title: Inositol

text: Inositol has been repurposed as a possible augmentation strategy for depressive episodes in bipolar disorder. However, regardless of that, its link to serotonin, dopamine, and glutamate receptors, there have been very few trials, and several separate but similar experiments to gain evidence, that did not show a significant superiority to placebo in terms of efficacy for bipolar depression.


title: Inositol

text: Large doses of inositol have been studied for treatment of depression, but further study is needed to determine whether this is an effective treatment.


title: Inositol

text: Inositol has been found to have modest to moderate effects in patients with panic disorder or obsessive-compulsive disorder.


title: Inositol

text: High doses of inositol are sometimes used to treat trichotillomania (compulsive hair-pulling) and related disorders, but a small (N=38) double-blinded placebo-controlled trial did not find a statistically significant improvement with inositol.


title: Inositol

text: Inositol should not be routinely implemented for the management of preterm babies who have or are at a risk of infant respiratory distress syndrome (RDS). "Myo"-inositol helps prevent neural tube defects with particular efficacy in combination with folic acid.


title: Inositol

text: Inositol is considered a safe and effective treatment for polycystic ovary syndrome (PCOS). It works by increasing insulin sensitivity, which helps to improve ovarian function and reduce hyperandrogenism. It is also shown to reduce the risk of metabolic disease in people with PCOS. In addition, thanks to its role as FSH second messenger, "myo"-inositol is effective in restoring FSH/LH ratio and menstrual cycle regularization. "myo"-Inositol's role as FSH second messenger leads to a correct ovarian follicle maturation and consequently to a higher oocyte quality. Improving the oocyte quality in both women with or without PCOS, "myo"-inositol can be considered as a possible approach for increasing the chance of success in assisted reproductive technologies. In contrast, -"chiro"-inositol can impair oocyte quality in a dose-dependent manner. The high level of DCI seems to be related to elevated insulin levels retrieved in about 70% of PCOS women. In this regard, insulin stimulates the irreversible conversion of "myo"-inositol to -"chiro"-inositol causing a drastic reduction of "myo"-inositol. "myo"-Inositol depletion is particularly damaging to ovarian follicles because it is involved in FSH signaling, which is impaired due to "myo"-inositol depletion. Recent evidence reports a faster improvement of the metabolic and hormonal parameters when these two isomers are administered in their physiological ratio. The plasmatic ratio of "myo"-inositol and -"chiro"-inositol in healthy subjects is 40:1 of "myo"- and -"chiro"-inositol respectively. The use of the 40:1 ratio shows the same efficacy of "myo"-inositol alone but in a shorter time. In addition, the physiological ratio does not impair oocyte quality.


title: Inositol

text: The use of inositols in PCOS is gaining more importance, and an efficacy higher than 70% with a strong safety profile is reported. On the other hand, about 30% of patients could show as inositol-resistant. New evidence regarding PCOS aetiopathogenesis describes an alteration in the species and the quantity of each strain characterizing the normal gastrointestinal flora. This alteration could lead to chronic, low-level inflammation and malabsorption. A possible solution could be represented by the combination of "myo"-inositol and α-lactalbumin. This combination shows a synergic effect in increasing myo-inositol absorption. A recent study reported that the "myo"-inositol and α-lactalbumin combination is able to increase "myo"-inositol plasmatic content in inositol-resistant patients with a relative improvement of hormonal and metabolic parameters.


title: Inositol

text: Despite its antinutrient effect, phytic acid has potential uses in endodontics, adhesive, preventive, and regenerative dentistry, and in improving the characteristics and performance of dental materials.


title: Inositol

text: Inositol has been used as an adulterant or cutting agent for many illegal drugs, such as cocaine, methamphetamine, and sometimes heroin, probably because of its solubility, powdery texture, or reduced sweetness (50%) compared to more common sugars.


title: Inositol

text: "myo"-Inositol is naturally present in a variety of foods, although tables of food composition do not always distinguish between lecithin, the relatively bioavailable lipid form and the biounavailable phytate/phosphate form. Foods containing the highest concentrations of "myo"-inositol and its compounds include fruits, beans, grains, and nuts. Fruits in particular, especially oranges and cantaloupe, contain the highest amounts of "myo"-inositol. It is also present in beans, nuts, and grains, however, these contain large amounts of "myo"-inositol in the phytate form, which is not bioavailable without transformation by phytase enzymes. Bacillus subtilis, the microorganism which produces the fermented food natto, produces phytase enzymes that may convert phytic acid to a more bioavailable form of inositol polyphosphate in the gut. Additionally, "Bacteroides" species in the gut secrete vesicles containing an active enzyme which converts the phytate molecule into bioavailable phosphorus and inositol polyphosphate, which is an important signaling molecule in the human body.


title: Inositol

text: "myo"-Inositol can also be found as an ingredient in energy drinks, either in conjunction with or as a substitute for glucose, ostensibly to increase serotonin levels and alertness.


title: Inositol

text: In humans, myo-inositol is naturally made from glucose-6-phosphate through enzymatic dephosphorylation.


title: Cujo (film)

text: Cujo is a 1983 American horror film based on Stephen King's 1981 novel of the same name and directed by Lewis Teague. It was written by Don Carlos Dunaway and Barbara Turner (using the pen name Lauren Currier), and starring Dee Wallace, Daniel Hugh Kelly and Danny Pintauro.


title: Cujo (film)

text: The film follows a mother and her son who are trapped inside their car, while protecting themselves from a rabid St. Bernard.


title: Cujo (film)

text: Despite mixed reviews and modest box office receipts during its theatrical release, the film has gathered a cult following in the years since its release. It was released four months before "Christine", another Stephen King story released theatrically the same year.


title: Cujo (film)

text: Cujo, a friendly and easygoing St. Bernard, chases a wild rabbit and inserts his head into a cave, where a rabid bat bites him on the nose. Meanwhile, the Trenton family — advertising executive Vic, housewife Donna, and their sensitive young son Tad — take their car to the rural home of abusive mechanic Joe Camber for some repairs, where they meet Cujo, the Camber family's pet, and get along well with him.


title: Cujo (film)

text: Donna notices Cujo's bitten nose but thinks little of it. Later, Vic and Donna's marriage is tested when Vic learns that Donna is having an affair with her ex-boyfriend from high school, Steve Kemp, while Vic's advertising for a cereal commercial is failing. The early signs of Cujo's infection start to appear, including sensitivity to loud noises, and fraying temper producing soft growls, but no one notices these changes in his behavior. Charity and Brett, Joe's wife and son, leave the house for a week to visit Charity's sister Holly. On the morning of their departure, the furious stage of the infection begins to set in; though Cujo refrains from attacking Brett, he soon goes completely mad and kills the Cambers' alcoholic neighbor Gary Pervier. Shortly afterwards, Joe goes to Gary's house and finds him dead, then tries to call the authorities just before Cujo appears and attacks him.


title: Cujo (film)

text: Vic goes out of town on a business trip, as Donna and Tad return to the Cambers' house for more car repairs. Cujo attacks them, and they are forced to take shelter in their Ford Pinto. Donna tries to drive home, but the car's alternator dies and the two are trapped inside. The hot sun makes conditions nearly unbearable, and Donna realizes that she must do something before they both die from heatstroke or dehydration. However, attempts at escape are foiled by Cujo repeatedly attacking the car, breaking a window in the process, and even biting Donna. Vic returns home to rekindle his marriage, only to find Donna and Tad missing and his house vandalized by Kemp. He suspects the possessive Kemp of kidnapping, but the police realize his wife and son might be at the Cambers house.


title: Cujo (film)

text: The local sheriff, George Bannerman, arrives at the mechanics house and has a brief standoff; before he can draw his gun, Cujo kills him, knocking him off the catwalk in the barn and mauling him to death. Later, Donna attempts to get to the house to bring a dehydrated and overheated Tad water but is stopped by Cujo; she fights him off with a baseball bat until it breaks, leaving only a jagged handle. Cujo jumps at her and is impaled in the stomach by the broken bat. Donna takes the sheriff's gun and contemplates shooting him, but decides saving Tad is more important. After Donna revives Tad inside the kitchen, Cujo, still alive, breaks through the kitchen window and tries to attack Donna. However, Donna shoots Cujo dead before Vic arrives and reunites with his family.


title: Cujo (film)

text: The original director was Peter Medak, who left the project two days into filming, along with DOP Anthony B. Richmond. They were replaced by Lewis Teague and Jan de Bont respectively. Cujo was played by four St. Bernards, several mechanical dogs, and a black Labrador-Great Dane mix in a St. Bernard costume. In some shots, stuntman Gary Morgan played Cujo while wearing a large dog costume. Karl Miller was the trainer for the dogs in Cujo.


title: Cujo (film)

text: "Cujo" was a modest box office success for Warner Brothers. The film was released August 12, 1983, in the United States, opening in second place that weekend. It grossed a total of $21,156,152 domestically, making it the fourth-highest-grossing horror film of 1983 behind "Jaws 3-D", "Psycho II", and "".


title: Cujo (film)

text: Reviews from critics were mixed. Janet Maslin of "The New York Times" wrote the film was "by no means a horror classic, but it's suspenseful and scary". "Variety" panned it as "a dull, uneventful entry in the horror genre, a film virtually devoid of surprises or any original suspense". Gene Siskel of the "Chicago Tribune" gave the film one star out of four, calling it "one of the dumbest, flimsiest excuses for a movie I have ever seen". Roger Ebert called it "dreadful", and Linda Gross of the "Los Angeles Times" wrote that "no theater is air conditioned enough to justify watching this scary, gory and beastly movie".


