title: Bitches Brew

text: Reviewing for "Rolling Stone" in 1970, Langdon Winner said "Bitches Brew" shows Davis' music expanding in "beauty, subtlety and sheer magnificence", finding it "so rich in its form and substance that it permits and even encourages soaring flights of imagination by anyone who listens". He concluded that the album would "reward in direct proportion to the depth of your own involvement". "Village Voice" critic Robert Christgau deemed it "good music that's very much like jazz and something like rock", naming it the year's best jazz album and Davis "jazzman of the year" in his ballot for "Jazz & Pop" magazine. Years later, he had lost some enthusiasm about the album; in "" (1981), he called "Bitches Brew" "a brilliant wash of ideas, so many ideas that it leaves an unfocused impression", with Tony Williams' steadier rock rhythms from "In a Silent Way" replaced by "subtle shades of Latin and funk polyrhythm that never gather the requisite fervor". He concluded that the music sounded "enormously suggestive, and never less than enjoyable, but not quite compelling. Which is what rock is supposed to be."


title: Bitches Brew

text: Selling more than one million copies since it was released, "Bitches Brew" was viewed by some writers in the 1970s as what spurred jazz's renewed popularity with mainstream audiences that decade. As Michael Segell wrote in 1978, jazz was "considered commercially dead" by the 1960s until the album's success "opened the eyes of music-industry executives to the sales potential of jazz-oriented music". This led to other fusion records that "refined" Davis' new style of jazz and sold millions of copies, including "Head Hunters" (1973) by Herbie Hancock and George Benson's 1976 album "Breezin'". Tom Hull, who would later become a jazz critic, has said, "Back in the early '70s we used to listen to "Bitches Brew" as late night chill-out music – about the only jazz I ran into at the time." According to independent scholar Jane Garry, "Bitches Brew" defined and popularized the jazz fusion genre, also known as jazz-rock, but it was hated by a number of purists. Jazz critic and producer Bob Rusch recalled, "this to me was not "great Black music", but I cynically saw it as part and parcel of the commercial crap that was beginning to choke and bastardize the catalogs of such dependable companies as Blue Note and Prestige... I hear it 'better' today because there is now so much music that is worse." Despite the controversy the album stirred among the jazz community, it nonetheless managed to top DownBeat's annual critics' poll in 1970.


title: Bitches Brew

text: "The Penguin Guide to Jazz" called "Bitches Brew" "one of the most remarkable creative statements of the last half-century, in any artistic form. It is also profoundly flawed, a gigantic torso of burstingly noisy music that absolutely refuses to resolve itself under any recognized guise." In 2003, the album was ranked number 94 on "Rolling Stone" magazine's list of the 500 greatest albums of all time (it went down one spot 9 years later). In the 2020 reboot of the list, the album's rank climbed to number 87. Along with this accolade, the album has been ranked at or near the top of several other magazines' "best albums" lists in disparate genres. The album was also included in the book "1001 Albums You Must Hear Before You Die".


title: Bitches Brew

text: Experimental jazz drummer Bobby Previte considered "Bitches Brew" to be "groundbreaking": "How much groundbreaking music do you hear now? It was music that you had that feeling you never heard quite before. It came from another place. How much music do you hear now like that?" Thom Yorke, singer of the English rock band Radiohead, cited it as an influence on their 1997 album "OK Computer": "It was building something up and watching it fall apart, that's the beauty of it. It was at the core of what we were trying to do." The singer Bilal names it among his 25 favorite albums, citing Davis' stylistic reinvention. Rock and jazz musician Donald Fagen criticized the album as "essentially just a big trash-out for Miles ... To me it was just silly, and out of tune, and bad. I couldn't listen to it. It sounded like [Davis] was trying for a funk record, and just picked the wrong guys. They didn't understand how to play funk. They weren't steady enough."


title: Bryan Gil

text: Bryan Gil Salvatierra (born 11 February 2001) is a Spanish professional footballer who plays as a winger for Premier League club Tottenham Hotspur and the Spain national team.


title: Bryan Gil

text: Gil began his professional career at Sevilla, and also had loan spells with Leganés and Eibar in La Liga, totalling 54 games and six goals.


title: Bryan Gil

text: Gil won a silver medal at the 2020 Olympics with Spain's under-23 team. He made his senior international debut in 2021.


title: Bryan Gil

text: Born in L'Hospitalet de Llobregat, Barcelona, Catalonia, Gil and his family moved to Barbate, Andalusia when he was a child and he was mainly raised there. In 2012, he joined Sevilla FC's youth setup, moving there from his hometown side Barbate CF. Promoted to the reserves ahead of the 2018–19 season, he made his senior debut on 26 August 2018, starting in a 0–1 Segunda División B home loss against UD Ibiza.


title: Bryan Gil

text: Gil scored his first senior goal on 8 September 2018, netting the equaliser in a 2–1 home win against San Fernando CD. On 12 December, already a regular starter for the B-side, he renewed his contract until 2022. On 23 February 2019, he was given a straight red card in a 2–1 win at Granada CF B, and two teammates were also sent off for arguing the dismissal.


title: Bryan Gil

text: Gil made his first team – and La Liga – debut on 6 January 2019, coming on as a late substitute for goalscorer Wissam Ben Yedder in a 1–1 home draw against Atlético Madrid. He made ten more appearances – all off the bench – in his first season for the team, and scored on 25 April to conclude a 5–0 win over Rayo Vallecano at the Ramón Sánchez Pizjuán Stadium; the strike made him the first child of the 21st century to net in Spain's top flight.


title: Bryan Gil

text: On 29 November 2019, Gil scored his first goal in European competition when he scored in a UEFA Europa League game against Qarabağ FK which ended 2–0 in favour of Sevilla. The following 31 January, he moved to fellow top tier side CD Leganés on loan for the remainder of the season. On 19 July 2020, Gil scored against Real Madrid in a 2–2 home draw on the final day of the season.


title: Bryan Gil

text: Gil was loaned to fellow top tier side SD Eibar for the 2020–21 campaign on 5 October 2020, along with teammate Alejandro Pozo. He scored four goals and assisted as many, as the team ended the season relegated.


title: Bryan Gil

text: Gil signed for Tottenham Hotspur at the beginning of the 2021–22 season in a fee part-exchange deal with Argentine Erik Lamela heading to Sevilla. Sky Sports reported the initial fee of £21.6 million, and the contract length was for five years.


title: Bryan Gil

text: Gil made his debut for the club on 19 August 2021 by starting in the UEFA Europa Conference League first leg tie against Paços de Ferreira, which ended in a 1–0 defeat. Ten days later, he made his Premier League debut in a 1–0 home win over Watford as an 88th-minute replacement for goalscorer Son Heung-min. His progress was limited by a thigh injury against Burnley in October, followed by a COVID-19 diagnosis in December.


title: Bryan Gil

text: Having played just 85 minutes over nine league games, Gil was linked to a move back to La Liga in January 2022, to either Real Sociedad or Valencia. On the last day of the month, he was loaned to the latter for the remainder of the season. He made 17 total appearances for the club, including their penalty shootout defeat to Real Betis in the 2022 Copa del Rey Final on 23 April, in which he came on for goalscorer Hugo Duro with five minutes of regulation time remaining.


title: Bryan Gil

text: During the Summer break Gil returned to Spurs and was included in the club's tour of Korea. Gil has made a number of appearances off the bench and notably on the 12 October, he came off the bench in the Champions League and won his Spurs side a penalty in stoppage time against Eintracht Frankfurt.


title: Bryan Gil

text: Gil was a member of the Spain under-19 team that won the 2019 UEFA European Championship in Armenia, starting in the 2–0 final win over neighbours Portugal.


title: Bryan Gil

text: In March 2021, Gil received his first call-up to the Spain national team for the group stage of the 2022 FIFA World Cup qualification. He made his debut on 25 March 2021 against Greece, as a 65th-minute substitute for Sergio Canales in a 1–1 draw in Granada.


title: Bryan Gil

text: Gil won a silver medal at the 2020 Olympic tournament in Japan, delayed until the following year due to the COVID-19 pandemic.


title: Buick Riviera

text: The Buick Riviera is a personal luxury car that was marketed by Buick from 1963 to 1999, with the exception of the 1994 model year.


title: Buick Riviera

text: As General Motors' first entry into the personal luxury car market segment, the Riviera was highly praised by automotive journalists upon its high-profile debut. It was a ground-up design on a new GM E platform debuting for the 1963 model year and was also Buick's first unique Riviera model.


title: Buick Riviera

text: Unlike its subsequent GM E platform stablemates, the Oldsmobile Toronado and Cadillac Eldorado, the Riviera was initially a front engine/rear-wheel drive platform, switching to front-wheel drive starting with the 1979 model year.


title: Buick Riviera

text: While the early models stayed close to their original form, eight subsequent generations varied substantially in size and styling. A total of 1,127,261 Rivieras were produced.


title: Buick Riviera

text: The Riviera name was resurrected for two concept cars that were displayed at auto shows in 2007 and in 2013.


title: Buick Riviera

text: The name "Riviera", Italian for "coastline", was chosen to evoke the allure and affluence of the French Riviera. It first entered the Buick line in 1949, as the designation for the new two-door pillarless hardtop, described in advertising as "stunningly smart". The Buick Roadmaster Riviera coupe (along with the Cadillac Coupe de Ville and Oldsmobile 98 Holiday coupe) constituted the first mass production use of this body style, which was to become popular over the next 30 years. Buick added a two-door Riviera hardtop to the Super the following year, the Special in 1951, and the Century upon its return, after a 12-year absence, in 1954.


title: Buick Riviera

text: From 1951 to 1953 the "Riviera" designation was given to the existing long-wheelbase versions of the four-door Buick Roadmaster and Super sedans. The 1951–53 Buick Roadmaster and Super four-door Riviera sedans feature more standard features, more plush interior trim, and a wheelbase (and overall length) that is longer than a regular Buick Roadmaster or Super four-door sedan. The 1951–52 Buick Super four-door Riviera sedan is still shorter in wheelbase and length than the regular Buick Roadmaster and shorter than the Roadmaster four-door Riviera sedan. In 1953, with the move from the Fireball straight-eight to the more compact Fireball V8 engine, the Roadmaster and Super four-door Riviera sedans became the same length.


