brands with an 'international' distinction, and that of being the largest producer of scooters in the world. In the Brand Trust Report 2012, Bajaj was ranked 7th Most Trusted brand in India and in Brand Trust Report 2013 Bajaj slipped one place to the 8th position among India's Most Trusted brands.


title: Bajaj Group

text: In 2014, Bajaj was ranked 46th among India's most trusted brands by the Brand Trust Report 2014. The Report also listed Bajaj Pulsar, Bajaj Allianz, Bajaj Electricals and Bajaj Almond Oil among India's most trusted brands.


title: Raju Srivastav

text: Satya Prakash Srivastav (25 December 1963 – 21 September 2022), known professionally as Raju Srivastav and often credited as Gajodhar, was an Indian comedian, actor and politician. He had been a member of the Bharatiya Janata Party since 2014.


title: Raju Srivastav

text: He was born in Kanpur, Uttar Pradesh, and moved to Mumbai in the 1980s to work in the Hindi film industry. He acted in "Baazigar", "Bombay to Goa", "Aamdani Atthanni Kharcha Rupaiya" among others. He contested in the comedy show "The Great Indian Laughter Challenge" and became the runner-up. He won the title of "The King of Comedy" in its spin-off show "The Great Indian Laughter Challenge – Champions". He did many stand-up comedy live shows.


title: Raju Srivastav

text: He was born in 1963 in Kanpur city in the state of Uttar Pradesh in a Kayastha family. His father Ramesh Srivastav was a poet. In his childhood, Srivastav liked to mimic film stars including Amitabh Bachchan.


title: Raju Srivastav

text: In 1980s he moved to Mumbai, and started his career by doing small roles in Bollywood films. He had a part in the Rajshri Productions movie "Maine Pyar Kiya" and other small roles in various movies such as "Baazigar" and "Bombay to Goa". He worked as an actor and comedian in the Bollywood movie "Aamdani Atthanni Kharcha Rupaiya".


title: Raju Srivastav

text: In 2005, ventured into stand-up comedy with the talent show "The Great Indian Laughter Challenge" and finished as second runner-up. Then he took part in its spin-off, "The Great Indian Laughter Challenge – Champions", and won the title of "The King of Comedy". He became famous with this show. By 2009, he had done more than 2,800 live shows.


title: Raju Srivastav

text: In 2009, in an interview, he said the vulgarity in comedy shows was a concern for him. He believed that comedians should practice self-regulation. Srivastav participated in "Bigg Boss (Hindi season 3)", the Indian counterpart of the "Big Brother (franchise)". After staying in the house for more than two months he was voted out on 4 December 2009. In 2010, Srivastav received threatening calls from Pakistan warning him not to crack jokes on underworld don Dawood Ibrahim and Pakistan during his shows.


title: Raju Srivastav

text: In 2013, Raju along with his wife participated in "Nach Baliye season 6", which is a couples dance show on StarPlus. He has also appeared on "Comedy Nights with Kapil".


title: Raju Srivastav

text: The Samajwadi Party (SP) fielded Srivastava from Kanpur Lok Sabha constituency for the 2014 Lok Sabha election. But on 11 March 2014, Srivastav returned the ticket, saying he was not getting enough support from the local units of the party. SP was expecting him to quit as the contest in the seat had become important. SP withdrew his candidature from Kanpur after he quit.


title: Raju Srivastav

text: Within days of leaving SP, he joined the Bharatiya Janata Party (BJP) on 19 March 2014. BJP did not give him the ticket for Lok Sabha 2014. He campaigned in support of BJP candidates in Lok Sabha and Assembly elections. In 2014, he was appointed by the BJP led Union government as the brand ambassador of the Swachh Bharat Abhiyan and had recorded advertisements for the campaign. In 2018, Srivastav disclosed on social media that he would get the chance to contest in the 2019 Indian general election as BJP candidate for Lok Sabha, although that did not materialize.


title: Raju Srivastav

text: In March 2019, he was appointed by the BJP-led Government of Uttar Pradesh as the chairman of the Uttar Pradesh Film Development Council.


title: Raju Srivastav

text: Widely described as the "king of comedy", his looks were also noted for having resembled Amitabh Bachchan.


title: Raju Srivastav

text: In January 2021, Raju Srivastav released a small video clip on social media criticizing the creators and actors of the web series "Tandav" for allegedly hurting Hindu sentiments by insulting Hindu religion and Hindu deities. In response, filmmaker Vinod Kapri and others shared several videos of Srivastav's comedy shows where he had used Hindu deities and the Indian holy epic Ramayana in his comedy sketches. Kapri said that Srivastav had mocked Hindu god Brahma and had joked about Brahma meeting actor Madhuri Dixit and that Brahma's white beard would turn red.


title: Raju Srivastav

text: Following Shrivastav's death, comedian Sunil Pal praised Shrivastav and added that "He would help juniors find gigs. He would also help his juniors financially, made sure they are paid on time and paid well. He brought in a lot of good changes in the comedy circle". Comedian Bharti Singh said that Shrivastav's death is "a great loss for the entire country".


title: Raju Srivastav

text: On 10 August 2022, while running on the treadmill in the gym, Raju Srivastav complained of chest pain and suffered a cardiac arrest. He underwent an angioplasty and was put on ventilator. Swelling was observed in his brain during his treatment and he was also treated by neurologists. His condition was stated to be critical ever since he suffered the heart attack. On the morning of 21 September 2022, he died during his treatment in Delhi.


title: Raju Srivastav

text: The post mortem was done using the method of virtual autopsy. His last rites were conducted in Delhi.