title: Cujo (film)

text: Steve Jenkins of "The Monthly Film Bulletin" wrote that "for the most part "Cujo" works very effectively as a near reductio ad absurdum of the woman-in-peril-mode", but disliked that the film changed the ending from the book, thinking it made "absolutely no sense in terms of the film's logic". Author and film critic Leonard Maltin gave the film three out of a possible four stars, calling it "genuinely frightening" also writing: "Builds slowly but surely to [its] terrifying (but not gory) climax". Despite the mixed reception, Stephen King called the film "terrific" and named it one of his favorite adaptations.


title: Cujo (film)

text: On review aggregation website Rotten Tomatoes, it holds a 60% approval rating based on 43 reviews, with the website's consensus stating: ""Cujo" is artless work punctuated with moments of high canine gore and one wild Dee Wallace performance". On Metacritic, the film holds a 57/100 based on reviews from 8 critics, indicating "mixed or average reviews".


title: Cujo (film)

text: In 2015, Sunn Classic Pictures announced that it would develop another adaptation titled "C.U.J.O.", which stands for "Canine Unit Joint Operations". Nothing came of it after its announcement.


title: Amanda Cerny

text: Amanda Rachelle Cerny (born June 26, 1991) is an American Internet personality, actress, and model. She is best known for her YouTube channel and formerly her Vine profile on which she had over 4 million followers. She was "Playboy" magazine's Playmate of the Month for October 2011.


title: Amanda Cerny

text: At the age of 15, Cerny began working as a model at the time, as a hobby. She was featured in "Playboy" as the Playmate of the Month in the October 2011 edition. Cerny began posting content on Vine, and had over 4.6 million followers. She became a celebrity on YouTube, Instagram, Snapchat, Facebook, and Twitter.


title: Amanda Cerny

text: In August 2017, Cerny was named head of music streaming platform LiveXLive's newly formed Digital Talent Division.


title: Amanda Cerny

text: In June 2018 she was featured in the official video of Cardi B's "I Like It" alongside J Balvin and Bad Bunny. In January 2020, Cerny did a Punjabi music video "Where Baby Where" with Gippy Grewal.


title: Rick Danko

text: Richard Clare Danko (December 29, 1943 – December 10, 1999) was a Canadian musician, bassist, songwriter, and singer, best known as a founding member of the Band, for which he was inducted into the Rock and Roll Hall of Fame in 1994.


title: Rick Danko

text: During the 1960s, Danko performed as a member of the Hawks, backing Ronnie Hawkins and then Bob Dylan. Then, between 1968 and 1977, Danko and the Hawks, now called the Band, released seven studio albums before breaking up. Beginning with the group's reformation in 1983 and up until his death, Danko participated in the Band's partial reunion.


title: Rick Danko

text: Danko was born on December 29, 1943 in Blayney, Ontario, a farming community outside the town of Simcoe, the third of four sons in a musical family of Ukrainian descent. He grew up listening to live music at family gatherings and to country music, blues and R&B on the radio. He especially liked country music, and often his mother would let him stay up late to listen to the Grand Ole Opry on the radio.


title: Rick Danko

text: His musical influences included Hank Williams, the Carter Family and, later, Sam Cooke. He also drew inspiration from the music of his eldest brother, Junior. Danko's second-eldest brother, Dennis, was an accomplished songwriter, and his younger brother, Terry, also became a musician.


title: Rick Danko

text: He made his musical debut playing a four-string tenor banjo for his first-grade classmates, and while various sources differ slightly, all suggest he was headed to a professional career early. One report has him forming his first "Rick Danko Band" at age 12 or 13, another reference mentions that by age 14 he was putting on country & western shows with his brothers, Maurice Jr., Dennis and Terry, using various group names. It is also written that he started a band at that age with his eldest brother, Maurice Junior and a local high school teacher on drums. This trio performed country music and R & B at local dance halls, sometimes rented themselves, weddings, and other events. The group, "The Starlights", expanded to included accordion, second guitar and "a girl singer", expanded their repertoire to include polkas for newer European immigrants.


title: Rick Danko

text: By age 17, already a five-year music veteran and having already left the Simcoe Composite School and working by day as a butcher, Danko booked his band The Starlights as the opening act for Ronnie Hawkins.


title: Rick Danko

text: Hawkins invited Danko to join the Hawks as rhythm guitarist. Around this time, Hawks bassist Rebel Paine was fired by Hawkins, who, wasting no time, ordered Danko to learn to play the bass with help from other members in the band. By September 1960, he was Hawkins's bassist.


title: Rick Danko

text: In 1961, Danko with drummer Levon Helm backed guitarist Lenny Breau on several tracks recorded at Hallmark Studios in Toronto. These tracks are included on the 2003 release The Hallmark Sessions.


title: Rick Danko

text: Soon joined by pianist Richard Manuel and multi-instrumentalist Garth Hudson, the Hawks played with Hawkins through mid-1963. An altercation that year between Danko and Hawkins led Danko, Levon Helm, Robbie Robertson, Manuel, and Hudson to give two-weeks' notice in early 1964, and they parted ways with Hawkins on reasonably amicable terms. The group had been planning to break with Hawkins and continue together as a band without a frontman, as a team of equal members.


title: Rick Danko

text: Danko and the former Hawks initially performed as the Levon Helm Sextet with saxophonist Jerry Penfound. After Penfound left, they changed their name to The Canadian Squires, and finally to Levon and the Hawks. Playing a circuit that stretched geographically from Ontario to Arkansas, they became known as "the best damn bar band in the land."


title: Rick Danko

text: In August 1965, Mary Martin, an assistant to Bob Dylan's manager Albert Grossman, heard Levon and the Hawks perform. Grossman introduced the band's music to Dylan, who was impressed. The band was performing at Tony Mart's, a popular club in Somers Point, New Jersey, and Grossman's office called the club to speak with Levon and the group about touring with Dylan.


title: Rick Danko

text: Helm was not happy to be backing a "strummer" but reluctantly agreed, and the band became Dylan's backup group for a tour beginning in September. The tour, however, became too much for Helm, who departed in November. Through May 1966, Dylan and the remaining foursome (together with pick-up drummers, including the actor and musician Mickey Jones) traveled across the U.S., Australia, and Europe. After the final shows in Britain, Dylan retreated to his new home in Woodstock, New York, and the Hawks joined him there shortly thereafter.


title: Rick Danko

text: It was Danko who found the pink house on Parnassus Lane in Saugerties, New York, which became known as Big Pink. Danko, Hudson, and Manuel moved in, and Robertson lived nearby. The Band's musical sessions with Dylan took place in the basement of Big Pink, between June and October 1967, generating recordings that were officially released in 1975 as "The Basement Tapes". In October, the Hawks began demo recordings for their first album, with Helm rejoining the group in that month. Their manager, Albert Grossman, secured them a recording deal with Capitol Records in late 1967.


title: Rick Danko

text: From January to March 1968, the Band recorded their debut album, "Music from Big Pink", in recording studios in New York and Los Angeles. On this album, Danko sang lead vocal on three songs: "Caledonia Mission", "Long Black Veil" and "This Wheel's on Fire."


title: Rick Danko

text: Before the Band could promote the album by touring, Danko was severely injured in a car accident, breaking his neck and back in six places, which put him in traction for months. While he was in traction, Danko's girlfriend, Grace Seldner, informed him that she was pregnant, and he proposed from his hospital bed. When they married at the Church of the Holy Transfiguration of Christ-on-the-Mount in Woodstock, Danko was still in a neck brace. Rick and Grace divorced in October 1980.


title: Rick Danko

text: The Band finally made their concert debut at Bill Graham's Winterland Ballroom in San Francisco in April 1969. By this time, they were already hard at work on their eponymous second album. On that record, sometimes known as the Brown Album, Danko sang what would become two of his signature songs—and two of the group's best-loved classics: "When You Awake" and "Unfaithful Servant." Both songs exemplified Danko's talents as a lead singer and demonstrated his naturally plaintive voice.


title: Rick Danko

text: Danko is featured in the documentary film "Festival Express", about an all-star tour by train across Canada in 1970. On the train, he sings an impromptu version of "Ain't No More Cane" with Jerry Garcia and Janis Joplin.


title: Rick Danko

text: In an interview published in "Guitar Player", Danko cited bassists James Jamerson, Ron Carter, Edgar Willis, and Chuck Rainey as his musical influences. He eventually moved from the Fender Jazz Bass to an Ampeg fretless model and later a Gibson Ripper for "The Last Waltz".


title: Rick Danko

text: After the Band performed its farewell concert ("The Last Waltz") at Winterland in November 1976, Danko was offered a contract with Arista Records by Clive Davis, making him the first Band member to record a solo album. Issued in 1977, his self-titled début featured each of his former bandmates in addition to Ronnie Wood, Eric Clapton, Doug Sahm, Blondie Chaplin, and Danko's brother, Terry. The album was primarily recorded at the Band's California studio, Shangri-La. The poor sales of the album destined it for rarity status. After he recorded an unreleased follow-up album, Danko was dropped from Arista. The follow-up album was finally released as a part of "Cryin' Heart Blues" in 2005.


title: Rick Danko

text: In early 1979 Danko opened shows for Boz Scaggs. Also in 1979, Danko and Paul Butterfield toured together as the Danko/Butterfield Band. Among the songs they covered was "Sail On, Sailor", originally recorded by the Beach Boys, with Blondie Chaplin, who toured with Danko/Butterfield, on guitar and vocals. From 1983 to 1999, Danko alternated between a reformed version of the Band featuring Helm, Hudson, and guitarist Jim Weider (and, from 1983 to 1986, Manuel); a solo career; and collaborations including award-winning work with singer-songwriter Eric Andersen and Norway's Jonas Fjeld as Danko/Fjeld/Andersen.