title: Buick Riviera

text: In the middle of the 1955 model year, Buick and Oldsmobile introduced the world's first mass-produced four-door hardtops, with Buick offering it only on the Century and Special models, and the "Riviera" designation was also applied to these body styles. Four-door Riviera hardtops were added to the Roadmaster and Super lines at the beginning of the following model year. However, since it was a body style designation and not a model, the Riviera name does not usually appear on the car.


title: Buick Riviera

text: In 1959, Buick became much more selective in applying the Riviera name. From then until 1962 it only was used to denote a premium trimmed six-window hardtop style which it initially shared exclusively with Cadillac (the Oldsmobile 98 would receive it in 1961) and was available only on the Electra 225. The last usage of the term "Riviera" to describe a luxury trim level was 1963, as the formal designation of the #4829 Electra 225 Riviera four-door hardtop, the same year the E-body model two-door hardtop coupe Riviera made its debut.


title: Buick Riviera

text: In the late 1950s, GM lacked a personal luxury car to compete with the highly successful Ford Thunderbird—a uniquely styled, two-door that had dramatically increased in popularity when expanded from a two-seater to a four-passenger car and the Chrysler 300C. To fill this gap, an experimental Cadillac design, the XP-715, was created, dubbed the "LaSalle" after a former GM luxury marque. Its angular look was reportedly inspired by GM styling chief Bill Mitchell's visit to London during the period, when he was struck by the sight of a custom-bodied Rolls Royce. He later said that "knife-edged" styling was what he wanted for the new model, but with a lower profile. The design itself was penned by stylist Ned Nickles.


title: Buick Riviera

text: When Cadillac passed on the venture in 1960 the project was thrown open for competition by the other GM Divisions. Buick, desperate to revive its flagging sales, won the competition by enlisting the aid of the McCann-Erickson advertising agency to create its presentation. Initially referred to as the "Buick LaSalle" and later "Buick Riviera" concept cars, the finished design was adapted to a shortened version of Buick's existing cruciform frame. It was again introduced as a concept car in 1963 called the Buick Riviera Silver Arrow.


title: Buick Riviera

text: The production Riviera was introduced on October 4, 1962, as a 1963 model, its distinctive bodyshell was unique to the marque, unusual for a GM product. The design was substantially the same as the original, less expensively hidden headlights concealed in the fender grilles. The elegant ground-up styling sported the new "Coke bottle look" introduced the year before on the arresting Studebaker Avanti, with a tapered midsection surrounded by flaring fenders. There was no trace of the "Sweepspear" used on beltlines of earlier Buicks with the Riviera package.


title: Buick Riviera

text: It rode a cruciform frame similar to the standard Buick frame, but shorter and narrower, with a narrower track. Its wheelbase of and overall length of were and shorter, respectively, than a Buick LeSabre, but slightly longer than a contemporary Thunderbird. At , it was about lighter than either. It shared the standard Buick V8 engines, with a displacement of either or , and the unique continuously variable design twin turbine automatic transmission. Power brakes were standard, using Buick's massive "Al-Fin" (aluminum finned) drums of diameter. Power steering was standard equipment, with an overall steering ratio of 20.5:1, giving 3.5 turns lock-to-lock.


title: Buick Riviera

text: The Riviera's suspension used Buick's standard design, with double wishbones in the front and a live axle located by trailing arms and a lateral track bar in the rear, but the roll centers were lowered to reduce body lean. Although its coil springs were actually slightly softer than other Buicks, the Riviera's lighter weight made its ride somewhat firmer. While still biased towards understeer, contemporary testers considered it one of the most driveable American cars, with an excellent balance of comfort and agility.


title: Buick Riviera

text: Buick's "Nailhead" V-8 was initially the only available engine, fitted with dual exhaust as standard equipment, and the turbine drive the only transmission. Base price was $4,333 ($ in dollars ), running upwards of $5,000 delivered with typical options ($ in dollars ). Buick announced an optional version of the Nailhead in December 1962. Total production was deliberately limited to 40,000 vehicles (in a year that Buick sold 440,000 units overall) to emphasize the Riviera's exclusivity and to increase demand; only 2,601 were delivered with the delayed availability larger engine in the 1963 model year.


title: Buick Riviera

text: With the same power as the bigger Buicks and less weight, the Riviera had improved all-around performance: "Motor Trend" recorded in 8 seconds or less, the standing quarter mile in about 16 seconds, and an observed top speed of . Fuel economy was a . Front leg room was 40.1 inches.


title: Buick Riviera

text: Inside, the Riviera featured a luxurious four-place cabin with front bucket seats and bucket-style seats in the rear. A center console with a floor shifter and storage compartment built into the instrument panel divided the front. Upholstery choices included all-vinyl, cloth and vinyl, or optional leather. A deluxe interior option included real walnut inserts on the doors and below the rear side windows. Extra-cost options included a tilt steering wheel, power windows, power driver's seat, air conditioning, a remote-controlled side-view mirror, and white sidewall tires.


title: Buick Riviera

text: Minimal trim and mechanical changes were made for 1964, with the most identifiable distinguishing features being a raised stylized "R" hood emblem and "R" emblems replacing the Buick crests in the taillight lenses. The interior is distinguished by moving the heater controls from controls under the dashboard eyebrow to slide controls in the forward fairing of the center console. Leather was dropped as an option, and the Dynaflow twin-turbine transmission was replaced by a new three-speed Super Turbine 400. This was a GM Turbo Hydra-Matic. It used a two-speed "D" and 'L" selector, but could automatically downshift from third to second until the car reached a suitable speed to downshift to first. This was the first year of the stylized "R" emblem, a trademark that would continue throughout the remainder of Riviera's 36-year production run. The engine was upgraded to the previously optional V8. A 'Super Wildcat' version was available, with dual Carter AFB four-barrel carburetors.


title: Buick Riviera

text: In 1965 the V8 returned as the standard engine, and the "Gran Sport" version made its debut, powered by the Super Wildcat V8, a 360 hp engine equipped with two Carter 625 CFM carburetors, a distributor with different advance, and outfitted with a more aggressive 3.42 axle ratio. A heavy-duty suspension was the separate H2 option but was not part of the Gran Sport option. It offered a quicker ratio steering box and firmer rated springs. The Super Turbine 400 transmission now had a variable pitch torque converter, but was fitted with a three-speed gear selector. The Gran Sport stock dual exhaust pipes were increased from to inside diameter and had fewer turns to reduce backpressure. Externally, the headlamps, now vertically arranged, were hidden behind clamshell doors in the leading edges of each fender, as had been in the original design. The non-functional side scoops between the doors and rear wheel arches were removed, and the taillights moved from the body into the rear bumper. A vinyl roof became available as an option, offered only in black, and the tilt steering wheel, optional in previous years, was now standard equipment.


title: Buick Riviera

text: Total sales for the 1963 through 1965 model years was 112,244. The Riviera was well received by the motoring press and considered a great success, giving the Thunderbird its first real competition as America's preeminent personal luxury car.


title: Buick Riviera

text: It has since earned Milestone status from the Milestone Car Society. Jaguar founder and designer Sir William Lyons remarked that Mitchell had done "a very wonderful job," and Sergio Pininfarina declared it "one of the most beautiful American cars ever built; it has marked a very impressive return to simplicity of American car design." At its debut at the Paris Auto Show, Raymond Loewy said the Riviera was the most handsome American production car—apart from his own Studebaker Avanti, in his view the Riviera's only real competition for 1963. The first-generation Riviera is considered a styling landmark and has become a collectible car.


title: Buick Riviera

text: The Riviera was redesigned for the 1966 model year. It retained its cruciform X-frame, powertrain, and brakes, but its curvaceous new body was longer, wider, and heavier. Vent windows, a feature GM had introduced in the 1930s, were absent. Headlamps remained concealed, but now pivoted behind the grille when not in use, and they were once again horizontally arranged. The car's added bulk slowed acceleration with the unchanged 425 engine. The Gran Sport package remained available as an option. Rear seat belts and AM/FM radio were optional.


title: Buick Riviera

text: The new front-wheel drive Oldsmobile Toronado shared the Riviera platform, and, a year later, the also front-wheel drive Cadillac Eldorado; however, the Riviera itself retained the rear-wheel drive layout.


title: Buick Riviera

text: Inside, the four-place cabin with front and rear bucket seats and center console were replaced by a choice of bucket seats or conventional bench seats as standard equipment, making the Riviera a full six-passenger car for the first time. Optionally available was a Strato-bench seat with armrest or Strato bucket seats with either a short consolette or a full-length operating console with a "horseshoe" shaped floor shifter and storage compartment. Both the buckets and Strato-bench seat were available with a reclining seat option for the passenger's side. Sales for 1966 rebounded to 45,308, a new record.


title: Buick Riviera

text: The most significant change for 1967 was Buick's replacement of its venerable 425 "Nailhead" with an entirely new V8. Its and of torque were a performance improvement. Gasoline mileage improved slightly, but remained low. Powerful disc brakes with Bendix four-piston calipers became optional for the front wheels but most Riviera continued to be ordered with Buick's highly capable ribbed aluminum brake drums. Cosmetically, changes were few and were limited to the addition of a wide, full-width, center-mounted horizontal chrome grille bar that stretched over the headlight doors and outboard parking lights. Sales eased to 42,799 for the 1967 model year. The Riviera had full instrumentation.


title: Buick Riviera

text: 1967 saw the introduction of U.S. mandated safety equipment to improve occupant protection during a crash, including an energy-absorbing steering column, non-protruding control knobs, 4-way hazard flasher, soft interior surfaces, locking seatbacks (on 2-door models), a dual-circuit hydraulic braking system (with warning light), and shoulder belt anchors. The Rivieras complied on all counts and featured the full range of safety features.


title: Buick Riviera

text: 1968 models had reshaped loop-type bumpers that surrounded both the vehicle's recessed crosshatch front grille and tail lamps. Hidden wiper arms made their debut. Federally mandated side marker lights appeared, as inverted trapezoids on the lower leading edges of the front fenders, and circular in the rear. The interior was restyled and for the first time shared its instrument panel with the other full-size Buick models. Shoulder belts for front outboard occupants were made standard on all cars built from January 1, 1968. Mechanically, the transmission lost its variable pitch torque converter. A tilt steering wheel was standard. Sales set another new record in 1968, as 49,284 units were sold.