title: Raju Srivastav

text: Prolific figures including Narendra Modi, Yogi Adityanath, Rajnath Singh, Amit Shah, Ajay Devgn, Akshay Kumar, Anil Kapoor, Vivek Agnihotri, Rajpal Yadav and others expressed their condolences over Shrivastav's death.


title: Saber-toothed predator

text: A saber-tooth (alternatively spelled sabre-tooth) is any member of various extinct groups of predatory therapsids, predominantly carnivoran mammals, that are characterized by long, curved saber-shaped canine teeth which protruded from the mouth when closed. Saber-toothed mammals have been found almost worldwide from the Eocene epoch to the end of the Pleistocene epoch 42 million years ago (mya) – 11,000 years ago (kya).


title: Saber-toothed predator

text: One of the best-known genera is the machairodont or "saber-toothed cat" "Smilodon", the species of which, especially "S. fatalis", are popularly referred to as "saber-toothed tigers", although they are not closely related to tigers ("Panthera"). Despite some similarities, not all saber-tooths are closely related to saber-toothed cats or felids in-general. Instead, many members are classified into different families of Feliformia, such as Barbourofelidae and Nimravidae; the oxyaenid "creodont" genera "Machaeroides" and "Apataelurus"; and two extinct lineages of metatherian mammals, the thylacosmilids of Sparassodonta, and deltatheroideans, which are more closely related to marsupials. In this regard, these saber-toothed mammals can be viewed as examples of convergent evolution. This convergence is remarkable due not only to the development of elongated canines, but also a suite of other characteristics, such as a wide gape and bulky forelimbs, which is so consistent that it has been termed the "saber-tooth suite."


title: Saber-toothed predator

text: Of the feliform lineages, the family Nimravidae is the oldest, entering the landscape around 42 mya and becoming extinct by 7.2 mya. Barbourofelidae entered around 16.9 mya and were extinct by 9 mya. These two would have shared some habitats.


title: Saber-toothed predator

text: The different groups of saber-toothed predators evolved their saber-toothed characteristics entirely independently. They are most known for having maxillary canines which extended down from the mouth when the mouth was closed. Saber-toothed cats were generally more robust than today's cats and were quite bear-like in build. They are believed to have been excellent hunters, taking animals such as sloths, mammoths, and other large prey. Evidence from the numbers found at the La Brea Tar Pits suggests that "Smilodon", like modern lions, was a social carnivore.


title: Saber-toothed predator

text: The first saber-tooths to appear were non-mammalian synapsids, such as the gorgonopsids; they were one of the first groups of animals within Synapsida to experience the specialization of saber teeth, and many had long canines. Some had two pairs of upper canines with two jutting down from each side, but most had one pair of upper extreme canines. Because of their primitiveness, they are extremely easy to tell from machairodonts. Several defining characteristics are a lack of a coronoid process, many sharp "premolars" more akin to pegs than scissors, and very long skulls. Despite their large canines, however, most gorgonopsians probably lacked the other specializations found in true saber-toothed predator ecomorphs. Two gorgonopsians, "Smilesaurus" and "Inostrancevia", had exceptionally large canines and may have been closer functional analogues to later sabertooths.


title: Saber-toothed predator

text: The second appearance is in Deltatheroida, a lineage of Cretaceous metatherians. At least one genus, "Lotheridium", possessed long canines, and given both the predatory habits of the clade as well as the generally incomplete material, this may have been a more widespread adaptation.


title: Saber-toothed predator

text: The third appearance of long canines is "Thylacosmilus", which is the most distinctive of the saber-tooth mammals and is also easy to tell apart. It differs from machairodonts in possessing a very prominent flange and a tooth that is triangular in cross section. The root of the canines is more prominent than in machairodonts and a true sagittal crest is absent.


title: Saber-toothed predator

text: The fourth instance of saber-teeth is from the clade Oxyaenidae. The small and slender "Machaeroides" bore canines that were thinner than in the average machairodont. Its muzzle was longer and narrower.


title: Saber-toothed predator

text: The fifth saber-tooth appearance is the ancient feliform (carnivoran) family Nimravidae. Both groups have short skulls with tall sagittal crests, and their general skull shape is very similar. Some have distinctive flanges, and some have none at all, so this confuses the matter further. Machairodonts were almost always bigger, though, and their canines were longer and more stout for the most part, but exceptions do appear.


title: Saber-toothed predator

text: The sixth appearance is the barbourofelids. These feliform carnivorans are very closely related to actual cats. The best-known barbourofelid is the eponymous "Barbourofelis", which differs from most machairodonts by having a much heavier and more stout mandible, smaller orbits, massive and almost knobby flanges, and canines that are farther back. The average machairodont had well-developed incisors, but barbourofelids' were more extreme.


title: Saber-toothed predator

text: The evolution of enlarged canines in Tertiary carnivores was a result of large mammals being the source of prey for saber-toothed predators. The development of the saber-toothed condition appears to represent a shift in function and killing behavior, rather than one in predator-prey relations. Many hypotheses exist concerning saber-tooth killing methods, some of which include attacking soft tissue such as the belly and throat, where biting deep was essential to generate killing blows. The elongated teeth also aided with strikes reaching major blood vessels in these large mammals. However, the precise functional advantage of the saber-tooth's bite, particularly in relation to prey size, is a mystery. A new point-to-point bite model is introduced in the article by Andersson et al., showing that for saber-tooth cats, the depth of the killing bite decreases dramatically with increasing prey size. The extended gape of saber-toothed cats results in a considerable increase in bite depth when biting into prey with a radius of less than 10 cm. For the saber-tooth, this size-reversed functional advantage suggests predation on species within a similar size range to those attacked by present-day carnivorans, rather than "megaherbivores" as previously believed.