title: Rick Danko

text: In 1984, Danko joined members of the Byrds, the Flying Burrito Brothers and others in a touring company called "The Byrds Twenty-Year Celebration." Several members of this band performed solo songs to start the show including Danko, who performed "Mystery Train". In 1989, he toured with Levon Helm and Garth Hudson as part of Ringo Starr's first All-Starr Band. On July 21, 1990, in Roger Waters's stage production of "The Wall Concert in Berlin, "Danko sang on the Pink Floyd songs "Comfortably Numb" and "Mother", the former with Van Morrison, Roger Waters, and Levon Helm, and the latter with Helm and Sinéad O'Connor. He recorded demos and made a number of appearances on albums by other artists throughout the 1980s and 1990s, and, in 1997, released "Rick Danko in Concert". Two years later, a third solo album ("Live on Breeze Hill") was released, and Danko was at work on a fourth ("Times Like These") at the time of his death.


title: Rick Danko

text: In the meantime, the Band (without Robbie Robertson and Richard Manuel) recorded three more albums, and Danko teamed with Fjeld and Andersen for two trio albums, "Danko/Fjeld/Andersen" in 1991 and "Ridin' on the Blinds" in 1994.


title: Rick Danko

text: Danko struggled with heroin addiction. On May 6, 1997, he was arrested in Japan for drug smuggling after his wife sent him heroin. Danko pleaded not guilty, but acknowledged having used heroin and stated that he would seek help if he were allowed to return to the United States. After spending 10 and one-half weeks in prison, Danko was released and given a suspended sentence.


title: Rick Danko

text: On December 10, 1999, days after the end of a brief tour of the Midwest that included two shows in the Chicago area and a final gig at the Ark in Ann Arbor, Michigan, Danko died of heart failure in his sleep at his home in Marbletown, New York. He was 55.


title: Rick Danko

text: He was survived by his second wife, Elizabeth (died 2013), whom he had married in 1989; a stepson, Justin, and a daughter, Lisa, from his first marriage. His son Eli, from Danko's first marriage, died in 1989 at age 18 from asphyxiation after heavy drinking while attending the State University of New York at Albany. Danko was buried next to Eli at Woodstock Cemetery, Woodstock, New York.


title: Rick Danko

text: For the April 2012 edition of "Bass Musician: Bass Magazine for Bass Players and the Bass Industry", Rob Collier wrote an article titled "How to Danko: A Lesson in the Style of Rick Danko".


title: Rick Danko

text: On the Irishtimes.com blogsite, Laurence Mackin wrote:Together with bass player Rick Danko, [Levon] Helm formed one of the finest rhythm sections to ever put a groove to a beat, and a partnership that formed the backbone of The Band. In Danko, he had the perfect complementary player, one of the finest bassists and one of the gentlest souls. His music was subtle, his instinct for just the right note unwavering – he could play one beat in four bars, but lord could he make it count. Their subtle, intense rhythmic conversation brought shape and distinction to the Band's music – it gave it heart and soul.


title: Rick Danko

text: The Drive-By Truckers' song "Danko/Manuel," written by Jason Isbell, was released on their album "The Dirty South" in 2004. Steve Forbert released "Wild as the Wind (A Tribute to Rick Danko)" on "Just Like There's Nothin' To It" in 2004. Martin Hagfors honored Danko on the Home Groan song "You Made a Difference" in 2000.


title: Rick Danko

text: A number of musical artists have cited Danko as an influence, including Elvis Costello, John Doe, Mumford & Sons, Lucinda Williams, Jay Farrar, Neko Case, Robbie Fulks, Cindy Cashdollar, Craig Finn of The Hold Steady, Chris Tomson of Vampire Weekend, Mike Watt, and Eric Clapton who said "Rick's singing has had a tremendous influence on me ... you have to be a great musician before you can sing like that."


title: Rick Danko

text: Danko used various basses throughout his career. He played a mid-sixties sunburst Fender Jazz Bass on the 1966 World Tour with Bob Dylan, and on the recording of "Music from Big Pink" and "The Band", as well as early live shows by The Band, including Woodstock and the Isle of Wight Festival. In late 1969, the Band was given some equipment by Ampeg, which included a fretted Ampeg AEB, a fretless Ampeg AMUB and an Ampeg "Baby Bass", a fiberglass-made electric upright bass. The fretless AMUB, modified with a Precision Bass pickup (see picture above, of Danko performing with the Band in Hamburg, 1971), was his bass of choice for the next years to come, and can be heard prominently on "Stage Fright" and "Cahoots", and was used live, as can be seen in the film Festival Express also in video footage included in the "Live at the Academy of Music 1971" release. This fretless bass was sold on eBay from a private collection in early 2012 for US$35,000.00. He was also seen performing with Fender Precision Basses and he also owned four Gibson Rippers, and would change out the pickups to experiment with different tones. Photos and video show him often playing a blonde one and also a sunburst, which was featured in "The Last Waltz".


title: Rick Danko

text: Throughout the 1990s, Danko played a custom-built hollow-body electric bass by luthier Mark Dan, with Alembic pickups, which he referred to as "One of the greatest basses that I've ever had". His other main bass throughout the 1990s was a red electric hollowbody bass from the Norwegian Workshop Guitar Company with two types of Alembic Pickups.


title: The Pirates: The Last Royal Treasure

text: The Pirates: The Last Royal Treasure () is a 2022 South Korean period adventure film directed by Kim Jeong-hoon and starring Han Hyo-joo and Kang Ha-neul. A spiritual sequel of 2014 film "The Pirates", the film is about adventures of pirates who gather in the sea and search for the royal treasures that have disappeared without a trace. It was released in IMAX format on January 26, 2022 coinciding with Korean New Year holiday.


title: The Pirates: The Last Royal Treasure

text: On box office, it became the first Korean film to register 1 million viewers in 2022 on 11th day of its release. It is currently the 10th highest-grossing Korean film of 2022, with a gross of US$10.31 million and 1.33 million admissions.


title: The Pirates: The Last Royal Treasure

text: In December 2018, the production of sequel to 2014 film "The Pirates" was announced. The film is directed by Kim Jeong-hoon, originally scheduled for the return of Kim Nam-gil and Son Ye-jin, and was expected to start filming in June 2019. In March 2019, Lee Kwang-soo joined the cast replacing Yoo Hae-jin, the member of original film cast. Due to various reasons and schedule conflicts of main leads, the filming was cancelled in May 2019. It took another ten months for producers to modify the script, cast the actors, and start the film with a new story.


title: The Pirates: The Last Royal Treasure

text: In March 2020 it was reported that Kang Ha-neul was considering to appear in the film. Han Hyo-joo reunited with Kang Ha-Neul, as she confirmed her casting in the film, marking her return to cinema after two years since "". In April 2020, Chae Soo-bin joined the cast of the film. In June 2020 the cast line-up of the film was completed and filming was planned to start in July.


title: The Pirates: The Last Royal Treasure

text: Filming began in July 2020, and concluded in January 2021. In September 2020, a staff member of the special effects team was tested positive for COVID-19, but other members were found negative. Previously the schedule was also delayed due to the rainy season.


title: The Pirates: The Last Royal Treasure

text: The film was originally scheduled to be released in the summer of 2021. The release date was pushed back to the Chuseok festival holidays, but was postponed due to the COVID-19 in South Korea. On October 29, 2021, it was announced that it will be theatrically released during the 2022 Korean New Year holiday. The film was released in IMAX format on January 26, 2022. On January 21, it was also released in 4DX, Superflex G, Superflex, Super 4D, and Dolby Atmos formats in 3 theatres.


title: The Pirates: The Last Royal Treasure

text: The film was released on 1703 screens on January 26, 2022. As per Korean Film Council (Kofic) integrated computer network, the film opened at no 1 place with 120,025 admissions on the Korean box office. It maintained its no 1 position at the Korean box office for consecutive 14 days after its release by gathering 1,122,499 cumulative admissions.


title: The Pirates: The Last Royal Treasure

text: The review aggregator website Rotten Tomatoes reported a 60% approval rating, based on 5 reviews with an average rating of 6/10.


title: The Pirates: The Last Royal Treasure

text: Kim Na-young writing for MK Sports termed the film as "spectacular adventures of pirates", and praised the performance of actors writing, "The actors' performances are also flawless." Kim found the story of the film "obvious" but not "boring". When comparing it with previous film Kim said, "It's the second story, which is not a continuation story, but another work." Concluding, Kim stated, "If you have seen the first movie, it will be fun to compare and watch, and if you see this film, it is fun to look for the first story again." Kim Hyun-soo of Cine21 comparing the film with previous version "The Pirates" (2014) wrote, "The harmonious combination of naval battles and intense ground battles that have increased so much is the exclusive highlight of this series. Praising performances of the cast and action sequences Kim stated, "The action of the three-way composition created by Kang Ha-neul, Han Hyo-joo, and Kwon Sang-woo is enough to attract attention."


title: The Pirates: The Last Royal Treasure

text: Johnny Loftus of Decider reviewing the series praised the performance of Han Hyo-joo writing "[she] is a revelation as the bold and courageous Captain Hae-rang." Concluding Loftus wrote, "Sword Fights on the decks of ships? Treasure maps? Mysterious islands shrouded by fearsome storms? "The Pirates: The Last Royal Treasure" has it all, and a charismatic cast to boot."


title: Kim Min-hee (actress, born 1982)

text: Kim Min-hee began modeling when she was in middle school, and soon appeared as a cover girl in teen magazines. In 1999, she was cast in the campus drama "School 2" as a rebellious high school girl, which launched her to stardom. She became a popular young star at barely 20 years old, appearing in TV dramas and movies. However, a string of poor acting performances brought her negative criticism. Critics and viewers disparagingly called her an "attractive but blank actress," more famous for being a fashion icon and actor Lee Jung-jae's then-girlfriend.