title: Buick Riviera

text: Minor styling changes took place again in 1969, with grilles gaining a pattern of finely spaced, slim vertical bars overlaid by two wider horizontal bars, which jutted forward at their inboard edges. Front marker lights became far shorter and square. Inside, front outboard passengers received new headrests. The ignition switch was moved from the instrument panel to the steering column and locked the steering wheel and selector lever when the key was removed (a security feature that became mandatory for the 1970 model year). Chrome side trim was revised, as well. At the rear, the reverse lights moved from the rear bumper to new three-section tail-light lenses. Sales for 1969 improved again, to 52,872.


title: Buick Riviera

text: The 1970 Riviera was restyled, incorporating design cues from Bill Mitchell's 1968 "Silver Arrow II" concept car. Exposed quad headlamps were nearly flush-mounted, while the new front bumper wrapped around and over the new vertical bar grille, set between the headlamp pods. A newly optional side trim feature accented the large coupe's flowing lines. Skirted rear wheels became standard, with exposed wheels an option. At the rear, a new rear bumper/taillight motif was seen. The engine was upgraded to , the largest engine Buick offered to date, rated at gross, net, and over of torque. Despite the fact that 1970 sales dropped to 37,366, the second-generation Riviera proved more successful than the first, with 227,669 units sold over five the years.


title: Buick Riviera

text: The Riviera was radically redesigned for the 1971 model year with flowing and dramatic "boat-tail" styling. Designed under Bill Mitchell's direction, it was penned by Jerry Hirshberg, future head of design for Nissan, mating the two-piece vee-butted fastback rear window, inspired by the 1963 Corvette Sting Ray coupe, to the Riviera's platform.


title: Buick Riviera

text: The design was originally intended for the smaller A-body or its related G-body, as shown by a full scale clay model of an A-body based boat-tail Riviera recently revealed. Given the late stage of the 1968-72 A/G platform evolution and accretive cost to add another version to it, GM Management decreed that the next Riviera use the full sized GM B platform body—expanded for 1971 by in wheelbase and more than heavier— which produced controversial looks, making for a sharp departure from those of the Toronado and Eldorado. ("Collectible Automobile" ran an article about 1971–76 full-sized Buicks in which one sketch design for their 2-door coupes which was rejected resembled the 1971–73 Riviera).


title: Buick Riviera

text: This generation introduced a much more visual representation of the "sweepspear", with a more faithful representation to the version that appeared on 1950s Buicks in both the side molding and beltline. Large, round wheel openings were intended to convey more of a sporty air. The only engine available was Buick's own 455 ci V8 engine producing , with with the Gran Sport (GS) package.


title: Buick Riviera

text: The 455 engine had a lower compression ratio to meet EPA emissions requirements, together with the shift from SAE gross to SAE net ratings this reduced claimed power to , with in the Gran Sport. Performance remained reasonably brisk, with a 0–60 mph time of 8.1 seconds for the GS, but the Riviera's sporty image was rapidly fading. One noteworthy advance was Buick's Max Trac limited-slip differential. The 1971 Riviera also features GM's "Full-Flo" ventilation system and two large deck lid louvers are prominent on the trunk lid.


title: Buick Riviera

text: Despite these features, Riviera sales for 1971 dropped to 33,810, the lowest to date. The 1972 Riviera received a new, egg-crate grille, more substantial front bumpers to prepare for the new 5-mph impact legislation, restyled taillight trim, and the louvers were removed from the trunk lid. The 1972 Riviera also featured a redesigned ventilation system, and the 455 engine switched to net power ratings, or in the Gran Sport, although the actual drop in net power was only . Sales remained stagnant at 33,728, a drop of 82 from the prior year.


title: Buick Riviera

text: For 1973, the Riviera underwent a number of changes. The front bumper was redesigned to be thicker and featured bumper guards as standard in order to meet 1974 impact-bumper standards, the grille was switched back to horizontal slats, and the front lamps were moved from the bumper and were now integrated into the headlights, wrapping around the corners of the car. Sluggish sales of the third generation Riviera led GM to believe that the boattail deck lid was too radical for most customers' tastes, so in 1973 it was blunted and made slightly shorter. The taillights, meanwhile, were moved down from the sheet metal and into the bumper, and the rear license plate location was moved from the left side of the bumper to the center. The engine became standard, with with the Stage One package. This also included a limited-slip differential and a chrome-plated air cleaner. The "Gran Sport" package was still available as a separate option package consisting of a ride-and-handling package that included a rear stabilizer bar, JR78-15 whitewall steel-belted radial tires, a specially tuned "radial roadability" suspension, additional sound insulation and special "Gran Sport" badging. The design changes however only led to a marginal increase in sales, with 34,080 being produced for the model year.


title: Buick Riviera

text: Although carrying over the same platform, mechanicals, and some body panels seen on the "Third Generation" Riviera, Buick replaced its distinctive 'boat tail' roofline with a more conventional-looking "Colonnade" treatment which was more in line with its LeSabre and Electra brethren than its front-wheel drive cousins. This turned the car from a hardtop coupe into a pillared coupe, as it featured wide B pillars and fixed quarter opera windows. A landau half-vinyl roof option was available. The car did retain its forward-jutting grille, albeit in a slightly modified form. Thus modified, the car looked far less distinctive than its predecessors, and even its platform mates, the Oldsmobile Toronado and Cadillac Eldorado.


title: Buick Riviera

text: The tamer-looking Riviera was no lighter, and its standard 455 V8 lost more power, dropping to and for standard and Stage One models respectively. Max Trac was dropped from the option list after 1974 due to a lack of buyer interest. The revised styling did not improve sales, which fell to 20,129 in 1974, although it is impossible to determine how much this was a result of the energy crisis and how much was due to the tame appearance. This generation introduced a novelty that later became federally mandated in a modified form, two high-mounted taillights above the trunk and below the rear window, which was shared on its platform twin the Toronado.


title: Buick Riviera

text: For 1975, the Riviera received an updated front fascia, which lost its forward-jutting theme through the redesign of the fiberglass front end cap. Quad rectangular headlights were mounted horizontally. The new vertical-bar grille echoed the "stand-up" theme that many GM cars of the day incorporated. Parking lights wrapped around the fender sides. The Stage One performance package was dropped for 1975, though the Gran Sport handling package would continue to be offered. The standard engine's output dipped to . Sales for 1975 were 17,306.


title: Buick Riviera

text: Minor changes greeted 1976 models, the most notable of which was a new crosshatch grille insert. The Gran Sport handling package was replaced by an 'S/R' package that had similar sporting pretensions. Sales rallied slightly to 20,082 for 1976.


title: Buick Riviera

text: Buick downsized the Riviera for 1977 onto the new smaller GM B platform. While the other E-bodies were front wheel drive since 1966 (1967 for Cadillac's Eldorado), the Buick E platform used a rear-wheel-drive B-body undercarriage (along with the cruciform frame of pre-1965 GMs for the 1966–70 generation). All B-bodies (including C and D platform GM RWDs) were downsized for the 1977 model year which prompted the short-lived 1977/78 generation.


title: Buick Riviera

text: It was, in most respects, a Buick LeSabre coupe with unique styling (with quarter windows mimicking the 1975–78 Cadillac Eldorado). Unlike its LeSabre counterpart, the front fascia is vertical as opposed to slanted. It was reduced to a wheelbase of , down , and an overall length of , down . Weight was reduced by appoximately . The 455 engine was replaced by a Buick V8 engine with or an Oldsmobile-built with . California models had a Oldsmobile 350.


title: Buick Riviera

text: Sales were up modestly to 26,138 for 1977 and then fell to 20,535 for 1978, although this was a stopgap model until the all-new E-body cars would be ready for 1979. The 1977 and 1978 Rivieras were produced on the downsized GM B platform before the 1979 redesign on the FWD E-platform.


title: Buick Riviera

text: For 1978, a special "LXXV" edition was released to commemorate Buick's 75th anniversary on the market. Production total was 2,889 and included special silver & black paint with gray leather seats with black trim, four-wheel disc brakes, brushed chrome trim, deep pile carpeting, and special LXXV name plates.


title: Buick Riviera

text: The 1979 model year was the debut of the first front wheel drive Riviera, which was also the first front-drive production model in Buick history. Built on a wheelbase, it once again shared its mechanical design and platform with the Cadillac Eldorado and Oldsmobile Toronado. The Olds 403 and Buick 350 were dropped, but the Olds 350 remained, as did a new turbocharged Buick V6 engine of displacement with which was installed in the Riviera S-Type, shared with the Regal Sport Coupe turbo for model year 1980. The Riviera became "Motor Trend" Car of the Year. Sales more than doubled, to 52,181 for 1979 and 48,621 for the similar 1980 models.


title: Buick Riviera

text: 1981 saw the Turbo renamed T-Type and the demise of the 350 engine in favor of the Oldsmobile-built with (phased in during the 1980 MY). The standard engine was now Buick's V6, and a new option was an Oldsmobile diesel engine with a mere offered through 1985. 1982 also saw the first-ever Riviera convertible, although relatively few were built, owing to a high price - US$23,944 ($ in dollars ). The Riviera convertible was available in only two color choices-white or red firemist with the only interior color of red leather. A was chosen to be the pace car at the 1983 Indianapolis 500, tuned to produce . Most convertible Rivieras had the V8 engine, which saw an increase in rated SAE net HP to 150 for both convertibles and coupes fitted with it from 1982 through the 1985 model year.


title: Buick Riviera

text: In 1983 a special edition of 500 "Riviera XX" was offered, celebrating twenty years since the introduction of the first Riviera (502 were built in the end). These have a special two-tone exterior paint, real wire wheels, a leather, and walnut interior as well as 24-karat gold plated "Riviera XX" badging. The Riviera XX also received a special grille, which then became part of the 1984 model year facelift model. Overall sales made the 1980s Riviera a great success, reaching 65,305 for the 1985 model year.


title: Buick Riviera

text: The E-body coupes were converted to unibody construction and further downsized for 1986 to a wheelbase. The V6 was now the only engine, rated initially at SAE and of torque. It used the Turbo-Hydramatic 440-T4 automatic with a 2.84:1 final drive ratio.