title: Saber-toothed predator

text: A disputing view of the cat's hunting technique and ability is presented by C. K. Brain in "The Hunters or the Hunted?" in which he attributes the cat's prey-killing abilities to its large neck muscles rather than its jaws. Large cats use both the upper and lower jaw to bite down and bring down the prey. The strong bite of the jaw is accredited to the strong temporalis muscle that attach from the skull to the coronoid process of the jaw. The larger the coronoid process, the larger the muscle that attaches there, so the stronger the bite. As C.K. Brain points out, the saber-toothed cats had a greatly reduced coronoid process and therefore a disadvantageously weak bite. The cat did, however, have an enlarged mastoid process, a muscle attachment at the base of the skull, which attaches to neck muscles. According to C.K. Brain, the saber-tooth would use a "downward thrust of the head, powered by the neck muscles" to drive the large upper canines into the prey. This technique was "more efficient than those of true cats".


title: Saber-toothed predator

text: The similarity in all these unrelated families involves the convergent evolution of the saber-like canines as a hunting adaptation. Meehan "et al." note that it took around 8 million years for a new type of saber-toothed cat to fill the niche of an extinct predecessor in a similar ecological role; this has happened at least four times with different families of animals developing this adaptation. Although the adaptation of the saber-like canines made these creatures successful, it seems that the shift to obligate carnivorism, along with co-evolution with large prey animals, led the saber-toothed cats of each time period to extinction. As per Van Valkenburgh, the adaptations that made saber-toothed cats successful also made the creatures vulnerable to extinction. In her example, trends toward an increase in size, along with greater specialization, acted as a "macro-evolutionary ratchet": when large prey became scarce or extinct, these creatures would be unable to adapt to smaller prey or consume other sources of food, and would be unable to reduce their size so as to need less food.


title: Saber-toothed predator

text: More recently, it has been suggested that "Thylacosmilus" differed radically from its placental counterparts in possessing differently shaped canines and lacking incisors. This suggests that it was not ecologically analogous to other saber-teeth and possibly an entrail specialist. Another study has found that other saber toothed species similarly had diverse lifestyles and that superficial anatomical similarities obscure them.


title: Apollo Guidance Computer

text: The Apollo Guidance Computer (AGC) was a digital computer produced for the Apollo program that was installed on board each Apollo command module (CM) and Apollo Lunar Module (LM). The AGC provided computation and electronic interfaces for guidance, navigation, and control of the spacecraft. The AGC was the first computer based on silicon integrated circuits. The computer's performance was comparable to the first generation of home computers from the late 1970s, such as the Apple II, TRS-80, and Commodore PET.


title: Apollo Guidance Computer

text: The AGC has a 16-bit word length, with 15 data bits and one parity bit. Most of the software on the AGC is stored in a special read-only memory known as core rope memory, fashioned by weaving wires through and around magnetic cores, though a small amount of read/write core memory is available.


title: Apollo Guidance Computer

text: Astronauts communicated with the AGC using a numeric display and keyboard called the DSKY (for "display and keyboard", pronounced "DIS-kee"). The AGC and its DSKY user interface were developed in the early 1960s for the Apollo program by the MIT Instrumentation Laboratory and first flew in 1966.


title: Apollo Guidance Computer

text: Astronauts manually flew Project Gemini with control sticks, but computers flew most of Project Apollo except briefly during lunar landings. Each Moon flight carried two AGCs, one each in the command module and the Apollo Lunar Module, with the exception of Apollo 8 which did not need a lunar module for its lunar orbit mission. The AGC in the command module was the center of its guidance, navigation and control (GNC) system. The AGC in the lunar module ran its Apollo PGNCS (primary guidance, navigation and control system), with the acronym pronounced as "pings".


title: Apollo Guidance Computer

text: The AGC was designed at the MIT Instrumentation Laboratory under Charles Stark Draper, with hardware design led by Eldon C. Hall. Early architectural work came from J. H. Laning Jr., Albert Hopkins, Richard Battin, Ramon Alonso,


title: Apollo Guidance Computer

text: The flight hardware was fabricated by Raytheon, whose Herb Thaler was also on the architectural team.


title: Apollo Guidance Computer

text: Following the use of integrated circuit (IC) chips in the Interplanetary Monitoring Platform (IMP) in 1963, IC technology was later adopted for the AGC. The Apollo flight computer was the first computer to use silicon IC chips.


title: Apollo Guidance Computer

text: While the Block I version used 4,100 ICs, each containing a single three-input NOR gate, the later Block II version (used in the crewed flights) used about 2,800 ICs, mostly dual three-input NOR gates and smaller numbers of expanders and sense amplifiers. The ICs, from Fairchild Semiconductor, were implemented using resistor–transistor logic (RTL) in a flat-pack. They were connected via wire wrap, and the wiring was then embedded in cast epoxy plastic.


title: Apollo Guidance Computer

text: The use of a single type of IC (the dual NOR3) throughout the AGC avoided problems that plagued another early IC computer design, the Minuteman II guidance computer, which used a mix of diode–transistor logic and diode logic gates. NOR gates are universal logic gates from which any other gate can be made, though at the cost of using more gates.


title: Apollo Guidance Computer

text: The computer had 2048 words of erasable magnetic-core memory and 36,864 words of read-only core rope memory. Both had cycle times of 11.72 microseconds. The memory word length was 16 bits: 15 bits of data and one odd-parity bit. The CPU-internal 16-bit word format was 14 bits of data, one overflow bit, and one sign bit (ones' complement representation).