title: Kim Min-hee (actress, born 1982)

text: In 2006, after reading the synopsis of TV series "Goodbye Solo", Kim knew that she wanted the role of Mi-ri more than anything, saying "I was ready to do anything to play her." She begged renowned screenwriter Noh Hee-kyung to cast her, and though Noh turned her down five times, Kim would not give up, and her determination eventually convinced Noh to see her hidden potential. Vowing to start over from the bottom, Kim went through strict acting training which included basic vocal and respiratory exercises; she got a hold of the script before anyone else, and continued to analyze the role and practice every day. Kim said that until "Goodbye Solo", she hadn't been sure what to do with the rest of her life, but the drama made her feel that acting was her true calling, like she'd "finally opened up the first page of the textbook." She received good reviews for her performance, and despite the drama's low ratings, the role transformed her career.


title: Kim Min-hee (actress, born 1982)

text: Her succeeding movie roles helped solidify her career reinvention, beginning with 2008's "Hellcats" (also known by its Korean title "I Like It Hot" or "Some Like It Hot"), a light-hearted comedy that explored the lives and loves of three women at different stages of womanhood. Kim played an aspiring screenwriter in her twenties who's agonizing over her insecure career and shaky romance with a deadbeat musician boyfriend. Reviews praised her "compelling performance," and she later won Best Actress at the Baeksang Arts Awards and the Busan Film Critics Awards.


title: Kim Min-hee (actress, born 1982)

text: Kim then joined the all-star cast of "Actresses" (2009), a semi-improvisational mockumentary directed by E J-yong (whom she had previously worked with in "Asako in Ruby Shoes"). Set during a "Vogue Korea" photo shoot, Kim gets upset in the film over a remark by a staffer that men don't find skinny women like her attractive, as compared to her more voluptuous costar Kim Ok-bin. A supporting turn as a reporter in conspiracy film "Moby Dick" followed in 2011.


title: Kim Min-hee (actress, born 1982)

text: Kim further stretched the limits of her acting range in psychological thriller "Helpless" (2012), adapted from Miyabe Miyuki's novel "All She Was Worth" (in Japanese, "one-way train/fire chariot to hell"). She said she had absolute trust in director Byun Young-joo and never even checked the monitors, and Byun was likewise complimentary, saying, "I ended up adding more scenes for her to act because she was just exceptional. She knew what she was doing, and knew she was able to pull it off. She was rarely nervous throughout the production. She's got no fear and is always confident." Kim said the role gave her a chance to show what she was capable of as an actress, adding, "I feel differently about acting now. I often feel a tremendous sense of achievement and really enjoy doing this job." Displaying a striking screen presence as a mysterious girl who disappears without a trace while her bewildered fiancé discovers a trail of falsified information, Kim received several acting nominations and won Best Actress at the Buil Film Awards.


title: Kim Min-hee (actress, born 1982)

text: After her contract with Lee Byung-hun's agency BH Entertainment ended in late 2012, Kim signed with Management SOOP, which also handles the career of her friend Gong Hyo-jin.


title: Kim Min-hee (actress, born 1982)

text: In 2013, Kim again earned raves for her performance in "Very Ordinary Couple". Unlike the typical romantic comedy, the relationship drama told a more realistic story of an on-and-off couple of three years. During her acceptance speech as Best Actress at the 2013 Baeksang Arts Awards, Kim thanked her costar Lee Min-ki and director Roh Deok, who "helped shape (her) character Young on the screen." Action-noir "No Tears for the Dead" followed in 2014, in which she played a grieving woman who becomes a hitman's target.


title: Kim Min-hee (actress, born 1982)

text: Kim next starred in Hong Sang-soo's critically acclaimed film "Right Now, Wrong Then" (2015), which won her Best Actress at the Busan Film Critics Awards. Kim shot to international stardom for her performance in the award-winning film "The Handmaiden", Park Chan-wook's 2016 film adaptation of "Fingersmith" set in 1930s Korea. Park called her "the most coveted a-list actress at the moment."


title: Kim Min-hee (actress, born 1982)

text: In 2017, Kim became the first Korean actress to win the Silver Bear for Best Actress at the Berlin International Film Festival for her performance in the film "On the Beach at Night Alone". In 2018, she starred in "Grass" and "Hotel by the River".


title: Kim Min-hee (actress, born 1982)

text: Kim starred in "The Woman Who Ran" (2020) which won the Silver Bear for Best Director at the 70th Berlin International Film Festival. In 2020, "The New York Times" ranked Kim sixteenth on its list of "The 25 Greatest Actors of the 21st Century".


title: Kim Min-hee (actress, born 1982)

text: In June 2016, Kim was reported to be having an affair with Hong Sang-soo, the married director of the film "Right Now, Wrong Then", in which she starred as the lead actress in 2015. At the Seoul premiere of "On the Beach at Night Alone" in March 2017, Kim and Hong openly admitted their affair.


title: Kim Min-hee (actress, born 1982)

text: The controversy was allegedly the reason why Management SOOP decided not to renew Kim's management contract, which ended in early 2016. She also lost endorsement deals, including that of a cosmetics company.


title: Death of Gloria Ramirez

text: Gloria Cecilia Ramirez (January 11, 1963 – February 19, 1994) was a woman from Riverside, California, who was dubbed "the Toxic Lady" or "the Toxic Woman" by the media when several hospital workers became ill after exposure to her body and blood. She had been admitted to the emergency department while suffering from late-stage cervical cancer. While treating Ramirez, several hospital workers fainted and others experienced symptoms such as shortness of breath and muscle spasms. Five workers required hospitalization, one of whom remained in an intensive care unit for two weeks.


title: Death of Gloria Ramirez

text: Shortly after arriving at the hospital, Ramirez died from complications related to cancer. The incident was initially considered to be a case of mass hysteria. An investigation by Lawrence Livermore National Laboratory proposed that Ramirez had been self-administering dimethyl sulfoxide as a treatment for pain, which converted into dimethyl sulfate, an extremely poisonous and highly carcinogenic alkylating agent, via a series of chemical reactions in the emergency department. This theory has been endorsed by the Riverside Coroner's Office and published in the journal "Forensic Science International".


title: Death of Gloria Ramirez

text: About 8:15 p.m. on the evening of February 19, 1994, Ramirez, suffering from severe heart palpitations, was brought into the emergency department of Riverside General Hospital in Riverside, by paramedics. She was extremely confused and was suffering from tachycardia and Cheyne–Stokes respiration.


title: Death of Gloria Ramirez

text: The medical staff injected her with diazepam, midazolam, and lorazepam to sedate her. When it became clear that Ramirez was responding poorly to treatment, the staff tried to defibrillate her heart; at that point several people saw an oily sheen covering Ramirez's body, and some noticed a fruity, garlic-like odor that they thought was coming from her mouth. Registered nurse Susan Kane drew blood from Ramirez's arm and noticed an ammonia-like smell coming from the tube.


title: Death of Gloria Ramirez

text: She passed the tube to Julie Gorchynski, a medical resident, who noticed manila-colored particles floating in the blood. At this point, Kane fainted and was removed from the room. Shortly thereafter, Gorchynski began to feel nauseated. Complaining that she was lightheaded, she left the trauma room and sat at a nurse's desk. A staff member asked her if she was okay, but before she could respond she also fainted. Maureen Welch, a respiratory therapist who was assisting in the trauma room, was the third to pass out. The staff was then ordered to evacuate all emergency department patients to the parking lot outside the hospital. Overall, 23 people became ill and five were hospitalized. A skeleton crew stayed behind to stabilize Ramirez. At 8:50 p.m., after 45 minutes of CPR and defibrillation, Ramirez was pronounced dead from kidney failure related to her cancer.


title: Death of Gloria Ramirez

text: The county health department called in California's Department of Health and Human Services, which put two scientists, Drs. Ana Maria Osorio and Kirsten Waller, on the case. They interviewed 34 hospital staff who had been working in the emergency department on February 19. Using a standardized questionnaire, Osorio and Waller found that the people who had developed severe symptoms, such as loss of consciousness, shortness of breath, and muscle spasms, tended to have certain things in common. People who had worked within two feet of Ramirez and had handled her intravenous lines had been at high risk. But other factors that correlated with severe symptoms did not appear to match a scenario in which fumes had been released: the survey found that those afflicted tended to be women rather than men, and they all had normal blood tests after the exposure. They believed the hospital workers suffered from mass hysteria.


title: Death of Gloria Ramirez

text: Gorchynski denied that she had been affected by mass hysteria and pointed to her own medical history as evidence. After the exposure, she spent two weeks in the intensive care unit with breathing problems. She developed hepatitis and avascular necrosis in her knees. Riverside Coroner's Office contacted Lawrence Livermore National Laboratory to investigate the incident. Livermore Labs postulated that Ramirez had been using dimethyl sulfoxide (DMSO), a solvent used as a powerful degreaser, as a home remedy for pain. Users of this substance report that it has a garlic-like taste. Sold in gel form at hardware stores, it could also explain the greasy appearance of Ramirez's body. The Livermore scientists theorized that the DMSO in Ramirez's system might have built up owing to urinary blockage caused by her kidney failure. Oxygen administered by the paramedics would have combined with the DMSO to form dimethyl sulfone (DMSO). DMSO is known to crystallize at room temperature, and crystals were observed in some of Ramirez's drawn blood. Electric shocks administered during emergency defibrillation could have then converted the DMSO into dimethyl sulfate (DMSO), the highly toxic dimethyl ester of sulfuric acid, exposure to which could have caused some of the reported symptoms of the emergency department staff. The Livermore scientists postulated on "The New Detectives" that the change in temperature of the blood drawn, from the 98.6 °F (37 °C) of Ramirez's body to the 64 °F (18 °C) of the emergency department, may have contributed to its conversion from DMSO into DMSO. This, however, has not been confirmed.