title: Buick Riviera

text: This generation featured an advanced electronic instrumentation display on a dash-mounted CRT. The CRT controlled the vehicle's climate control system and stereo, and also supplied advanced instrumentation such as a trip computer and maintenance reminder feature. Four-wheel disc brakes were standard. With a choice of three suspension packages available, up to the performance-oriented FE3 setting, handling was notably improved. The Riviera placed fourth for "Motor Trend"s 1986 Car of the Year contest. This generation saw the installation of Dynaride, which was an air compressor that would pressurize the rear Chapman Struts to maintain a level overall ride height. A badge was installed on the dashboard to the left of the steering column on all vehicles equipped. It was not available on vehicles equipped with Gran Touring Suspension.


title: Buick Riviera

text: Fuel economy was also notably improved for the 1986 Riviera but the investment in the downsized, transverse engine front wheel drive platform resulted in a substantial price increase to $19,831 ($ in dollars ) for the base model and $21,577 for the T-Type ($ in dollars ). The smaller exterior dimensions and lack of a V8 led to sales plummeting to 22,138 for 1986, 15,223 for 1987, and only 8,625 for 1988. 1988 also saw the introduction of Buick's new Reatta coupe, a two-seat personal luxury car.


title: Buick Riviera

text: The Riviera was restyled for 1989, adding to the overall length (on an unchanged wheelbase). Sales improved to 21,189 for 1989, but dropped to a low of 4,555 for 1993, the abbreviated final model year of this generation. The last 1993 Riviera rolled off the Detroit/Hamtramck Assembly plant line on December 10, 1992.


title: Buick Riviera

text: After a hiatus in 1994, the Riviera returned in 1995 with radical styling that departed from the previous generations' traditional image. A naturally aspirated 3800 V6 was standard, with a supercharged version rated at and available as an option. Rivieras were now built in Orion Township, Michigan, riding the same Cadillac-derived G platform as the 4-door Oldsmobile Aurora. The first of 41,422 Rivieras made in 1995 rolled off the assembly line on May 23, 1994.


title: Buick Riviera

text: In 1996, supercharged versions saw an increase in power to and 280 lb·ft (380 N·m), as well as the 4T60E-HD transmission. 18,036 Rivieras were manufactured in 1996.


title: Buick Riviera

text: 1997 saw suspension revisions, removing excess weight. An upgraded 4T65E-HD transmission featuring a larger torque converter and heavy-duty gearbox were added. 18,827 were made in 1997.


title: Buick Riviera

text: For 1998, the supercharged V6 became standard. GM's OnStar service was added as an option, along with minor interior design changes and features including passenger heated seats. A total of 10,953 units were produced for 1998.


title: Buick Riviera

text: With sales of all coupes declining in the North American market, GM decided to discontinue the Riviera. 1999 was the car's last model year with production of 1,956 cars ceasing on November 25, 1998. The final 200 cars had special silver paint and trim, and were denoted "Silver Arrow" models, a designation which hearkened back to several Silver Arrow show cars that had been built off Riviera bodies by Bill Mitchell.


title: Buick Riviera

text: Eighth-generation Rivieras received the most powerful V6 Buick engine since the Grand Nationals of the 1980s. The supercharged OHV V6 provided high torque and acceleration allowing 0 to in under 7 seconds, and turning the mile in 15.5 seconds. Supercharged Rivieras achieved a fuel efficiency figure of 18/27 (city/highway mpg).


title: Buick Riviera

text: At the 2007 Shanghai Motor Show, Buick debuted a concept coupe named Riviera, based on the GM Epsilon II platform. The concept was later shown at the 2008 North American International Auto Show.


title: Buick Riviera

text: It was designed by the Pan Asia Technical Automotive Center (PATAC). The design was inspired by classic Buicks, ancient Chinese artifacts, and modern electronic icons. It includes "icy green" backlighting, Shell Blue body, gull-wing doors, a 2+2 seating configuration, and 21-inch 10-spoke forged aluminum wheels.


title: Buick Riviera

text: Another concept Riviera was shown at the 2013 Shanghai Motor Show, again developed by the Pan Asia Technical Automotive Center PATAC. It has gull-wing doors and a plug-in electric driveline as well as four wheel steering, electromagnetically controlled suspension with air springs, built in 4G LTE connection, transparent A pillar and wireless charging.


title: Factor analysis

text: Factor analysis is a statistical method used to describe variability among observed, correlated variables in terms of a potentially lower number of unobserved variables called factors. For example, it is possible that variations in six observed variables mainly reflect the variations in two unobserved (underlying) variables. Factor analysis searches for such joint variations in response to unobserved latent variables. The observed variables are modelled as linear combinations of the potential factors plus "error" terms, hence factor analysis can be thought of as a special case of errors-in-variables models.


title: Factor analysis

text: Simply put, the factor loading of a variable quantifies the extent to which the variable is related to a given factor.


title: Factor analysis

text: A common rationale behind factor analytic methods is that the information gained about the interdependencies between observed variables can be used later to reduce the set of variables in a dataset. Factor analysis is commonly used in psychometrics, personality psychology, biology, marketing, product management, operations research, finance, and machine learning. It may help to deal with data sets where there are large numbers of observed variables that are thought to reflect a smaller number of underlying/latent variables. It is one of the most commonly used inter-dependency techniques and is used when the relevant set of variables shows a systematic inter-dependence and the objective is to find out the latent factors that create a commonality.


title: Factor analysis

text: The model attempts to explain a set of formula_1 observations in each of formula_2 individuals with a set of formula_3 "common factors" (formula_4) where there are fewer factors per unit than observations per unit (<math>k). Each individual has formula_3 of their own common factors, and these are related to the observations via factor "loading matrix" (formula_6), for a single observation, according to


title: Factor analysis

text: where observation matrix formula_22, loading matrix formula_23, factor matrix formula_24, error term matrix formula_25 and mean matrix formula_26 whereby the formula_20th element is simply formula_28.


title: Factor analysis

text: Note that for any orthogonal matrix formula_43, if we set formula_44 and formula_45, the criteria for being factors and factor loadings still hold. Hence a set of factors and factor loadings is unique only up to an orthogonal transformation.


title: Factor analysis

text: Suppose a psychologist has the hypothesis that there are two kinds of intelligence, "verbal intelligence" and "mathematical intelligence", neither of which is directly observed. Evidence for the hypothesis is sought in the examination scores from each of 10 different academic fields of 1000 students. If each student is chosen randomly from a large population, then each student's 10 scores are random variables. The psychologist's hypothesis may say that for each of the 10 academic fields, the score averaged over the group of all students who share some common pair of values for verbal and mathematical "intelligences" is some constant times their level of verbal intelligence plus another constant times their level of mathematical intelligence, i.e., it is a linear combination of those two "factors". The numbers for a particular subject, by which the two kinds of intelligence are multiplied to obtain the expected score, are posited by the hypothesis to be the same for all intelligence level pairs, and are called "factor loading" for this subject. For example, the hypothesis may hold that the predicted average student's aptitude in the field of astronomy is


title: Factor analysis

text: The numbers 10 and 6 are the factor loadings associated with astronomy. Other academic subjects may have different factor loadings.


title: Factor analysis

text: Two students assumed to have identical degrees of verbal and mathematical intelligence may have different measured aptitudes in astronomy because individual aptitudes differ from average aptitudes (predicted above) and because of measurement error itself. Such differences make up what is collectively called the "error" — a statistical term that means the amount by which an individual, as measured, differs from what is average for or predicted by his or her levels of intelligence (see errors and residuals in statistics).


title: Factor analysis

text: The observable data that go into factor analysis would be 10 scores of each of the 1000 students, a total of 10,000 numbers. The factor loadings and levels of the two kinds of intelligence of each student must be inferred from the data.


title: Factor analysis

text: In the following, matrices will be indicated by indexed variables. "Subject" indices will be indicated using letters formula_46,formula_47 and formula_48, with values running from formula_49 to formula_1 which is equal to formula_51 in the above example. "Factor" indices will be indicated using letters formula_1, formula_53 and formula_54, with values running from formula_49 to formula_3 which is equal to formula_57 in the above example. "Instance" or "sample" indices will be indicated using letters formula_9,formula_15 and formula_3, with values running from formula_49 to formula_62. In the example above, if a sample of formula_63 students participated in the formula_64 exams, the formula_9th student's score for the formula_46th exam is given by formula_67. The purpose of factor analysis is to characterize the correlations between the variables formula_68 of which the formula_67 are a particular instance, or set of observations. In order for the variables to be on equal footing, they are normalized into standard scores formula_70:


title: Factor analysis

text: Observe that by doubling the scale on which "verbal intelligence"—the first component in each column of formula_29—is measured, and simultaneously halving the factor loadings for verbal intelligence makes no difference to the model. Thus, no generality is lost by assuming that the standard deviation of the factors for verbal intelligence is formula_49. Likewise for mathematical intelligence. Moreover, for similar reasons, no generality is lost by assuming the two factors are uncorrelated with each other. In other words:


title: Factor analysis

text: where formula_87 is the Kronecker delta (formula_88 when formula_89 and formula_49 when formula_91).The errors are assumed to be independent of the factors:


title: Factor analysis

text: Note that, since any rotation of a solution is also a solution, this makes interpreting the factors difficult. See disadvantages below. In this particular example, if we do not know beforehand that the two types of intelligence are uncorrelated, then we cannot interpret the two factors as the two different types of intelligence. Even if they are uncorrelated, we cannot tell which factor corresponds to verbal intelligence and which corresponds to mathematical intelligence without an outside argument.


title: Factor analysis

text: The values of the loadings formula_93, the averages formula_94, and the variances of the "errors" formula_31 must be estimated given the observed data formula_96 and formula_29 (the assumption about the levels of the factors is fixed for a given formula_29).