title: Apollo Guidance Computer

text: The user interface to the AGC was the "DSKY", standing for "display and keyboard" and usually pronounced ""DIS-kee"." It has an array of indicator lights, numeric displays, and a calculator-style keyboard. Commands were entered numerically, as two-digit numbers: Verb, and Noun. "Verb" described the type of action to be performed and "Noun" specified which data were affected by the action specified by the Verb command.


title: Apollo Guidance Computer

text: Each digit was displayed via a green (specified as 530 nm) high-voltage electroluminescent seven-segment display; these were driven by electromechanical relays, limiting the update rate. Three five-digit signed numbers could also be displayed in octal or decimal, and were typically used to display vectors such as space craft attitude or a required velocity change (delta-V). Although data was stored internally in metric units, they were displayed as United States customary units. This calculator-style interface was the first of its kind.


title: Apollo Guidance Computer

text: The command module has two DSKYs connected to its AGC: one located on the main instrument panel and a second located in the lower equipment bay near a sextant used for aligning the inertial guidance platform. The lunar module had a single DSKY for its AGC. A flight director attitude indicator (FDAI), controlled by the AGC, was located above the DSKY on the commander's console and on the LM.


title: Apollo Guidance Computer

text: The AGC timing reference came from a 2.048 MHz crystal clock. The clock was divided by two to produce a four-phase 1.024 MHz clock which the AGC used to perform internal operations. The 1.024 MHz clock was also divided by two to produce a 512 kHz signal called the "master frequency"; this signal was used to synchronize external Apollo spacecraft systems.


title: Apollo Guidance Computer

text: The master frequency was further divided through a "scaler", first by five using a ring counter to produce a 102.4 kHz signal. This was then divided by two through 17 successive stages called F1 (51.2 kHz) through F17 (0.78125 Hz). The F10 stage (100 Hz) was fed back into the AGC to increment the real-time clock and other involuntary counters using Pinc (discussed below). The F17 stage was used to intermittently run the AGC when it was operating in the "standby" mode.


title: Apollo Guidance Computer

text: There were also four locations in core memory, at addresses 20–23, dubbed "editing locations" because whatever was stored there would emerge shifted or rotated by one bit position, except for one that shifted right seven bit positions, to extract one of the seven-bit interpretive op. codes that were packed two to a word. This was common to Block I and Block II AGCs.


title: Apollo Guidance Computer

text: The instruction format used 3 bits for opcode, and 12 bits for address. Block I had 11 instructions: codice_2, codice_5, codice_6, codice_7, codice_8, codice_9, codice_10, and codice_11 (basic), and codice_12, codice_3, and codice_1 (extra). The first eight, called "basic instructions", were directly accessed by the 3-bit op. code. The final three were denoted as "extracode instructions" because they were accessed by performing a special type of codice_2 instruction (called codice_16) immediately before the instruction.


title: Apollo Guidance Computer

text: Instructions were implemented in groups of 12 steps, called "timing pulses". The timing pulses were named TP1 through TP12. Each set of 12 timing pulses was called an instruction "subsequence". Simple instructions, such as TC, executed in a single subsequence of 12 pulses. More complex instructions required several subsequences. The multiply instruction (codice_3) used 8 subsequences: an initial one called codice_60, followed by an codice_61 subsequence which was repeated 6 times, and then terminated by an codice_62 subsequence. This was reduced to 3 subsequences in Block II.


title: Apollo Guidance Computer

text: Each timing pulse in a subsequence could trigger up to 5 "control pulses". The control pulses were the signals which did the actual work of the instruction, such as reading the contents of a register onto the bus, or writing data from the bus into a register.


title: Apollo Guidance Computer

text: Block I AGC memory was organized into 1 kiloword banks. The lowest bank (bank 0) was erasable memory (RAM). All banks above bank 0 were fixed memory (ROM). Each AGC instruction had a 12-bit address field. The lower bits (1-10) addressed the memory inside each bank. Bits 11 and 12 selected the bank: 00 selected the erasable memory bank; 01 selected the lowest bank (bank 1) of fixed memory; 10 selected the next one (bank 2); and 11 selected the "Bank" register that could be used to select any bank above 2. Banks 1 and 2 were called "fixed-fixed" memory, because they were always available, regardless of the contents of the Bank register. Banks 3 and above were called "fixed-switchable" because the selected bank was determined by the bank register.


title: Apollo Guidance Computer

text: The Block I AGC initially had 12 kilowords of fixed memory, but this was later increased to 24 kilowords. Block II had 36 kilowords of fixed memory and 2 kilowords of erasable memory.


title: Apollo Guidance Computer

text: The AGC transferred data to and from memory through the G register in a process called the "memory cycle". The memory cycle took 12 timing pulses (11.72 μs). The cycle began at timing pulse 1 (TP1) when the AGC loaded the memory address to be fetched into the S register. The memory hardware retrieved the data word from memory at the address specified by the S register. Words from erasable memory were deposited into the G register by timing pulse 6 (TP6); words from fixed memory were available by timing pulse 7. The retrieved memory word was then available in the G register for AGC access during timing pulses 7 through 10. After timing pulse 10, the data in the G register was written back to memory.


title: Apollo Guidance Computer

text: The AGC memory cycle occurred continuously during AGC operation. Instructions needing memory data had to access it during timing pulses 7–10. If the AGC changed the memory word in the G register, the changed word was written back to memory after timing pulse 10. In this way, data words cycled continuously from memory to the G register and then back again to memory.


title: Apollo Guidance Computer

text: The lower 15 bits of each memory word held AGC instructions or data, with each word being protected by a 16th odd parity bit. This bit was set to 1 or 0 by a parity generator circuit so a count of the 1s in each memory word would always produce an odd number. A parity checking circuit tested the parity bit during each memory cycle; if the bit didn't match the expected value, the memory word was assumed to be corrupted and a "parity alarm" panel light was illuminated.