title: Death of Gloria Ramirez

text: Two months after Ramirez died, her badly decomposed body was released for an independent autopsy and burial. The Riverside Coroner's Office hailed Livermore's DMSO conclusion as the probable cause of the hospital workers' symptoms, while her family disagreed. The Ramirez family's pathologist was unable to determine a cause of death because her heart was missing, her other organs were cross-contaminated with fecal matter, and her body was too badly decomposed. On April 20, 1994—ten weeks after her death—Ramirez was buried at Olivewood Memorial Park in Riverside.


title: Death of Gloria Ramirez

text: The possible chemical explanation for this incident by Patrick M. Grant of the Livermore Forensic Science Center is beginning to appear in basic forensic science textbooks. In Houck and Siegel's textbook, the authors state that, although some weaknesses exist, the postulated scenario is "the most scientific explanation to date" and that "beyond this theory, no credible explanation has ever been offered for the strange case of Gloria Ramirez."


title: Death of Gloria Ramirez

text: Grant's conclusions and speculations about the incident were evaluated by professional forensic scientists, chemists, and toxicologists, passed peer review in an accredited, refereed journal, and were published by "Forensic Science International". The first paper was technically detailed and contained two potential chemical reaction mechanisms that may possibly have formed dimethyl sulfate from dimethyl sulfoxide and dimethyl sulfone precursors. The second communication gave supplemental support for the postulated chemical scenario as well as insight into some of the sociology and vested interests inherent in the case.


title: Taylor's theorem

text: In calculus, Taylor's theorem gives an approximation of a "k"-times differentiable function around a given point by a polynomial of degree "k", called the "k"th-order Taylor polynomial. For a smooth function, the Taylor polynomial is the truncation at the order "k" of the Taylor series of the function. The first-order Taylor polynomial is the linear approximation of the function, and the second-order Taylor polynomial is often referred to as the quadratic approximation. There are several versions of Taylor's theorem, some giving explicit estimates of the approximation error of the function by its Taylor polynomial.


title: Taylor's theorem

text: Taylor's theorem is named after the mathematician Brook Taylor, who stated a version of it in 1715, although an earlier version of the result was already mentioned in 1671 by James Gregory.


title: Taylor's theorem

text: Taylor's theorem is taught in introductory-level calculus courses and is one of the central elementary tools in mathematical analysis. It gives simple arithmetic formulas to accurately compute values of many transcendental functions such as the exponential function and trigonometric functions.


title: Taylor's theorem

text: It is the starting point of the study of analytic functions, and is fundamental in various areas of mathematics, as well as in numerical analysis and mathematical physics. Taylor's theorem also generalizes to multivariate and vector valued functions.


title: Taylor's theorem

text: If a real-valued function "f"("x") is differentiable at the point "x" = "a", then it has a linear approximation near this point. This means that there exists a function "h"("x") such that


title: Taylor's theorem

text: is the linear approximation of "f"("x") for "x" near the point "a", whose graph is the tangent line to the graph y = "f"("x") at . The error in the approximation is:


title: Taylor's theorem

text: As "x" tends to "a," this error goes to zero much faster than formula_4, making formula_5 a useful approximation.


title: Taylor's theorem

text: For a better approximation to "f"("x"), we can fit a quadratic polynomial instead of a linear function:


title: Taylor's theorem

text: Instead of just matching one derivative of "f"("x") at "x" = "a", this polynomial has the same first and second derivatives, as is evident upon differentiation.


title: Taylor's theorem

text: Taylor's theorem ensures that the "quadratic approximation" is, in a sufficiently small neighborhood of "x =" "a", more accurate than the linear approximation. Specifically,


title: Taylor's theorem

text: which, given the limiting behavior of formula_9, goes to zero faster than formula_10 as "x" tends to "a".


title: Taylor's theorem

text: In general, the error in approximating a function by a polynomial of degree "k" will go to zero much faster than formula_11 as "x" tends to "a". However, there are functions, even infinitely differentiable ones, for which increasing the degree of the approximating polynomial does not increase the accuracy of approximation: we say such a function fails to be analytic at "x = a": it is not (locally) determined by its derivatives at this point.


title: Taylor's theorem

text: Taylor's theorem is of asymptotic nature: it only tells us that the error "R" in an approximation by a "k"-th order Taylor polynomial "P" tends to zero faster than any nonzero "k"-th degree polynomial as "x" → "a". It does not tell us how large the error is in any concrete neighborhood of the center of expansion, but for this purpose there are explicit formulas for the remainder term (given below) which are valid under some additional regularity assumptions on "f". These enhanced versions of Taylor's theorem typically lead to uniform estimates for the approximation error in a small neighborhood of the center of expansion, but the estimates do not necessarily hold for neighborhoods which are too large, even if the function "f" is analytic. In that situation one may have to select several Taylor polynomials with different centers of expansion to have reliable Taylor-approximations of the original function (see animation on the right.)


title: Taylor's theorem

text: of the function "f" at the point "a". The Taylor polynomial is the unique "asymptotic best fit" polynomial in the sense that if there exists a function and a "k"-th order polynomial "p" such that


title: Taylor's theorem

text: which is the approximation error when approximating "f" with its Taylor polynomial. Using the little-o notation, the statement in Taylor's theorem reads as


title: Taylor's theorem

text: Under stronger regularity assumptions on "f" there are several precise formulas for the remainder term "R" of the Taylor polynomial, the most common ones being the following.


title: Taylor's theorem

text: These refinements of Taylor's theorem are usually proved using the mean value theorem, whence the name. Additionally, notice that this is precisely the mean value theorem when "k = 0". Also other similar expressions can be found. For example, if "G"("t") is continuous on the closed interval and differentiable with a non-vanishing derivative on the open interval between "a" and "x", then


title: Taylor's theorem

text: for some number "ξ" between "a" and "x". This version covers the Lagrange and Cauchy forms of the remainder as special cases, and is proved below using Cauchy's mean value theorem. The Lagrange form is obtained by taking formula_17 and the Cauchy form is obtained by taking formula_18.


title: Taylor's theorem

text: The statement for the integral form of the remainder is more advanced than the previous ones, and requires understanding of Lebesgue integration theory for the full generality. However, it holds also in the sense of Riemann integral provided the ("k" + 1)th derivative of "f" is continuous on the closed interval ["a","x"].


title: Taylor's theorem

text: Due to absolute continuity of "f" on the closed interval between "a" and "x", its derivative "f" exists as an "L"-function, and the result can be proven by a formal calculation using fundamental theorem of calculus and integration by parts.


title: Taylor's theorem

text: It is often useful in practice to be able to estimate the remainder term appearing in the Taylor approximation, rather than having an exact formula for it. Suppose that "f" is -times continuously differentiable in an interval "I" containing "a". Suppose that there are real constants "q" and "Q" such that


title: Taylor's theorem

text: if , and a similar estimate if . This is a simple consequence of the Lagrange form of the remainder. In particular, if


title: Taylor's theorem

text: For example, the third-order Taylor polynomial of a smooth function "f": R → R is, denoting x − a = v,


title: Taylor's theorem

text: The proof here is based on repeated application of L'Hôpital's rule. Note that, for each , formula_28. Hence each of the first "k"−1 derivatives of the numerator in formula_29 vanishes at formula_30, and the same is true of the denominator. Also, since the condition that the function "f" be "k" times differentiable at a point requires differentiability up to order "k"−1 in a neighborhood of said point (this is true, because differentiability requires a function to be defined in a whole neighborhood of a point), the numerator and its "k" − 2 derivatives are differentiable in a neighborhood of "a". Clearly, the denominator also satisfies said condition, and additionally, doesn't vanish unless "x"="a", therefore all conditions necessary for L'Hopital's rule are fulfilled, and its use is justified. So


title: Taylor's theorem

text: Let formula_39 and formula_40 be continuous functions on formula_41. Since formula_42 so we can work with the interval formula_43. Let formula_39 and formula_40 be differentiable on formula_46. Assume formula_47 for all formula_48.


title: Taylor's theorem

text: Let "G" be any real-valued function, continuous on the closed interval between "a" and "x" and differentiable with a non-vanishing derivative on the open interval between "a" and "x", and define


title: Taylor's theorem

text: for some ξ on the open interval between "a" and "x". Note that here the numerator is exactly the remainder of the Taylor polynomial for "f"("x"). Compute


title: Taylor's theorem

text: This is the form of the remainder term mentioned after the actual statement of Taylor's theorem with remainder in the mean value form.


title: Taylor's theorem

text: The Lagrange form of the remainder is found by choosing formula_77 and the Cauchy form by choosing formula_78.


title: Taylor's theorem

text: but the requirements for "f" needed for the use of mean value theorem are too strong, if one aims to prove the claim in the case that "f" is only absolutely continuous. However, if one uses Riemann integral instead of Lebesgue integral, the assumptions cannot be weakened.


title: Taylor's theorem

text: Due to absolute continuity of "f" on the closed interval between "a" and "x" its derivative "f" exists as an "L"-function, and we can use fundamental theorem of calculus and integration by parts. This same proof applies for the Riemann integral assuming that "f" is continuous on the closed interval and differentiable on the open interval between "a" and "x", and this leads to the same result than using the mean value theorem.


title: Taylor's theorem

text: which is exactly Taylor's theorem with remainder in the integral form in the case "k"=1. The general statement is proved using induction. Suppose that


title: Taylor's theorem

text: Substituting this into the formula shows that if it holds for the value "k", it must also hold for the value "k" + 1. Therefore, since it holds for "k" = 1, it must hold for every positive integer "k".