title: Factor analysis

text: The term on the left is the formula_100-term of the correlation matrix (a formula_101 matrix derived as the product of the formula_102 matrix of standardized observations with its transpose) of the observed data, and its formula_1 diagonal elements will be formula_49s. The second term on the right will be a diagonal matrix with terms less than unity. The first term on the right is the "reduced correlation matrix" and will be equal to the correlation matrix except for its diagonal values which will be less than unity. These diagonal elements of the reduced correlation matrix are called "communalities" (which represent the fraction of the variance in the observed variable that is accounted for by the factors):


title: Factor analysis

text: The sample data formula_106 will not exactly obey the fundamental equation given above due to sampling errors, inadequacy of the model, etc. The goal of any analysis of the above model is to find the factors formula_107 and loadings formula_80 which give a "best fit" to the data. In factor analysis, the best fit is defined as the minimum of the mean square error in the off-diagonal residuals of the correlation matrix:


title: Factor analysis

text: This is equivalent to minimizing the off-diagonal components of the error covariance which, in the model equations have expected values of zero. This is to be contrasted with principal component analysis which seeks to minimize the mean square error of all residuals. Before the advent of high-speed computers, considerable effort was devoted to finding approximate solutions to the problem, particularly in estimating the communalities by other means, which then simplifies the problem considerably by yielding a known reduced correlation matrix. This was then used to estimate the factors and the loadings. With the advent of high-speed computers, the minimization problem can be solved iteratively with adequate speed, and the communalities are calculated in the process, rather than being needed beforehand. The MinRes algorithm is particularly suited to this problem, but is hardly the only iterative means of finding a solution.


title: Factor analysis

text: If the solution factors are allowed to be correlated (as in 'oblimin' rotation, for example), then the corresponding mathematical model uses skew coordinates rather than orthogonal coordinates.


title: Factor analysis

text: The parameters and variables of factor analysis can be given a geometrical interpretation. The data (formula_106), the factors (formula_107) and the errors (formula_112) can be viewed as vectors in an formula_62-dimensional Euclidean space (sample space), represented as formula_114, formula_115 and formula_116 respectively. Since the data are standardized, the data vectors are of unit length (formula_117). The factor vectors define an formula_3-dimensional linear subspace (i.e. a hyperplane) in this space, upon which the data vectors are projected orthogonally. This follows from the model equation


title: Factor analysis

text: and the independence of the factors and the errors: formula_120. In the above example, the hyperplane is just a 2-dimensional plane defined by the two factor vectors. The projection of the data vectors onto the hyperplane is given by


title: Factor analysis

text: and the errors are vectors from that projected point to the data point and are perpendicular to the hyperplane. The goal of factor analysis is to find a hyperplane which is a "best fit" to the data in some sense, so it doesn't matter how the factor vectors which define this hyperplane are chosen, as long as they are independent and lie in the hyperplane. We are free to specify them as both orthogonal and normal (formula_122) with no loss of generality. After a suitable set of factors are found, they may also be arbitrarily rotated within the hyperplane, so that any rotation of the factor vectors will define the same hyperplane, and also be a solution. As a result, in the above example, in which the fitting hyperplane is two dimensional, if we do not know beforehand that the two types of intelligence are uncorrelated, then we cannot interpret the two factors as the two different types of intelligence. Even if they are uncorrelated, we cannot tell which factor corresponds to verbal intelligence and which corresponds to mathematical intelligence, or whether the factors are linear combinations of both, without an outside argument.


title: Factor analysis

text: The data vectors formula_114 have unit length. The entries of the correlation matrix for the data are given by formula_124. The correlation matrix can be geometrically interpreted as the cosine of the angle between the two data vectors formula_114 and formula_126. The diagonal elements will clearly be formula_49s and the off diagonal elements will have absolute values less than or equal to unity. The "reduced correlation matrix" is defined as


title: Factor analysis

text: The goal of factor analysis is to choose the fitting hyperplane such that the reduced correlation matrix reproduces the correlation matrix as nearly as possible, except for the diagonal elements of the correlation matrix which are known to have unit value. In other words, the goal is to reproduce as accurately as possible the cross-correlations in the data. Specifically, for the fitting hyperplane, the mean square error in the off-diagonal components


title: Factor analysis

text: is to be minimized, and this is accomplished by minimizing it with respect to a set of orthonormal factor vectors. It can be seen that


title: Factor analysis

text: The term on the right is just the covariance of the errors. In the model, the error covariance is stated to be a diagonal matrix and so the above minimization problem will in fact yield a "best fit" to the model: It will yield a sample estimate of the error covariance which has its off-diagonal components minimized in the mean square sense. It can be seen that since the formula_131 are orthogonal projections of the data vectors, their length will be less than or equal to the length of the projected data vector, which is unity. The square of these lengths are just the diagonal elements of the reduced correlation matrix. These diagonal elements of the reduced correlation matrix are known as "communalities":


title: Factor analysis

text: Large values of the communalities will indicate that the fitting hyperplane is rather accurately reproducing the correlation matrix. The mean values of the factors must also be constrained to be zero, from which it follows that the mean values of the errors will also be zero.


title: Factor analysis

text: Exploratory factor analysis (EFA) is used to identify complex interrelationships among items and group items that are part of unified concepts. The researcher makes no "a priori" assumptions about relationships among factors.


title: Factor analysis

text: Confirmatory factor analysis (CFA) is a more complex approach that tests the hypothesis that the items are associated with specific factors. CFA uses structural equation modeling to test a measurement model whereby loading on the factors allows for evaluation of relationships between observed variables and unobserved variables. Structural equation modeling approaches can accommodate measurement error and are less restrictive than least-squares estimation. Hypothesized models are tested against actual data, and the analysis would demonstrate loadings of observed variables on the latent variables (factors), as well as the correlation between the latent variables.


title: Factor analysis

text: Principal component analysis (PCA) is a widely used method for factor extraction, which is the first phase of EFA. Factor weights are computed to extract the maximum possible variance, with successive factoring continuing until there is no further meaningful variance left. The factor model must then be rotated for analysis.


title: Factor analysis

text: Canonical factor analysis, also called Rao's canonical factoring, is a different method of computing the same model as PCA, which uses the principal axis method. Canonical factor analysis seeks factors that have the highest canonical correlation with the observed variables. Canonical factor analysis is unaffected by arbitrary rescaling of the data.


title: Factor analysis

text: Common factor analysis, also called principal factor analysis (PFA) or principal axis factoring (PAF), seeks the fewest factors which can account for the common variance (correlation) of a set of variables.


title: Factor analysis

text: Image factoring is based on the correlation matrix of predicted variables rather than actual variables, where each variable is predicted from the others using multiple regression.


title: Factor analysis

text: Alpha factoring is based on maximizing the reliability of factors, assuming variables are randomly sampled from a universe of variables. All other methods assume cases to be sampled and variables fixed.


title: Factor analysis

text: Factor regression model is a combinatorial model of factor model and regression model; or alternatively, it can be viewed as the hybrid factor model, whose factors are partially known.


title: Factor analysis

text: Researchers wish to avoid such subjective or arbitrary criteria for factor retention as "it made sense to me". A number of objective methods have been developed to solve this problem, allowing users to determine an appropriate range of solutions to investigate. However these different methods often disagree with one another as to the number of factors that ought to be retained. For instance, the parallel analysis may suggest 5 factors while Velicer's MAP suggests 6, so the researcher may request both 5 and 6-factor solutions and discuss each in terms of their relation to external data and theory.


title: Factor analysis

text: Horn's parallel analysis (PA): A Monte-Carlo based simulation method that compares the observed eigenvalues with those obtained from uncorrelated normal variables. A factor or component is retained if the associated eigenvalue is bigger than the 95th percentile of the distribution of eigenvalues derived from the random data. PA is among the more commonly recommended rules for determining the number of components to retain, but many programs fail to include this option (a notable exception being R). However, Formann provided both theoretical and empirical evidence that its application might not be appropriate in many cases since its performance is considerably influenced by sample size, item discrimination, and type of correlation coefficient.


title: Factor analysis

text: Velicer's (1976) MAP test as described by Courtney (2013) “involves a complete principal components analysis followed by the examination of a series of matrices of partial correlations” (p. 397 (though note that this quote does not occur in Velicer (1976) and the cited page number is outside the pages of the citation). The squared correlation for Step “0” (see Figure 4) is the average squared off-diagonal correlation for the unpartialed correlation matrix. On Step 1, the first principal component and its associated items are partialed out. Thereafter, the average squared off-diagonal correlation for the subsequent correlation matrix is then computed for Step 1. On Step 2, the first two principal components are partialed out and the resultant average squared off-diagonal correlation is again computed. The computations are carried out for k minus one step (k representing the total number of variables in the matrix). Thereafter, all of the average squared correlations for each step are lined up and the step number in the analyses that resulted in the lowest average squared partial correlation determines the number of components or factors to retain. By this method, components are maintained as long as the variance in the correlation matrix represents systematic variance, as opposed to residual or error variance. Although methodologically akin to principal components analysis, the MAP technique has been shown to perform quite well in determining the number of factors to retain in multiple simulation studies. This procedure is made available through SPSS's user interface, as well as the "psych" package for the R programming language.


title: Factor analysis

text: Kaiser criterion: The Kaiser rule is to drop all components with eigenvalues under 1.0 – this being the eigenvalue equal to the information accounted for by an average single item. The Kaiser criterion is the default in SPSS and most statistical software but is not recommended when used as the sole cut-off criterion for estimating the number of factors as it tends to over-extract factors. A variation of this method has been created where a researcher calculates confidence intervals for each eigenvalue and retains only factors which have the entire confidence interval greater than 1.0.


title: Factor analysis

text: The Cattell scree test plots the components as the X-axis and the corresponding eigenvalues as the Y-axis. As one moves to the right, toward later components, the eigenvalues drop. When the drop ceases and the curve makes an elbow toward less steep decline, Cattell's scree test says to drop all further components after the one starting at the elbow. This rule is sometimes criticised for being amenable to researcher-controlled "". That is, as picking the "elbow" can be subjective because the curve has multiple elbows or is a smooth curve, the researcher may be tempted to set the cut-off at the number of factors desired by their research agenda.


title: Factor analysis

text: Variance explained criteria: Some researchers simply use the rule of keeping enough factors to account for 90% (sometimes 80%) of the variation. Where the researcher's goal emphasizes parsimony (explaining variance with as few factors as possible), the criterion could be as low as 50%.


title: Factor analysis

text: A Bayesian approach based on the Indian buffet process returns a probability distribution over the plausible number of latent factors.


title: Factor analysis

text: The unrotated output maximizes the variance accounted for by the first factor first, then the second factor, etc. The unrotated solution is orthogonal. This means that the correlation between the factors is zero. A disadvantage of using the unrotated solution is that usually most items load on the early factors and many items load substantially on more than one factor.


title: Factor analysis

text: Rotation serves to make the output easier to interpret by rotating the axes of the coordinate system to form a pattern of loadings where each item loads strongly on only one of the factors and more weakly on the other factors. Rotations can be orthogonal or oblique. Oblique rotation allows the factors to correlate.