title: Apollo Guidance Computer

text: The AGC responded to each interrupt by temporarily suspending the current program, executing a short interrupt service routine, and then resuming the interrupted program.


title: Apollo Guidance Computer

text: The AGC also had 20 involuntary counters. These were memory locations which functioned as up/down counters, or shift registers. The counters would increment, decrement, or shift in response to internal inputs. The increment ("Pinc"), decrement ("Minc"), or shift ("Shinc") was handled by one subsequence of microinstructions inserted between any two regular instructions.


title: Apollo Guidance Computer

text: Interrupts could be triggered when the counters overflowed. The T3rupt and Dsrupt interrupts were produced when their counters, driven by a 100 Hz hardware clock, overflowed after executing many Pinc subsequences. The Uprupt interrupt was triggered after its counter, executing the Shinc subsequence, had shifted 16 bits of uplink data into the AGC.


title: Apollo Guidance Computer

text: The AGC had a power-saving mode controlled by a "standby allowed" switch. This mode turned off the AGC power, except for the 2.048 MHz clock and the scaler. The F17 signal from the scaler turned the AGC power and the AGC back on at 1.28 second intervals. In this mode, the AGC performed essential functions, checked the standby allowed switch, and, if still enabled, turned off the power and went back to sleep until the next F17 signal.


title: Apollo Guidance Computer

text: In the standby mode, the AGC slept most of the time; therefore it was not awake to perform the Pinc instruction needed to update the AGC's real time clock at 10 ms intervals. To compensate, one of the functions performed by the AGC each time it awoke in the standby mode was to update the real time clock by 1.28 seconds.


title: Apollo Guidance Computer

text: The standby mode was designed to reduce power by 5 to 10 W (from 70 W) during midcourse flight when the AGC was not needed. However, in practice, the AGC was left on during all phases of the mission and this feature was never used.


title: Apollo Guidance Computer

text: The AGC had a 16-bit read bus and a 16-bit write bus. Data from central registers (A, Q, Z, or LP), or other internal registers could be gated onto the read bus with a control signal. The read bus connected to the write bus through a non-inverting buffer, so any data appearing on the read bus also appeared on the write bus. Other control signals could copy write bus data back into the registers.


title: Apollo Guidance Computer

text: Data transfers worked like this: To move the address of the next instruction from the B register to the S register, an RB (read B) control signal was issued; this caused the address to move from register B to the read bus, and then to the write bus. A WS (write S) control signal moved the address from the write bus into the S register.


title: Apollo Guidance Computer

text: Several registers could be read onto the read bus simultaneously. When this occurred, data from each register was inclusive-"OR"ed onto the bus. This inclusive-"OR" feature was used to implement the Mask instruction, which was a logical "AND" operation. Because the AGC had no native ability to do a logical "AND", but could do a logical "OR" through the bus and could complement (invert) data through the C register, De Morgan's theorem was used to implement the equivalent of a logical "AND". This was accomplished by inverting both operands, performing a logical "OR" through the bus, and then inverting the result.


title: Apollo Guidance Computer

text: AGC software was written in AGC assembly language and stored on rope memory. The bulk of the software was on read-only rope memory and thus could not be changed in operation, but some key parts of the software were stored in standard read-write magnetic-core memory and could be overwritten by the astronauts using the DSKY interface, as was done on Apollo 14.


title: Apollo Guidance Computer

text: A simple real-time operating system designed by J. Halcombe Laning consisting of the 'Exec', a batch job-scheduling using cooperative multi-tasking, and an interrupt-driven pre-emptive scheduler called the 'Waitlist' which scheduled timer-driven 'tasks', controlled the computer. Tasks were short threads of execution which could reschedule themselves for re-execution on the Waitlist, or could kick off a longer operation by starting a 'job' with the Exec. Calculations were carried out using the metric system, but display readouts were in units of feet, feet per second, and nautical miles – units that the Apollo astronauts were accustomed to.


title: Apollo Guidance Computer

text: The AGC had a sophisticated software interpreter, developed by the MIT Instrumentation Laboratory, that implemented a virtual machine with more complex and capable pseudo-instructions than the native AGC. These instructions simplified the navigational programs. Interpreted code, which featured double precision trigonometric, scalar and vector arithmetic (16 and 24-bit), even an codice_63 (matrix × vector) instruction, could be mixed with native AGC code. While the execution time of the pseudo-instructions was increased (due to the need to interpret these instructions at runtime) the interpreter provided many more instructions than AGC natively supported and the memory requirements were much lower than in the case of adding these instructions to the AGC native language which would require additional memory built into the computer (at that time the memory capacity was very expensive). The average pseudo-instruction required about 24 ms to execute. The assembler, named "YUL" for an early prototype "Christmas Computer", enforced proper transitions between native and interpreted code.


title: Apollo Guidance Computer

text: A set of interrupt-driven user interface routines called 'Pinball' provided keyboard and display services for the jobs and tasks running on the AGC. A set of user-accessible routines were provided to let the astronauts display the contents of various memory locations in octal or decimal in groups of 1, 2, or 3 registers at a time. 'Monitor' routines were provided so the operator could initiate a task to periodically redisplay the contents of certain memory locations. Jobs could be initiated.