title: Taylor's theorem

text: We prove the special case, where "f" : R → R has continuous partial derivatives up to the order "k"+1 in some closed ball "B" with center a. The strategy of the proof is to apply the one-variable case of Taylor's theorem to the restriction of "f" to the line segment adjoining x and a. Parametrize the line segment between a and x by u("t") = We apply the one-variable version of Taylor's theorem to the function :


title: Theoretical physics

text: Theoretical physics is a branch of physics that employs mathematical models and abstractions of physical objects and systems to rationalize, explain and predict natural phenomena. This is in contrast to experimental physics, which uses experimental tools to probe these phenomena.


title: Theoretical physics

text: The advancement of science generally depends on the interplay between experimental studies and theory. In some cases, theoretical physics adheres to standards of mathematical rigour while giving little weight to experiments and observations. For example, while developing special relativity, Albert Einstein was concerned with the Lorentz transformation which left Maxwell's equations invariant, but was apparently uninterested in the Michelson–Morley experiment on Earth's drift through a luminiferous aether. Conversely, Einstein was awarded the Nobel Prize for explaining the photoelectric effect, previously an experimental result lacking a theoretical formulation.


title: Theoretical physics

text: A physical theory is a model of physical events. It is judged by the extent to which its predictions agree with empirical observations. The quality of a physical theory is also judged on its ability to make new predictions which can be verified by new observations. A physical theory differs from a mathematical theorem in that while both are based on some form of axioms, judgment of mathematical applicability is not based on agreement with any experimental results. A physical theory similarly differs from a mathematical theory, in the sense that the word "theory" has a different meaning in mathematical terms.


title: Theoretical physics

text: A physical theory involves one or more relationships between various measurable quantities. Archimedes realized that a ship floats by displacing its mass of water, Pythagoras understood the relation between the length of a vibrating string and the musical tone it produces. Other examples include entropy as a measure of the uncertainty regarding the positions and motions of unseen particles and the quantum mechanical idea that (action and) energy are not continuously variable.


title: Theoretical physics

text: Theoretical physics consists of several different approaches. In this regard, theoretical particle physics forms a good example. For instance: "phenomenologists" might employ (semi-) empirical formulas and heuristics to agree with experimental results, often without deep physical understanding. "Modelers" (also called "model-builders") often appear much like phenomenologists, but try to model speculative theories that have certain desirable features (rather than on experimental data), or apply the techniques of mathematical modeling to physics problems. Some attempt to create approximate theories, called "effective theories", because fully developed theories may be regarded as unsolvable or too complicated. Other theorists may try to unify, formalise, reinterpret or generalise extant theories, or create completely new ones altogether. Sometimes the vision provided by pure mathematical systems can provide clues to how a physical system might be modeled; e.g., the notion, due to Riemann and others, that space itself might be curved. Theoretical problems that need computational investigation are often the concern of computational physics.


title: Theoretical physics

text: Theoretical advances may consist in setting aside old, incorrect paradigms (e.g., aether theory of light propagation, caloric theory of heat, burning consisting of evolving phlogiston, or astronomical bodies revolving around the Earth) or may be an alternative model that provides answers that are more accurate or that can be more widely applied. In the latter case, a correspondence principle will be required to recover the previously known result. Sometimes though, advances may proceed along different paths. For example, an essentially correct theory may need some conceptual or factual revisions; atomic theory, first postulated millennia ago (by several thinkers in Greece and India) and the two-fluid theory of electricity are two cases in this point. However, an exception to all the above is the wave–particle duality, a theory combining aspects of different, opposing models via the Bohr complementarity principle.


title: Theoretical physics

text: Physical theories become accepted if they are able to make correct predictions and no (or few) incorrect ones. The theory should have, at least as a secondary objective, a certain economy and elegance (compare to mathematical beauty), a notion sometimes called "Occam's razor" after the 13th-century English philosopher William of Occam (or Ockham), in which the simpler of two theories that describe the same matter just as adequately is preferred (but conceptual simplicity may mean mathematical complexity). They are also more likely to be accepted if they connect a wide range of phenomena. Testing the consequences of a theory is part of the scientific method.


title: Theoretical physics

text: Physical theories can be grouped into three categories: "mainstream theories", "proposed theories" and "fringe theories".


title: Theoretical physics

text: Theoretical physics began at least 2,300 years ago, under the Pre-socratic philosophy, and continued by Plato and Aristotle, whose views held sway for a millennium. During the rise of medieval universities, the only acknowledged intellectual disciplines were the seven liberal arts of the "Trivium" like grammar, logic, and rhetoric and of the "Quadrivium" like arithmetic, geometry, music and astronomy. During the Middle Ages and Renaissance, the concept of experimental science, the counterpoint to theory, began with scholars such as Ibn al-Haytham and Francis Bacon. As the Scientific Revolution gathered pace, the concepts of matter, energy, space, time and causality slowly began to acquire the form we know today, and other sciences spun off from the rubric of natural philosophy. Thus began the modern era of theory with the Copernican paradigm shift in astronomy, soon followed by Johannes Kepler's expressions for planetary orbits, which summarized the meticulous observations of Tycho Brahe; the works of these men (alongside Galileo's) can perhaps be considered to constitute the Scientific Revolution.


title: Theoretical physics

text: The great push toward the modern concept of explanation started with Galileo, one of the few physicists who was both a consummate theoretician and a great experimentalist. The analytic geometry and mechanics of Descartes were incorporated into the calculus and mechanics of Isaac Newton, another theoretician/experimentalist of the highest order, writing Principia Mathematica. In it contained a grand synthesis of the work of Copernicus, Galileo and Kepler; as well as Newton's theories of mechanics and gravitation, which held sway as worldviews until the early 20th century. Simultaneously, progress was also made in optics (in particular colour theory and the ancient science of geometrical optics), courtesy of Newton, Descartes and the Dutchmen Snell and Huygens. In the 18th and 19th centuries Joseph-Louis Lagrange, Leonhard Euler and William Rowan Hamilton would extend the theory of classical mechanics considerably. They picked up the interactive intertwining of mathematics and physics begun two millennia earlier by Pythagoras.


title: Theoretical physics

text: Among the great conceptual achievements of the 19th and 20th centuries were the consolidation of the idea of energy (as well as its global conservation) by the inclusion of heat, electricity and magnetism, and then light. The laws of thermodynamics, and most importantly the introduction of the singular concept of entropy began to provide a macroscopic explanation for the properties of matter. Statistical mechanics (followed by statistical physics and Quantum statistical mechanics) emerged as an offshoot of thermodynamics late in the 19th century. Another important event in the 19th century was the discovery of electromagnetic theory, unifying the previously separate phenomena of electricity, magnetism and light.


title: Theoretical physics

text: The pillars of modern physics, and perhaps the most revolutionary theories in the history of physics, have been relativity theory and quantum mechanics. Newtonian mechanics was subsumed under special relativity and Newton's gravity was given a kinematic explanation by general relativity. Quantum mechanics led to an understanding of blackbody radiation (which indeed, was an original motivation for the theory) and of anomalies in the specific heats of solids — and finally to an understanding of the internal structures of atoms and molecules. Quantum mechanics soon gave way to the formulation of quantum field theory (QFT), begun in the late 1920s. In the aftermath of World War 2, more progress brought much renewed interest in QFT, which had since the early efforts, stagnated. The same period also saw fresh attacks on the problems of superconductivity and phase transitions, as well as the first applications of QFT in the area of theoretical condensed matter. The 1960s and 70s saw the formulation of the Standard model of particle physics using QFT and progress in condensed matter physics (theoretical foundations of superconductivity and critical phenomena, among others), in parallel to the applications of relativity to problems in astronomy and cosmology respectively.


title: Theoretical physics

text: All of these achievements depended on the theoretical physics as a moving force both to suggest experiments and to consolidate results — often by ingenious application of existing mathematics, or, as in the case of Descartes and Newton (with Leibniz), by inventing new mathematics. Fourier's studies of heat conduction led to a new branch of mathematics: infinite, orthogonal series.


title: Theoretical physics

text: Modern theoretical physics attempts to unify theories and explain phenomena in further attempts to understand the Universe, from the cosmological to the elementary particle scale. Where experimentation cannot be done, theoretical physics still tries to advance through the use of mathematical models.


title: Theoretical physics

text: Mainstream theories (sometimes referred to as "central theories") are the body of knowledge of both factual and scientific views and possess a usual scientific quality of the tests of repeatability, consistency with existing well-established science and experimentation. There do exist mainstream theories that are generally accepted theories based solely upon their effects explaining a wide variety of data, although the detection, explanation, and possible composition are subjects of debate.


title: Theoretical physics

text: The proposed theories of physics are usually relatively new theories which deal with the study of physics which include scientific approaches, means for determining the validity of models and new types of reasoning used to arrive at the theory. However, some proposed theories include theories that have been around for decades and have eluded methods of discovery and testing. Proposed theories can include fringe theories in the process of becoming established (and, sometimes, gaining wider acceptance). Proposed theories usually have not been tested. In addition to the theories like those listed below, there are also different interpretations of quantum mechanics, which may or may not be considered different theories since it is debatable whether they yield different predictions for physical experiments, even in principle. For example, AdS/CFT correspondence, Chern–Simons theory, graviton, magnetic monopole, string theory, theory of everything.


title: Theoretical physics

text: Fringe theories include any new area of scientific endeavor in the process of becoming established and some proposed theories. It can include speculative sciences. This includes physics fields and physical theories presented in accordance with known evidence, and a body of associated predictions have been made according to that theory.


title: Theoretical physics

text: Some fringe theories go on to become a widely accepted part of physics. Other fringe theories end up being disproven. Some fringe theories are a form of protoscience and others are a form of pseudoscience. The falsification of the original theory sometimes leads to reformulation of the theory.