title: Factor analysis

text: Varimax is the most commonly used rotation method. Varimax is an orthogonal rotation of the factor axes that maximizes the variance of the squared loadings of a factor (column) on all the variables (rows) in a factor loadings matrix. Each factor tends to have only few variables with large loadings by the factor. Varimax simplifies columns of the loadings matrix. This makes it as easy as possible to identify each variable with a single factor.


title: Factor analysis

text: Quartimax rotation is an orthogonal rotation that minimizes the number of factors needed to explain a variable. It simplifies the rows of the loadings matrix rather than the columns. Quartimax often produces a general factor that have loadings for many of the variables. This is close to the unrotated solution. Quartimax is useful if many of the variables are correlated so that a dominating factor can be expected.


title: Factor analysis

text: In many practical applications, it is unrealistic to assume that the factors are uncorrelated. Oblique rotations are preferred in this situation. Allowing for factors that are correlated with one another is especially applicable in psychometric research, since attitudes, opinions, and intellectual abilities tend to be correlated and it would be unrealistic to assume otherwise.


title: Factor analysis

text: Promax rotation is an alternative oblique rotation method that is computationally faster than the oblimin method and therefore is sometimes used for very large datasets.


title: Factor analysis

text: It can be difficult to interpret a factor structure when each variable is loading on multiple factors.


title: Factor analysis

text: Small changes in the data can sometimes tip a balance in the factor rotation criterion so that a completely different factor rotation is produced. This can make it difficult to compare the results of different experiments. This problem is illustrated by a comparison of different studies of world-wide cultural differences. Each study has used different measures of cultural variables and produced a differently rotated factor analysis result. The authors of each study believed that they had discovered something new, and invented new names for the factors they found. A later comparison of the studies found that the results were rather similar when the unrotated results were compared. The common practice of factor rotation has obscured the similarity between the results of the different studies.


title: Factor analysis

text: Higher-order factor analysis is a statistical method consisting of repeating steps factor analysis – oblique rotation – factor analysis of rotated factors. Its merit is to enable the researcher to see the hierarchical structure of studied phenomena. To interpret the results, one proceeds either by post-multiplying the primary factor pattern matrix by the higher-order factor pattern matrices (Gorsuch, 1983) and perhaps applying a Varimax rotation to the result (Thompson, 1990) or by using a Schmid-Leiman solution (SLS, Schmid & Leiman, 1957, also known as Schmid-Leiman transformation) which attributes the variation from the primary factors to the second-order factors.


title: Factor analysis

text: Factor analysis is related to principal component analysis (PCA), but the two are not identical. There has been significant controversy in the field over differences between the two techniques. PCA can be considered as a more basic version of exploratory factor analysis (EFA) that was developed in the early days prior to the advent of high-speed computers. Both PCA and factor analysis aim to reduce the dimensionality of a set of data, but the approaches taken to do so are different for the two techniques. Factor analysis is clearly designed with the objective to identify certain unobservable factors from the observed variables, whereas PCA does not directly address this objective; at best, PCA provides an approximation to the required factors. From the point of view of exploratory analysis, the eigenvalues of PCA are inflated component loadings, i.e., contaminated with error variance.


title: Factor analysis

text: Whilst EFA and PCA are treated as synonymous techniques in some fields of statistics, this has been criticised. Factor analysis "deals with "the assumption of an underlying causal structure": [it] assumes that the covariation in the observed variables is due to the presence of one or more latent variables (factors) that exert causal influence on these observed variables". In contrast, PCA neither assumes nor depends on such an underlying causal relationship. Researchers have argued that the distinctions between the two techniques may mean that there are objective benefits for preferring one over the other based on the analytic goal. If the factor model is incorrectly formulated or the assumptions are not met, then factor analysis will give erroneous results. Factor analysis has been used successfully where adequate understanding of the system permits good initial model formulations. PCA employs a mathematical transformation to the original data with no assumptions about the form of the covariance matrix. The objective of PCA is to determine linear combinations of the original variables and select a few that can be used to summarize the data set without losing much information.


title: Factor analysis

text: Fabrigar et al. (1999) address a number of reasons used to suggest that PCA is not equivalent to factor analysis:


title: Factor analysis

text: Factor analysis takes into account the random error that is inherent in measurement, whereas PCA fails to do so. This point is exemplified by Brown (2009), who indicated that, in respect to the correlation matrices involved in the calculations:


title: Factor analysis

text: For this reason, Brown (2009) recommends using factor analysis when theoretical ideas about relationships between variables exist, whereas PCA should be used if the goal of the researcher is to explore patterns in their data.


title: Factor analysis

text: Charles Spearman was the first psychologist to discuss common factor analysis and did so in his 1904 paper. It provided few details about his methods and was concerned with single-factor models. He discovered that school children's scores on a wide variety of seemingly unrelated subjects were positively correlated, which led him to postulate that a single general mental ability, or "g", underlies and shapes human cognitive performance.


title: Factor analysis

text: The initial development of common factor analysis with multiple factors was given by Louis Thurstone in two papers in the early 1930s, summarized in his 1935 book, "The Vector of Mind." Thurstone introduced several important factor analysis concepts, including communality, uniqueness, and rotation. He advocated for "simple structure", and developed methods of rotation that could be used as a way to achieve such structure.


title: Factor analysis

text: In Q methodology, Stephenson, a student of Spearman, distinguish between "R" factor analysis, oriented toward the study of inter-individual differences, and "Q" factor analysis oriented toward subjective intra-individual differences.


title: Factor analysis

text: Raymond Cattell was a strong advocate of factor analysis and psychometrics and used Thurstone's multi-factor theory to explain intelligence. Cattell also developed the scree test and similarity coefficients.


title: Factor analysis

text: Factor analysis is used to identify "factors" that explain a variety of results on different tests. For example, intelligence research found that people who get a high score on a test of verbal ability are also good on other tests that require verbal abilities. Researchers explained this by using factor analysis to isolate one factor, often called verbal intelligence, which represents the degree to which someone is able to solve problems involving verbal skills.


title: Factor analysis

text: Factor analysis in psychology is most often associated with intelligence research. However, it also has been used to find factors in a broad range of domains such as personality, attitudes, beliefs, etc. It is linked to psychometrics, as it can assess the validity of an instrument by finding if the instrument indeed measures the postulated factors.


title: Factor analysis

text: Factor analysis is a frequently used technique in cross-cultural research. It serves the purpose of extracting cultural dimensions. The best known cultural dimensions models are those elaborated by Geert Hofstede, Ronald Inglehart, Christian Welzel, Shalom Schwartz and Michael Minkov. A popular visualization is Inglehart and Welzel's cultural map of the world.


title: Factor analysis

text: The data collection stage is usually done by marketing research professionals. Survey questions ask the respondent to rate a product sample or descriptions of product concepts on a range of attributes. Anywhere from five to twenty attributes are chosen. They could include things like: ease of use, weight, accuracy, durability, colourfulness, price, or size. The attributes chosen will vary depending on the product being studied. The same question is asked about all the products in the study. The data for multiple products is coded and input into a statistical program such as R, SPSS, SAS, Stata, STATISTICA, JMP, and SYSTAT.


title: Factor analysis

text: The analysis will isolate the underlying factors that explain the data using a matrix of associations. Factor analysis is an interdependence technique. The complete set of interdependent relationships is examined. There is no specification of dependent variables, independent variables, or causality. Factor analysis assumes that all the rating data on different attributes can be reduced down to a few important dimensions. This reduction is possible because some attributes may be related to each other. The rating given to any one attribute is partially the result of the influence of other attributes. The statistical algorithm deconstructs the rating (called a raw score) into its various components and reconstructs the partial scores into underlying factor scores. The degree of correlation between the initial raw score and the final factor score is called a "factor loading".


title: Factor analysis

text: Factor analysis has also been widely used in physical sciences such as geochemistry, hydrochemistry, astrophysics and cosmology, as well as biological sciences, such as ecology, molecular biology, neuroscience and biochemistry.


title: Factor analysis

text: In groundwater quality management, it is important to relate the spatial distribution of different chemical


title: Factor analysis

text: parameters to different possible sources, which have different chemical signatures. For example, a sulfide mine is likely to be associated with high levels of acidity, dissolved sulfates and transition metals. These signatures can be identified as factors through R-mode factor analysis, and the location of possible sources can be suggested by contouring the factor scores.


title: Factor analysis

text: In geochemistry, different factors can correspond to different mineral associations, and thus to mineralisation.


title: Factor analysis

text: Factor analysis can be used for summarizing high-density oligonucleotide DNA microarrays data at probe level for Affymetrix GeneChips. In this case, the latent variable corresponds to the RNA concentration in a sample.


title: Girls Planet 999

text: Girls Planet 999: The Girls Saga (simply referred to as Girls Planet 999) was a South Korean reality competition show created by Mnet. It premiered on August 6, 2021 and was originally broadcast every Friday at 8:20 PM KST for the first eleven episodes until its finale on October 22, which was broadcast live at 8 PM KST. It was aired on the Mnet channel, IQIYI, AbemaTV, tvN Asia or YouTube depending on the viewer's region.


title: Girls Planet 999

text: A production by Mnet's parent company CJ E&M and its subsidiary Studio Take One, as well as in collaboration with game developer and publisher NCSoft, the aim of the competition was to debut a new 9-member K-pop girl group consisting of trainees and idols from China, Japan, and South Korea. Auditions for the competition were held from January to February 2021.


title: Girls Planet 999

text: Out of 13,000 applicants, 99 final contestants were selected. These 99 contestants were split equally into three groups; the -Group, -Group and the -Group.


title: Girls Planet 999

text: In the finale on October 22, 2021, which was broadcast live, the show announced the final 9 members who would debut as Kep1er.


title: Girls Planet 999

text: A second season named "Boys Planet" is expected to premiere in February 2023 featuring male trainees.


title: Girls Planet 999

text: The "planet" theme of the show was derived from a new collaboration between Mnet and NCSoft's new platform called Universe which is centered around K-pop. It allowed votes from other countries outside of the participating three, and also hosted other promotional content for the show.