title: Apollo Guidance Computer

text: The design principles developed for the AGC by MIT Instrumentation Laboratory, directed in late 1960s by Charles Draper, became foundational to software engineering—particularly for the design of more reliable systems that relied on asynchronous software, priority scheduling, testing, and human-in-the-loop decision capability. When the design requirements for the AGC were defined, necessary software and programming techniques did not exist so they had to be designed from scratch. Many of the trajectory and guidance algorithms used were based on earlier work by Richard Battin. The first command module flight was controlled by a software package called CORONA whose development was led by Alex Kosmala. Software for lunar missions consisted of COLOSSUS for the command module, whose development was led by Frederic Martin, and LUMINARY on the lunar module led by George Cherry. Details of these programs were implemented by a team under the direction of Margaret Hamilton. Hamilton was very interested in how the astronauts would interact with the software and predicted the types of errors that could occur due to human error. In total, software development on the project comprised 1400 person-years of effort, with a peak workforce of 350 people. In 2016, Hamilton received the Presidential Medal of Freedom for her role in creating the flight software.


title: Apollo Guidance Computer

text: The Apollo Guidance Computer software influenced the design of Skylab, Space Shuttle and early fly-by-wire fighter aircraft systems.


title: Apollo Guidance Computer

text: The Apollo Guidance computer has been called "The fourth astronaut" for its role in helping the three astronauts who relied on it Neil Armstrong, Buzz Aldrin and Michael Collins.


title: Apollo Guidance Computer

text: A Block II version of the AGC was designed in 1966. It retained the basic Block I architecture, but increased erasable memory from 1 to 2 kilowords. Fixed memory was expanded from 24 to 36 kilowords. Instructions were expanded from 11 to 34 and I/O channels were implemented to replace the I/O registers on Block I. The Block II version is the one that actually flew to the moon. Block I was used during the uncrewed Apollo 4 and 6 flights, and was on board the ill-fated Apollo 1.


title: Apollo Guidance Computer

text: The decision to expand the memory and instruction set for Block II, but to retain the Block I's restrictive three-bit op. code and 12-bit address had interesting design consequences. Various tricks were employed to squeeze in additional instructions, such as having special memory addresses which, when referenced, would implement a certain function. For instance, an codice_6 to address 25 triggered the codice_38 instruction to return from an interrupt. Likewise, codice_6 17 performed an codice_67 instruction (inhibit interrupts), while codice_6 16 reenabled them (codice_69). Other instructions were implemented by preceding them with a special version of codice_2 called codice_16. The address spaces were extended by employing the Bank (fixed) and Ebank (erasable) registers, so the only memory of either type that could be addressed at any given time was the current bank, plus the small amount of fixed-fixed memory and the erasable memory. In addition, the bank register could address a maximum of 32 kilowords, so an Sbank (super-bank) register was required to access the last 4 kilowords. All across-bank subroutine calls had to be initiated from fixed-fixed memory through special functions to restore the original bank during the return: essentially a system of far pointers.


title: Apollo Guidance Computer

text: The Block II AGC also has the codice_72 instruction (the name is a contraction of "Ed's Interrupt", after Ed Smally, the programmer who requested it). This instruction does not generate an interrupt, rather it performs two actions that are common to interrupt processing. The first action, inhibits further interrupts (and requires a codice_73 instruction to enable them again). In the second action, the codice_74 register is loaded with the current value of the program counter (Z). It was only used once in the Apollo software, for setting up the DAP cycle termination sequence in the Digital Autopilot of the lunar module. It is believed to be responsible for problems emulating the LEM AGC Luminary software.


title: Apollo Guidance Computer

text: PGNCS generated unanticipated warnings during Apollo 11's lunar descent, with the AGC showing a "1202 alarm" ("Executive overflow - NO CORE SETS"), and then a "1201 alarm" ("Executive overflow - NO VAC AREAS"). The response of the AGC to either alarm was a soft restart. The cause was a rapid, steady stream of spurious cycle steals from the rendezvous radar (tracking the orbiting command module), intentionally left on standby during the descent in case it was needed for an abort.


title: Apollo Guidance Computer

text: During this part of the approach, the processor would normally be almost 85% loaded. The extra 6,400 cycle steals per second added the equivalent of 13% load, leaving just enough time for all scheduled tasks to run to completion. Five minutes into the descent, Buzz Aldrin gave the computer the command "1668", which instructed it to periodically calculate and display DELTAH (the difference between altitude sensed by the radar and the computed altitude). The "1668" added another 10% to the processor workload, causing executive overflow and a "1202" alarm. After being given the "GO" from Houston, Aldrin entered "1668" again and another "1202" alarm occurred. When reporting the second alarm, Aldrin added the comment "It appears to come up when we have a "1668" up". The AGC software had been designed with priority scheduling, and automatically recovered, deleting lower priority tasks including the "1668" display task, to complete its critical guidance and control tasks. Guidance controller Steve Bales and his support team that included Jack Garman issued several "GO" calls and the landing was successful. For his role, Bales received the US Presidential Medal of Freedom on behalf of the entire control center team and the three Apollo astronauts.


title: Apollo Guidance Computer

text: The problem was not a programming error in the AGC, nor was it pilot error. It was a peripheral hardware design bug that had already been known and documented by Apollo 5 engineers. However, because the problem had only occurred once during testing, they concluded that it was safer to fly with the existing hardware that they had already tested, than to fly with a newer but largely untested radar system. In the actual hardware, the position of the rendezvous radar was encoded with synchros excited by a different source of 800 Hz AC than the one used by the computer as a timing reference. The two 800 Hz sources were frequency locked but not phase locked, and the small random phase variations made it appear as though the antenna was rapidly "dithering" in position, even though it was completely stationary. These phantom movements generated the rapid series of cycle steals.


title: Apollo Guidance Computer

text: J. Halcombe Laning's software and computer design saved the Apollo 11 landing mission. Had it not been for Laning's design, the landing would have been aborted for lack of a stable guidance computer.