title: Theoretical physics

text: "Thought" experiments are situations created in one's mind, asking a question akin to "suppose you are in this situation, assuming such is true, what would follow?". They are usually created to investigate phenomena that are not readily experienced in every-day situations. Famous examples of such thought experiments are Schrödinger's cat, the EPR thought experiment, simple illustrations of time dilation, and so on. These usually lead to real experiments designed to verify that the conclusion (and therefore the assumptions) of the thought experiments are correct. The EPR thought experiment led to the Bell inequalities, which were then tested to various degrees of rigor, leading to the acceptance of the current formulation of quantum mechanics and probabilism as a working hypothesis.


title: I²C

text: IC (Inter-Integrated Circuit, ), alternatively known as I2C or IIC, is a synchronous, multi-controller/multi-target (master/slave), packet switched, single-ended, serial communication bus invented in 1982 by Philips Semiconductors. It is widely used for attaching lower-speed peripheral ICs to processors and microcontrollers in short-distance, intra-board communication.


title: I²C

text: Several competitors, such as Siemens, NEC, Texas Instruments, STMicroelectronics, Motorola, Nordic Semiconductor and Intersil, have introduced compatible IC products to the market since the mid-1990s.


title: I²C

text: System Management Bus (SMBus), defined by Intel in 1995, is a subset of IC, defining a stricter usage. One purpose of SMBus is to promote robustness and interoperability. Accordingly, modern IC systems incorporate some policies and rules from SMBus, sometimes supporting both IC and SMBus, requiring only minimal reconfiguration either by commanding or output pin use.


title: I²C

text: IC is appropriate for peripherals where simplicity and low manufacturing cost are more important than speed. Common applications of the IC bus are:


title: I²C

text: A particular strength of IC is the capability of a microcontroller to control a network of device chips with just two general-purpose I/O pins and software. Many other bus technologies used in similar applications, such as Serial Peripheral Interface Bus (SPI), require more pins and signals to connect multiple devices.


title: I²C

text: IC uses only two bidirectional open-collector or open-drain lines: serial data line (SDA) and serial clock line (SCL), pulled up with resistors. Typical voltages used are +5 V or +3.3 V, although systems with other voltages are permitted.


title: I²C

text: The IC reference design has a 7-bit address space, with a rarely used 10-bit extension. Common IC bus speeds are the 100 kbit/s "standard mode" and the 400 kbit/s "fast mode". There is also a 10 kbit/s "low-speed mode", but arbitrarily low clock frequencies are also allowed. Later revisions of IC can host more nodes and run at faster speeds (400 kbit/s "fast mode", 1 Mbit/s "fast mode plus", 3.4 Mbit/s "high-speed mode", and 5 Mbit/s "ultra-fast mode"). These speeds are more widely used on embedded systems than on PCs.


title: I²C

text: Note that the bit rates are quoted for the transfers between controller (master) and target (slave) without clock stretching or other hardware overhead. Protocol overheads include a target address and perhaps a register address within the target device, as well as per-byte ACK/NACK bits. Thus the actual transfer rate of user data is lower than those peak bit rates alone would imply. For example, if each interaction with a target inefficiently allows only 1 byte of data to be transferred, the data rate will be less than half the peak bit rate.


title: I²C

text: The number of nodes which can exist on a given IC bus is limited by the address space and also by the total bus capacitance of 400 pF, which restricts practical communication distances to a few meters. The relatively high impedance and low noise immunity requires a common ground potential, which again restricts practical use to communication within the same PC board or small system of boards.


title: I²C

text: The aforementioned reference design is a bus with a clock (SCL) and data (SDA) lines with 7-bit addressing. The bus has two roles for nodes,


title: I²C

text: The bus is a multi-controller bus, which means that any number of controller nodes can be present. Additionally, controller and target roles may be changed between messages (after a STOP is sent).


title: I²C

text: There may be four potential modes of operation for a given bus device, although most devices only use a single role and its two modes:


title: I²C

text: In addition to 0 and 1 data bits, the IC bus allows special START and STOP signals which act as message delimiters and are distinct from the data bits. (This is in contrast to the start bits and stop bits used in asynchronous serial communication, which are distinguished from data bits only by their timing.)


title: I²C

text: The controller is initially in controller transmit mode by sending a START followed by the 7-bit address of the target it wishes to communicate with, which is finally followed by a single bit representing whether it wishes to write (0) to or read (1) from the target.


title: I²C

text: If the target exists on the bus then it will respond with an ACK bit (active low for acknowledged) for that address. The controller then continues in either transmit or receive mode (according to the read/write bit it sent), and the target continues in the complementary mode (receive or transmit, respectively).


title: I²C

text: The address and the data bytes are sent most significant bit first. The start condition is indicated by a high-to-low transition of SDA with SCL high; the stop condition is indicated by a low-to-high transition of SDA with SCL high. All other transitions of SDA take place with SCL low.


title: I²C

text: If the controller wishes to write to the target, then it repeatedly sends a byte with the target sending an ACK bit. (In this situation, the controller is in controller transmit mode, and the target is in target receive mode.)


title: I²C

text: If the controller wishes to read from the target, then it repeatedly receives a byte from the target, the controller sending an ACK bit after every byte except the last one. (In this situation, the controller is in controller receive mode, and the target is in target transmit mode.)


title: I²C

text: An IC transaction may consist of multiple messages. The controller terminates a message with a STOP condition if this is the end of the transaction or it may send another START condition to retain control of the bus for another message (a "combined format" transaction).


title: I²C

text: In a combined transaction, each read or write begins with a START and the target address. The START conditions after the first are also called "repeated START" bits. Repeated STARTs are not preceded by STOP conditions, which is how targets know that the next message is part of the same transaction.


title: I²C

text: Pure IC systems support arbitrary message structures. SMBus is restricted to nine of those structures, such as "read word N" and "write word N", involving a single target. PMBus extends SMBus with a "Group" protocol, allowing multiple such SMBus transactions to be sent in one combined message. The terminating STOP indicates when those grouped actions should take effect. For example, one PMBus operation might reconfigure three power supplies (using three different IC target addresses), and their new configurations would take effect at the same time: when they receive that STOP.


title: I²C

text: With only a few exceptions, neither IC nor SMBus define message semantics, such as the meaning of data bytes in messages. Message semantics are otherwise product-specific. Those exceptions include messages addressed to the IC "general call" address (0x00) or to the SMBus "Alert Response Address"; and messages involved in the SMBus "Address Resolution Protocol" (ARP) for dynamic address allocation and management.


title: I²C

text: In practice, most targets adopt request-response control models, where one or more bytes following a write command are treated as a command or address. Those bytes determine how subsequent written bytes are treated or how the target responds on subsequent reads. Most SMBus operations involve single-byte commands.


title: I²C

text: One specific example is the 24C32 type EEPROM, which uses two request bytes that are called Address High and Address Low. (Accordingly, these EEPROMs are not usable by pure SMBus hosts, which support only single-byte commands or addresses.) These bytes are used for addressing bytes within the 32 kbit (or 4 kB) EEPROM address space. The same two-byte addressing is also used by larger EEPROMs, like the 24C512 which stores 512 kbits (or 64 kB). Writing data to and reading from these EEPROMs uses a simple protocol: the address is written, and then data is transferred until the end of the message. The data transfer part of the protocol can cause trouble on the SMBus, since the data bytes are not preceded by a count, and more than 32 bytes can be transferred at once. IC EEPROMs smaller than 32 kbit, like the 2 kbit 24C02, are often used on the SMBus with inefficient single-byte data transfers to overcome this problem.


title: I²C

text: A single message writes to the EEPROM. After the START, the controller sends the chip's bus address with the direction bit clear ("write"), then sends the two-byte address of data within the EEPROM and then sends data bytes to be written starting at that address, followed by a STOP. When writing multiple bytes, all the bytes must be in the same 32-byte page. While it is busy saving those bytes to memory, the EEPROM will not respond to further IC requests. (That is another incompatibility with SMBus: SMBus devices must always respond to their bus addresses.)


title: I²C

text: To read starting at a particular address in the EEPROM, a combined message is used. After a START, the controller first writes that chip's bus address with the direction bit clear ("write") and then the two bytes of EEPROM data address. It then sends a (repeated) START and the EEPROM's bus address with the direction bit set ("read"). The EEPROM will then respond with the data bytes beginning at the specified EEPROM data address — a combined message: first a write, then a read. The controller issues an ACK after each read byte except the last byte, and then issues a STOP. The EEPROM increments the address after each data byte transferred; multi-byte reads can retrieve the entire contents of the EEPROM using one combined message.


title: I²C

text: At the physical layer, both SCL and SDA lines are an open-drain (MOSFET) or open-collector (BJT) bus design, thus a pull-up resistor is needed for each line. A logic "0" is output by pulling the line to ground, and a logic "1" is output by letting the line float (output high impedance) so that the pull-up resistor pulls it high. A line is never actively driven high. This wiring allows multiple nodes to connect to the bus without short circuits from signal contention. High-speed systems (and some others) may use a current source instead of a resistor to pull-up only SCL or both SCL and SDA, to accommodate higher bus capacitance and enable faster rise times.


title: I²C

text: An important consequence of this is that multiple nodes may be driving the lines simultaneously. If "any" node is driving the line low, it will be low. Nodes that are trying to transmit a logical one (i.e. letting the line float high) can detect this and conclude that another node is active at the same time.


title: I²C

text: When used on SCL, this is called "clock stretching" and is a flow-control mechanism for targets. When used on SDA, this is called arbitration and ensures that there is only one transmitter at a time.


title: I²C

text: When idle, both lines are high. To start a transaction, SDA is pulled low while SCL remains high. It is illegal to transmit a stop marker by releasing SDA to float high again (although such a "void message" is usually harmless), so the next step is to pull SCL low.


title: I²C

text: Except for the start and stop signals, the SDA line only changes while the clock is low; transmitting a data bit consists of pulsing the clock line high while holding the data line steady at the desired level.