title: Girls Planet 999

text: The show initially grouped the girls into groups of 3 which were called "cells." An entire cell of girls could be eliminated all at once, hence increasing the risk of elimination. To counteract this, the "Planet Top 9" is introduced. Contestants who are selected or voted to be the Planet Top 9 (designated P1 to P9) can reorganize cells to try and lower the chances of elimination. Cells were disbanded after the first elimination round. At the end of the competition, the top 9 most-voted contestants debuted regardless of nationality.


title: Girls Planet 999

text: The show, as well as its auditions, was first announced on January 11, 2021, through Mnet. Yeo Jin-goo was announced as the show's presenter on June 8, followed by the reveal of the mentors and the name of the show's opening theme later that same month. More promotional clips from the show were broadcast that month on Mnet.


title: Girls Planet 999

text: The show's premiere date of August 6, 2021, was confirmed through a teaser video released on July 6, 2021. Another teaser video showcasing the faces of the 99 contestants was released on July 8, along with a promotional poster.


title: Girls Planet 999

text: The theme song, “O.O.O (Over&Over&Over),” was released on July 12, 2021, accompanied by a performance by the Korean group with Kim Dayeon as Center. Another version of the performance featuring the Chinese group was released on July 14 with Shen Xiaoting as Center. The Japanese group's version was released on July 16 with Hikaru Ezaki as Center. The full version containing all three groups was released on July 29 during "M Countdown", preceded by the contestants' profiles which were released from July 17 to 19 at 10 AM KST for each group. More teasers were released in July and August 2021 leading up to the show's premiere.


title: Girls Planet 999

text: The show was available through Mnet in South Korea, iQIYI internationally, AbemaTV and Mnet Japan in Japan, tvN Asia in Southeast Asia, and YouTube in the rest of the world through Mnet's YouTube channel, Mnet K-POP.


title: Girls Planet 999

text: The series was presented by Yeo Jin-goo, dubbed as the "Planet Master." The rest of the mentors, also dubbed as "masters," were:


title: Girls Planet 999

text: There was a total of 99 contestants participating in the competition. 33 were Korean, and 33 consisted of Chinese, Taiwanese and Hongkongers, and the last 33 were Japanese.


title: Girls Planet 999

text: The English names of K-Group and C-Group contestants are presented in Eastern order in accordance with the official website while J-Group contestants' names are presented in Western order.


title: Girls Planet 999

text: The Planet Top 9 was either selected by the mentors (Episode 2) or voted by viewers of the show; those selected to be the Planet Top 9 in Episode 2 were given the ability to reshuffle and organize cells.


title: Girls Planet 999

text: Planet Pass was a vote by the mentors, in which eliminated contestants could be brought back to the show.


title: Girls Planet 999

text: The first two elimination rounds included a Planet Pass for one eliminated contestant from each group. The third elimination round included only one Planet Pass which could go to any eliminated contestant regardless of group.


title: Girls Planet 999

text: The third voting period took place from September 24, 2021 to October 9, 2021. Voters could only vote for one contestant from each group.


title: Girls Planet 999

text: The first round of the fourth voting period took from October 15, 2021 until 10AM KST on October 22, 2021.


title: Girls Planet 999

text: The second round was open during the finale live broadcast on October 22, 2021; all live votes were doubled.


title: Girls Planet 999

text: The finale was held and broadcast live on October 22, 2021. Yeo Jin-goo announced the newly formed girl group name to be Kep1er (Hangul: ).


title: Girls Planet 999

text: In the table below, turquoise numbers represent the lowest ratings and magenta numbers represent the highest ratings.


title: Girls Planet 999

text: Kep1er was supposed to debut on December 14, 2021 with the mini album "First Impact", but due to one of their staff members testing positive for COVID-19, their debut was delayed to January 3, 2022. The group's debut performance at the 2021 Mnet Asian Music Awards on December 11 was also cancelled as a result, as well as some members testing positive for COVID-19. The group officially debuted on January 3, 2022.


title: AirPlay

text: AirPlay is a proprietary wireless communication protocol stack/suite developed by Apple Inc. that allows streaming between devices of audio, video, device screens, and photos, together with related metadata. Originally implemented only in Apple's software and devices, it was called AirTunes and used for audio only. Apple has since licensed the AirPlay protocol stack as a third-party software component technology to manufacturers that build products compatible with Apple's devices.


title: AirPlay

text: In 2004, Apple introduced AirTunes as a new feature of iTunes 4.6. It allowed music streaming over a network to an AirPort Express, which was equipped with a 3.5 mm analog-digital audio jack for speakers or other audio devices. In 2010, Apple introduced a new iteration of the AirTunes technology, now called AirPlay, as part of iOS 4.2. It supported audio and now video streaming to the Apple TV, and later added screen-mirroring and eventually support for a broad range of 3rd-party AirPlay-compatible speakers and AV equipment.


title: AirPlay

text: Apple announced AirPlay 2 at its annual WWDC conference on June 5, 2017. It was scheduled for release along with iOS 11 in the third quarter of 2017, but was delayed until June 2018. Compared to the original version, AirPlay 2 improves buffering; adds streaming audio to stereo speakers; allows audio to be sent to multiple devices in different rooms; and control by Control Center, the Home app, or Siri, functionality that was only available previously using iTunes under macOS or Windows.


title: AirPlay

text: AirPlay sender devices include computers running iTunes, and iOS devices such as iPhones, iPods, and iPads running iOS 4.2 or greater, and devices can send AirPlay over Wi-Fi or ethernet. OS X Mountain Lion supports display mirroring via AirPlay on systems containing 2nd generation Intel Core processors or later.


title: AirPlay

text: In 2016, HTC released the "10", also known as "One M10", an Android phone with Apple AirPlay streaming.


title: AirPlay

text: As of iOS 4.3, third-party apps like ApowerMirror, AirServer, and Reflector may send compatible audio and video streams over AirPlay. The iTunes Remote app on iOS can be used to control media playback and select AirPlay streaming receivers for iTunes running on a Mac or PC.


title: AirPlay

text: As of macOS 10.14, there is no public API for third-party developers to integrate AirPlay 2 into their macOS apps. However, there are third-party streamers such as Airfoil. In May 2019, a third-party developer released a macOS app that can stream audio using AirPlay 2. The app includes a helper tool called "AirPlay Enabler" that uses code injection to bypass restrictions to the AirPlay 2 private API on macOS.


title: AirPlay

text: AirPlay receiver devices include Apple TV, HomePod, other third-party speakers and the discontinued AirPort Express, which included a combined analog and optical S/PDIF audio output connector. Compatible devices can receive AirPlay over wi-fi or ethernet. Some open-source projects have reverse-engineered the audio part of the protocol, enabling any computer to be turned into an AirPlay receiver for audio.


title: AirPlay

text: However, because not all third-party receivers implement Apple's DRM encryption, some media, such as iTunes Store's own rights-protected music (Apple's own "FairPlay" encryption), YouTube, and Netflix, cannot stream to those devices or software. On Apple TV, starting with firmware 6.0, the DRM scheme is enforced: devices without it cannot be used.


title: AirPlay

text: AirPlay wireless technology is integrated into speaker docks, AV receivers, and stereo systems from companies such as Bose, Yamaha, Philips, Marantz, Onkyo, Bowers & Wilkins, Pioneer, Sony, Sonos, McIntosh, Denon, and Bang & Olufsen. Song titles, artists, album names, elapsed and remaining time, and album artwork can appear on AirPlay-enabled speakers with graphical displays. Often these receivers are built to only support the audio component of AirPlay, much like AirTunes.


title: AirPlay

text: Bluetooth devices (headsets, speakers) that support the A2DP profile also appear as AirPlay receivers when paired with an iOS device, although Bluetooth is a device-to-device protocol that does not rely on a wireless network access point.


title: AirPlay

text: During the January 2019 Consumer Electronics Show (CES) in Las Vegas, television makers Samsung, LG, Vizio, and Sony announced they would be producing sets with built-in AirPlay 2 receiving capability. LG announced that television models that are AirPlay 2-enabled will include the 2019 OLED, NanoCell SM9X, UHD UM7X, and LG NanoCell SM8X models.


title: AirPlay

text: In September 2020, Roku added AirPlay 2 support as part of the 9.4 update on select 4K Roku devices. In April 2021, the 10.0 update added support for more Roku TVs and Players.


title: AirPlay

text: During WWDC 2021, Apple announced that macOS Monterey would include AirPlay receiver compatibility for compatible Macs.


title: AirPlay

text: AirPlay and AirTunes work over a local network, through either Wi-Fi or Ethernet. Originally, devices had to be connected to the same network, but since late 2017 devices can opt to use Wi-Fi Direct allowing devices to connect without a LAN.


title: AirPlay

text: The AirTunes part of the AirPlay protocol stack uses UDP for streaming audio and is based on the Real Time Streaming Protocol. The streams are transcoded using the Apple Lossless codec with 44100 Hz and 2 channels symmetrically encrypted with AES, requiring the receiver to have access to the appropriate key to decrypt the streams. The stream is buffered for approximately 2 seconds before playback begins, resulting in a small delay before audio is output after starting an AirPlay stream.


title: AirPlay

text: The protocol supports metadata packets that determine the final output volume on the receiving end. This makes it possible to always send audio data unprocessed at its original full volume, preventing sound quality deterioration due to reduction in bit depth and thus sound quality which would otherwise occur if changes in volume were made to the source stream before transmitting. It also makes possible the streaming of one source to multiple targets each with its own volume control.


title: AirPlay

text: The AirPort Express' streaming media capabilities use Apple's Remote Audio Output Protocol (RAOP), a proprietary variant of RTSP/RTP. Using WDS-bridging, the AirPort Express can allow AirPlay functionality (as well as Internet access, file and print sharing, etc.) across a larger distance in a mixed environment of wired and up to 10 wireless clients.


title: AirPlay

text: At WWDC 2011, Steve Jobs, then CEO of Apple Inc., announced AirPlay Mirroring as a feature in iOS 5 where the user can stream the screen from an iPad 2 to a HDTV wirelessly and securely without the need for cables.


title: AirPlay

text: AirPlay is a different technology from AirPlay Mirroring, as the former allows specific content formats to be streamed while the latter that allows the whole screen to be broadcast from a variety of iOS devices and iTunes to an Apple TV (2nd Gen or later). The exact composition of the protocols that AirPlay Mirroring uses have not yet fully been discovered, or reverse-engineered. However, an unofficial AirPlay protocol specification is available. Supported hardware (when using OS X Mountain Lion or later) includes any 2011 or later iMac, Mac mini, MacBook Air, MacBook Pro, or the Mac Pro (late 2013 or newer).