title: Apollo Guidance Computer

text: The AGC formed the basis of an experimental fly-by-wire (FBW) system installed into an F-8 Crusader to demonstrate the practicality of computer driven FBW. The AGC used in the first phase of the program was replaced with another machine in the second phase, and research done on the program led to the development of fly-by-wire systems for the Space Shuttle. The AGC also led, albeit indirectly, to the development of fly-by-wire systems for the generation of fighters that were being developed at the time.


title: Apollo Guidance Computer

text: In 2003, an effort was started by Ron Burkey to recover the source code that powered the AGC and build an emulator able to run it, the VirtualAGC. Part of the large amount of source code rescued as a result of this effort was uploaded by a former NASA intern to GitHub on July 7, 2016, attracting significant media attention. The original Apollo 11 Guidance Computer source code was originally made accessible in 2003 by the Virtual AGC Project and MIT Museum. It was transcribed and digitalized from the original hard-copy source code listings that were made in the 60s. In mid 2016, former NASA intern, Chris Garry, uploaded the AGC Source code onto GitHub.


title: Zlib

text: zlib ( or "zeta-lib", ) is a software library used for data compression. zlib was written by Jean-loup Gailly and Mark Adler and is an abstraction of the DEFLATE compression algorithm used in their gzip file compression program. zlib is also a crucial component of many software platforms, including Linux, macOS, and iOS. It has also been used in gaming consoles such as the PlayStation 4, PlayStation 3, Wii U, Wii, Xbox One and Xbox 360.


title: Zlib

text: The first public version of zlib, 0.9, was released on 1 May 1995 and was originally intended for use with the libpng image library. It is free software, distributed under the zlib License.


title: Zlib

text: zlib compressed data are typically written with a gzip or a zlib wrapper. The wrapper encapsulates the raw DEFLATE data by adding a header and trailer. This provides stream identification and error detection that are not provided by the raw DEFLATE data.


title: Zlib

text: The gzip header, used in the ubiquitous gzip file format, is larger than the zlib header, as it stores a file name and other file system information.


title: Zlib

text: , zlib only supports one algorithm, called DEFLATE, which uses a combination of a variation of LZ77 (Lempel–Ziv 1977) and Huffman coding. This algorithm provides good compression on a wide variety of data with minimal use of system resources. This is also the algorithm used in the Zip archive format. The header makes allowance for other algorithms, but none are currently implemented.


title: Zlib

text: zlib provides facilities for control of processor and memory use. A compression level value may be supplied that trades speed for compression. There are also facilities for conserving memory, useful in restricted memory environments, such as some embedded systems.


title: Zlib

text: The compression can be optimized for specific types of data. If one is using the library to always compress specific types of data, then using a specific strategy may improve compression and performance. For example, if the data contain long lengths of repeated bytes, the run-length encoding (RLE) strategy may give good results at a higher speed. For general data, the default strategy is preferred.


title: Zlib

text: Errors in compressed data may be detected and skipped. Further, if "full-flush" points are written to the compressed stream, then corrupt data can be skipped, and the decompression will resynchronize at the next flush point — although no error recovery of the corrupt data is provided. Full-flush points are useful for large data streams on unreliable channels, where some data loss is unimportant, such as in some multimedia applications. However, creating many flush points can affect the speed as well as the amount (ratio) of compression.


title: Zlib

text: There is no limit to the length of data that can be compressed or decompressed. Repeated calls to the library allow an unlimited number of blocks of data to be handled. Some ancillary code (counters) may suffer from overflow for long data streams, but this does not affect the actual compression or decompression.


title: Zlib

text: When compressing a long (or infinite) data stream, it is advisable to write regular full-flush points.


title: Zlib

text: Today, zlib is something of a "de facto" standard, to the point that zlib and DEFLATE are often used interchangeably in standards documents, with thousands of applications relying on it for compression, either directly or indirectly. These include:


title: Zlib

text: zlib is also used in many embedded devices, such as the Apple iPhone and Sony PlayStation 3, because the code is portable, liberally licensed, and has a relatively small memory footprint.


title: Zlib

text: A commonly used library built on an old codebase, zlib is also frequently forked by third-parties that claim improvements to this library:


title: Monarchies of Malaysia

text: The monarchies of Malaysia refer to the constitutional monarchy system as practised in Malaysia. The political system of Malaysia is based on the Westminster parliamentary system in combination with features of a federation.


title: Monarchies of Malaysia

text: Nine of the states of Malaysia are constitutionally headed by traditional Malay rulers, collectively referred to as the Malay states. State constitutions limit eligibility for the thrones to male Malay Muslims of royal descent. Seven are hereditary monarchies based on agnatic primogeniture: Kedah, Kelantan, Johor, Perlis, Pahang, Selangor and Terengganu. In Perak, the throne rotates among three branches of the royal family loosely based on agnatic seniority. One state, Negeri Sembilan, is an elective monarchy; the ruler is elected from male members of the royal family by hereditary chiefs. All rulers, except those of Perlis and of Negeri Sembilan, use the title of "Sultan". The ruler of Perlis is styled the "Raja", whereas the ruler of Negeri Sembilan is known as the "Yang di-Pertuan Besar".


title: Monarchies of Malaysia

text: Every five years or when a vacancy occurs, the rulers convene as the Conference of Rulers () to elect among themselves the Yang di-Pertuan Agong, the federal constitutional monarch and head of state of Malaysia. As the Yang di-Pertuan Agong is elected among the rulers, Malaysia, as a whole, is also an elective monarchy.


title: Monarchies of Malaysia

text: Each of the nine rulers serves as the head of state of his own state, as well as the head of the religion of Islam in his state. As with other constitutional monarchs around the world, the rulers do not participate in the actual governance in their states; instead, each of them is bound by convention to act on the advice of the head of government of his state, known as Menteri Besar (pl. Menteri-menteri Besar). However, the ruler of each state has discretionary powers in appointing the Menteri Besar that commands a majority in the state legislative assembly, and refusing a dissolution of the state assembly when requested by the Menteri Besar. The powers of the monarchs have been restricted over time, although there is debate about the precise limits of their powers.


title: Monarchies of Malaysia

text: The Yang di-Pertuan Agong is the federal head of state. His symbolic roles include being the Commander-in-Chief of the Malaysian Armed Forces, and carrying out diplomatic functions such as receiving foreign diplomats and representing Malaysia on state visits. The Yang di-Pertuan Agong is the head of Islam in his own state, the four states without rulers (Penang, Malacca, Sabah and Sarawak) and the Federal Territories. The Yang di-Pertuan Agong is required to delegate all his state powers to a regent, except for the role of head of Islam. Similar to other rulers, the Yang di-Pertuan Agong acts on the advice of the Prime Minister, and has discretionary powers in appointing the Prime Minister that commands a majority in the Dewan Rakyat, the lower house of the Parliament, and refusing a dissolution of the Parliament. The Yang di-Pertuan Agong also appoints the Yang di-Pertua Negeri, the ceremonial governors for the four states without rulers, on the advice of the Prime Minister and the Chief Ministers of the states.


title: Monarchies of Malaysia

text: A unique feature of the constitutional monarchy in Malaysia is the Conference of Rulers, consisting of the nine rulers and the four Yang di-Pertua Negeris. The Conference convenes triannually to discuss various issues related to state and national policies. The most important role of the Conference is to elect the Yang di-Pertuan Agong every five years or when a vacancy occurs. Only the rulers participate in the election of the Yang di-Pertuan Agong, as well as discussions related to rulers' privileges and religious observances. The Conference's other role in the federal governance of the country is to give consent to amendments of certain entrenched provisions of the federal constitution, namely those pertaining to the status of the rulers, the special privileges of the Bumiputra, the status of the Malay language as the national language, and the status of Islam as the religion of the federation.


title: Monarchies of Malaysia

text: Historically, various Malay kingdoms flourished on the Malay peninsula. The earliest kingdoms were influenced by Hindu culture, the most notable being Langkasuka in present-day Kedah. In the 15th century, the Malacca Sultanate became the dominant power on the peninsula. The Malacca Sultanate was the first Malay Muslim state based on the peninsula that was also a real regional maritime power. After the fall of Malacca in 1511, several local rulers emerged in the northern part of the peninsula which later fell under Siamese influence, while two princes of the Malaccan royal family founded Johor and Perak respectively. The Sultanate of Johor emerged as the dominant power on the peninsula. The vast territory of Johor led to some areas gaining autonomy, which gradually developed into independent states.


title: Monarchies of Malaysia

text: In the 19th century, as various infighting among the Malay aristocracy threatened British economic interests in the region, the British began a policy of intervention. The British concluded treaties with some Malay states, installing "residents" as advisors to the rulers, who soon became the "de facto" ruling powers of their states. These residents held power in everything except in religion affairs and Malay customs. In 1895, the governance of Negeri Sembilan, Pahang, Perak and Selangor were combined as the Federated Malay States, headed by a Resident General based in Kuala Lumpur. The British wrestled Kedah, Kelantan, Perlis and Terengganu from Siamese influence, and in turn they each received a British "advisor". Johor was the last state to succumb to British pressure, receiving an advisor in 1914. These five states were known as the Unfederated Malay States.


title: Monarchies of Malaysia

text: In 1946, after World War II, the British combined the Federated Malay States and the Unfederated Malay States, together with two of the Straits Settlements, Penang and Malacca, to form the Malayan Union which was headed by a British governor. Under the terms of the Union, the Malay rulers conceded all their powers to the British Crown except in religious matters. Widespread opposition by Malay nationalists led to the reform of Malayan Union to become the Federation of Malaya in 1948, in which the rulers were restored to their symbolic role as heads of state.


title: Monarchies of Malaysia

text: The present form of constitutional monarchy in Malaysia dates from 1957, when the Federation of Malaya gained independence. The rulers serve as constitutional heads of their states, with the state executive powers exercised by state governments elected by the people. The rulers elect among themselves a federal head of state, the Yang di-Pertuan Agong, with the federal executive powers exercised by an elected federal government. The form of constitutional monarchy was retained when Malaysia was formed in 1963.


title: Monarchies of Malaysia

text: According to the "Hikayat Merong Mahawangsa", the Kingdom of Kedah was founded around 630 CE by Maharaja Derbar Raja, who arrived from Gameroon, Persia. The Sultanate of Kedah was founded when the last Hindu king, Phra Ong Mahawangsa, converted to Islam in 1136. He took the name Sultan Mudzafar Shah. Sultan Mudzafar's descendants continue to rule Kedah today.


title: Monarchies of Malaysia

text: After centuries of subordination by Majapahit, Malacca, Siam and Terengganu, Long Muhammad, son of Long Yunus, declared himself Sultan in 1800 and gained recognition as a tributary by the Siamese. Control over Kelantan was transferred to the British under the Anglo-Siamese Treaty of 1909.


title: Monarchies of Malaysia

text: The state capital is Kota Bharu, while Kubang Kerian serves as the royal city. The main palace for ceremonial functions is Istana Balai Besar, while Istana Negeri serves as the current sultan's residence.