title: AirPlay

text: On April 8, 2011, James Laird reverse-engineered and released the private key used by the Apple AirPort Express to decrypt incoming audio streams. The release of this key means that third-party software and devices modified to use the key will be able to decrypt and play back or store AirPlay streams. Laird released ShairPort as an example of an audio-only software receiver implementation of AirPlay. Soon more followed and in 2012 the first AirPlay audio and video receiver for PC came with a product called AirServer.


title: AirPlay

text: An open-source AirPlay server known as RPiPlay is available for the Raspberry Pi and Desktop Linux operating systems.


title: Alex Iwobi

text: Alexander Chuka Iwobi ( ; born 3 May 1996) is a Nigerian professional footballer who plays as a midfielder for club Everton and the Nigeria national team.


title: Alex Iwobi

text: Iwobi began his career at Arsenal, making 149 appearances and scoring 15 goals, and winning the FA Cup in 2017, as well as scoring in the 2019 UEFA Europa League Final. In August 2019, he transferred to Everton for an initial £28 million fee.


title: Alex Iwobi

text: Iwobi represented England up to under-18 level. He made his senior international debut for Nigeria in October 2015, and was part of their squads at the FIFA World Cup in 2018 and the Africa Cup of Nations in 2019 and 2021, finishing third at the 2019 tournament.


title: Alex Iwobi

text: Iwobi was born in Lagos before moving to England at the age of four, following a brief stay in Turkey, and grew up in Newham, London. His maternal uncle is former professional footballer Jay-Jay Okocha.


title: Alex Iwobi

text: Iwobi joined Arsenal while still at primary school, in 2004, and was nearly released by the club at the age of 14 and again at the age of 16.


title: Alex Iwobi

text: He was first involved in a first-team match as an unused substitute in a League Cup match against West Bromwich Albion on 25 September 2013. He signed a long-term contract with Arsenal in October 2015.


title: Alex Iwobi

text: On 27 October 2015, Iwobi made his first-team debut for the club, starting in a 3–0 defeat to Sheffield Wednesday in the Round of 16 of the League Cup. He made his Premier League debut four days later in a 3–0 win against Swansea City at the Liberty Stadium, as a stoppage time substitute for Mesut Özil. Iwobi made his Champions League debut as an 85th-minute substitute in a 5–1 defeat against Bayern Munich. Iwobi started in the first team for the 2015–16 FA Cup 3rd and 4th round home wins against Sunderland and Burnley respectively.


title: Alex Iwobi

text: After getting a first Champions League start in a 3–1 away defeat to Barcelona, Iwobi went on to score two goals in his first two Premier League starts in wins against Everton, and Watford, respectively.


title: Alex Iwobi

text: In the following season, Iwobi changed his squad number from 45 to 17, after Alexis Sánchez took number 7 from the departing Tomáš Rosický. He went on to feature throughout Arsenal's victorious FA Cup campaign of 2016–17, winning 2–1 against Chelsea in the final. He achieved further success with Arsenal in the 2017 Community Shield, in which Arsenal beat Chelsea on penalties.


title: Alex Iwobi

text: In January 2018, a video was released that allegedly showed Iwobi at a late-night party 36 hours before a match. In May 2018, after Arsenal manager Arsène Wenger announced he would be leaving the club, Iwobi described him as an "inspiration" and stated it was sad but exciting.


title: Alex Iwobi

text: In January 2019, Iwobi was the subject of alleged racism from Indian actress Esha Gupta, an Arsenal ambassador.


title: Alex Iwobi

text: In May 2019 he scored Arsenal's only goal in the 2019 UEFA Europa League Final, in a 4–1 defeat to Chelsea.


title: Alex Iwobi

text: In July 2019, after the 2019 Africa Cup of Nations, he said he was looking forward to returning to club football with Arsenal.


title: Alex Iwobi

text: On 8 August 2019, Iwobi signed a five-year contract with Everton. According to the BBC, Arsenal received a fee of an initial £28 million, rising to £34 million with potential add-ons.


title: Alex Iwobi

text: Fifteen days after signing, Iwobi made his debut as a substitute for the final half-hour in place of Gylfi Sigurðsson in a 2–0 loss at Aston Villa. On 28 August in the second round of the EFL Cup, he scored his first Everton goal in a 4–2 win at Lincoln City. He scored his first league goal on 1 September in a 3–2 win over Wolverhampton Wanderers, and was one of two players singled out for praise by manager Marco Silva afterwards.


title: Alex Iwobi

text: Eligible to represent England or his birth country Nigeria, Iwobi started as a youth international for England, with whom he won the 2011 Victory Shield. Iwobi earned 11 caps for England at underage level, but went on to declare for Nigeria in 2015. He made his senior debut for the Super Eagles on 8 October, replacing Ahmed Musa in the 57th minute of a 2–0 friendly defeat to DR Congo in Visé, Belgium.


title: Alex Iwobi

text: He was selected by Nigeria for their 35-man provisional squad for the 2016 Summer Olympics. He was not a part of the 18-man final squad.


title: Alex Iwobi

text: In August 2017 Iwobi pulled out of Nigeria's squad for that month's World Cup qualifiers due to injury. In October 2017, Iwobi scored for Nigeria in a 1–0 win over Zambia to secure the Super Eagles a spot in the 2018 FIFA World Cup in Russia. He was named in Nigeria's 23-man squad for the competition and featured in all three games as the Super Eagles were knocked out in the group stage.


title: Alex Iwobi

text: In April 2019, he said he wanted to emulate his uncle Jay-Jay Okocha by winning the Africa Cup of Nations. He was included in Nigeria's squad for the 2019 tournament. At the tournament he said he would ignore the labelling of Nigeria as favourites. After the tournament he said he was looking forward to returning to club football with Arsenal.


title: Alex Iwobi

text: Iwobi was named in the Nigeria squad for the delayed 2021 Africa Cup of Nations in 2022. He was given a red card five minutes after coming on as a substitute in the knockout stage match against Tunisia, a match Nigeria lost 0-1.


title: Molten salt reactor

text: A molten salt reactor (MSR) is a class of nuclear fission reactor in which the primary nuclear reactor coolant and/or the fuel is a molten salt mixture. Only two MSRs have ever operated, both research reactors in the United States. The 1950's Aircraft Reactor Experiment was primarily motivated by the compact size that the technique offers, while the 1960's Molten-Salt Reactor Experiment aimed to prove the concept of a nuclear power plant which implements a thorium fuel cycle in a breeder reactor. Increased research into Generation IV reactor designs began to renew interest in the technology, with multiple nations having projects, and , China is on the verge of starting its TMSR-LF1 thorium MSR.


title: Molten salt reactor

text: MSRs are considered safer than conventional reactors because they operate with fuel already in a molten state, and in some designs in the event of an emergency, the fuel mixture is designed to drain from the core to a containment vessel where it will solidify in fuel drain tanks. This prevents the uncontrolled nuclear meltdown and associated hydrogen explosions (as in the Fukushima nuclear disaster) that are a risk in conventional (solid-fuel) reactors. They operate at or close to atmospheric pressure, rather than the 75-150 times atmospheric pressure of a typical light-water reactor (LWR), hence reducing the need for large, expensive reactor pressure vessels used in LWRs. Another advantage of MSRs is that the gaseous fission products (Xe and Kr) do not have much solubility in the fuel salt, and can be safely captured as they bubble out of the molten fuel, rather than increasing the pressure inside the fuel tubes over the life of the fuel, as happens in conventional solid-fuelled reactors. MSR's can also be refueled while operating (essentially online-nuclear reprocessing) while conventional reactors must be shut down for refueling (Pressure tube heavy water reactors like the CANDU or the Atucha-class PHWRs, and British-built Gas-cooled Reactors (Magnox, AGR) being notable exceptions).


title: Molten salt reactor

text: A further key characteristic of MSRs is operating temperatures of around , significantly higher than traditional LWRs at around , providing greater electricity-generation efficiency, the possibility of grid-storage facilities, economical hydrogen production, and, in some cases, process-heat opportunities. Relevant design challenges include the corrosivity of hot salts and the changing chemical composition of the salt as it is transmuted by the neutron flux in the reactor core.


title: Molten salt reactor

text: MSRs offer multiple advantages over conventional nuclear power plants, although for historical reasons they have not been deployed.


title: Molten salt reactor

text: MSRs, especially those with molten salt fuel, differ considerably from conventional reactors. Reactor core pressure can be low and the temperature much higher. In this respect an MSR is more similar to a liquid metal cooled reactor than to a conventional light water cooled reactor. MSRs are often planned as breeding reactors with a closed fuel cycle—as opposed to the once-through fuel currently used in U.S. nuclear reactors.


title: Molten salt reactor

text: Safety concepts rely on a negative temperature coefficient of reactivity and a large possible temperature rise to limit reactivity excursions. As an additional method for shutdown, a separate, passively cooled container below the reactor can be included. In case of problems, and for regular maintenance, the fuel is drained from the reactor. This stops the nuclear reaction and acts as a second cooling system. Neutron-producing accelerators have been proposed for some super-safe subcritical experimental designs.


title: Molten salt reactor

text: The temperatures of some proposed designs are high enough to produce process heat for hydrogen production or other chemical reactions. Because of this, they are included in the GEN-IV roadmap for further study.


title: Molten salt reactor

text: Molten-salt-cooled solid-fuel reactors are variously called "molten salt reactor system" in the Generation IV proposal, molten salt converter reactors (MSCR), advanced high-temperature reactors (AHTRs), or fluoride high-temperature reactors (FHR, preferred DOE designation).


title: Molten salt reactor

text: FHRs cannot reprocess fuel easily and have fuel rods that need to be fabricated and validated, requiring up to twenty years from project inception. FHR retains the safety and cost advantages of a low-pressure, high-temperature coolant, also shared by liquid metal cooled reactors. Notably, steam is not created in the core (as is present in BWRs), and no large, expensive steel pressure vessel (as required for PWRs). Since it can operate at high temperatures, the conversion of the heat to electricity can use an efficient, lightweight Brayton cycle gas turbine.


title: Molten salt reactor

text: Much of the current research on FHRs is focused on small, compact heat exchangers that reduce molten salt volumes and associated costs.