title: I²C

text: While SCL is low, the transmitter (initially the controller) sets SDA to the desired value and (after a small delay to let the value propagate) lets SCL float high. The controller then waits for SCL to actually go high; this will be delayed by the finite rise time of the SCL signal (the RC time constant of the pull-up resistor and the parasitic capacitance of the bus) and may be additionally delayed by a target's clock stretching.


title: I²C

text: Once SCL is high, the controller waits a minimum time (4 μs for standard-speed IC) to ensure that the receiver has seen the bit, then pulls it low again. This completes transmission of one bit.


title: I²C

text: After every 8 data bits in one direction, an "acknowledge" bit is transmitted in the other direction. The transmitter and receiver switch roles for one bit, and the original receiver transmits a single "0" bit (ACK) back. If the transmitter sees a "1" bit (NACK) instead, it learns that:


title: I²C

text: Only the SDA line changes direction during acknowledge bits; the SCL is always controlled by the controller.


title: I²C

text: One of the more significant features of the IC protocol is clock stretching. An addressed target device may hold the clock line (SCL) low after receiving (or sending) a byte, indicating that it is not yet ready to process more data. The controller that is communicating with the target may not finish the transmission of the current bit, but must wait until the clock line actually goes high. If the target is clock-stretching, the clock line will still be low (because the connections are open-drain). The same is true if a second, slower, controller tries to drive the clock at the same time. (If there is more than one controller, all but one of them will normally lose arbitration.)


title: I²C

text: The controller must wait until it observes the clock line going high, and an additional minimal time (4 μs for standard 100 kbit/s IC) before pulling the clock low again.


title: I²C

text: Although the controller may also hold the SCL line low for as long as it desires (this is not allowed since Rev. 6 of the protocol – subsection 3.1.1), the term "clock stretching" is normally used only when targets do it. Although in theory any clock pulse may be stretched, generally it is the intervals before or after the acknowledgment bit which are used. For example, if the target is a microcontroller, its IC interface could stretch the clock after each byte, until the software decides whether to send a positive acknowledgment or a NACK.


title: I²C

text: Clock stretching is the only time in IC where the target drives SCL. Many targets do not need to clock stretch and thus treat SCL as strictly an input with no circuitry to drive it. Some controllers, such as those found inside custom ASICs may not support clock stretching; often these devices will be labeled as a "two-wire interface" and not IC.


title: I²C

text: To ensure a minimal bus throughput, SMBus places limits on how far clocks may be stretched. Hosts and targets adhering to those limits cannot block access to the bus for more than a short time, which is not a guarantee made by pure IC systems.


title: I²C

text: Every controller monitors the bus for start and stop bits and does not start a message while another controller is keeping the bus busy. However, two controllers may start transmission at about the same time; in this case, arbitration occurs. Target transmit mode can also be arbitrated, when a controller addresses multiple targets, but this is less common. In contrast to protocols (such as Ethernet) that use random back-off delays before issuing a retry, IC has a deterministic arbitration policy. Each transmitter checks the level of the data line (SDA) and compares it with the levels it expects; if they do not match, that transmitter has lost arbitration and drops out of this protocol interaction.


title: I²C

text: If one transmitter sets SDA to 1 (not driving a signal) and a second transmitter sets it to 0 (pull to ground), the result is that the line is low. The first transmitter then observes that the level of the line is different from that expected and concludes that another node is transmitting. The first node to notice such a difference is the one that loses arbitration: it stops driving SDA. If it is a controller, it also stops driving SCL and waits for a STOP; then it may try to reissue its entire message. In the meantime, the other node has not noticed any difference between the expected and actual levels on SDA and therefore continues transmission. It can do so without problems because so far the signal has been exactly as it expected; no other transmitter has disturbed its message.


title: I²C

text: If the two controllers are sending a message to two different targets, the one sending the lower target address always "wins" arbitration in the address stage. Since the two controllers may send messages to the same target address, and addresses sometimes refer to multiple targets, arbitration must sometimes continue into the data stages.


title: I²C

text: Arbitration occurs very rarely, but is necessary for proper multi-controller support. As with clock stretching, not all devices support arbitration. Those that do, generally label themselves as supporting "multi-controller" communication.


title: I²C

text: One case which must be handled carefully in multi-controller IC implementations is that of the controllers talking to each other. One controller may lose arbitration to an incoming message, and must change its role from controller to target in time to acknowledge its own address.


title: I²C

text: In the extremely rare case that two controllers simultaneously send identical messages, both will regard the communication as successful, but the target will only see one message. For this reason, when a target can be accessed by multiple controllers, every command recognized by the target either must be idempotent or must be guaranteed never to be issued by two controllers at the same time. (For example, a command which is issued by only one controller need not be idempotent, nor is it necessary for a specific command to be idempotent when some mutual exclusion mechanism ensures that only one controller can be caused to issue that command at any given time.)


title: I²C

text: While IC only arbitrates between controllers, SMBus uses arbitration in three additional contexts, where multiple targets respond to the controller, and one gets its message through.


title: I²C

text: PMBus version 1.3 extends the SMBus alert response protocol in its "zone read" protocol. Targets may be grouped into "zones", and all targets in a zone may be addressed to respond, with their responses masked (omitting unwanted information), inverted (so wanted information is sent as 0 bits, which win arbitration), or reordered (so the most significant information is sent first). Arbitration ensures that the highest priority response is the one first returned to the controller.


title: I²C

text: There are several possible operating modes for IC communication. All are compatible in that the 100 kbit/s "standard mode" may always be used, but combining devices of different capabilities on the same bus can cause issues, as follows:


title: I²C

text: In all modes, the clock frequency is controlled by the controller(s), and a longer-than-normal bus may be operated at a slower-than-nominal speed by underclocking.


title: I²C

text: IC is popular for interfacing peripheral circuits to prototyping systems, such as the Arduino and Raspberry Pi. IC does not employ a standardized connector, however, board designers have created various wiring schemes for IC interconnections. To minimize the possible damage due to plugging 0.1-inch headers in backwards, some developers have suggested using alternating signal and power connections of the following wiring schemes: (GND, SCL, VCC, SDA) or (VCC, SDA, GND, SCL).


title: I²C

text: The vast majority of applications use IC in the way it was originally designed—peripheral ICs directly wired to a processor on the same printed circuit board, and therefore over relatively short distances of less than , without a connector. However using a differential driver, an alternate version of IC can communicate up to 20 meters (possibly over 100 meters) over CAT5 or other cable.


title: I²C

text: the 10-pin iPack connector carries IC; the 6P6C Lego Mindstorms NXT connector carries IC; a few people use the 8P8C connectors and CAT5 cable normally used for Ethernet physical layer to instead carry differential-encoded IC signals or boosted single-ended IC signals; and every HDMI and most DVI and VGA connectors carry DDC2 data over IC.


title: I²C

text: When there are many IC devices in a system, there can be a need to include bus buffers or multiplexers to split large bus segments into smaller ones. This can be necessary to keep the capacitance of a bus segment below the allowable value or to allow multiple devices with the same address to be separated by a multiplexer. Many types of multiplexers and buffers exist and all must take into account the fact that IC lines are specified to be bidirectional. Multiplexers can be implemented with analog switches, which can tie one segment to another. Analog switches maintain the bidirectional nature of the lines but do not isolate the capacitance of one segment from another or provide buffering capability.


title: I²C

text: Buffers can be used to isolate capacitance on one segment from another and/or allow IC to be sent over longer cables or traces. Buffers for bi-directional lines such as IC must use one of several schemes for preventing latch-up. IC is open-drain, so buffers must drive a low on one side when they see a low on the other. One method for preventing latch-up is for a buffer to have carefully selected input and output levels such that the output level of its driver is higher than its input threshold, preventing it from triggering itself. For example, a buffer may have an input threshold of 0.4 V for detecting a low, but an output low level of 0.5 V. This method requires that all other devices on the bus have thresholds which are compatible and often means that multiple buffers implementing this scheme cannot be put in series with one another.


title: I²C

text: Alternatively, other types of buffers exist that implement current amplifiers or keep track of the state (i.e. which side drove the bus low) to prevent latch-up. The state method typically means that an unintended pulse is created during a hand-off when one side is driving the bus low, then the other drives it low, then the first side releases (this is common during an IC acknowledgement).


title: I²C

text: When having a single controller, it is possible to have multiple IC buses share the same SCL line. The packets on each bus are either sent one after the other or at the same time. This is possible, because the communication on each bus can be subdivided in alternating short periods with high SCL followed by short periods with low SCL. And the clock can be stretched, if one bus needs more time in one state.


title: I²C

text: Advantages are using targets devices with the same address at the same time and saving connections or a faster throughput by using several data lines at the same time.


title: I²C

text: SMBus reserves some additional addresses. In particular, codice_1 is reserved for the SMBus host, which may be used by controller-capable devices, codice_2 is the "SMBus alert response address" which is polled by the host after an out-of-band interrupt, and codice_3 is the default address which is initially used by devices capable of dynamic address assignment.


title: I²C

text: Although MSB 1111 is reserved for Device ID and 10-bit target (slave) addressing, it is also used by VESA DDC display dependent devices such as pointing devices.


title: I²C

text: An IC "transaction" consists of one or more "messages". Each message begins with a start symbol, and the transaction ends with a stop symbol. Start symbols after the first, which begin a message but not a transaction, are referred to as "repeated start" symbols.


title: I²C

text: Each message is a read or a write. A transaction consisting of a single message is called either a read or a write transaction. A transaction consisting of multiple messages is called a combined transaction. The most common form of the latter is a write message providing intra-device address information, followed by a read message.


title: I²C

text: Many IC devices do not distinguish between a combined transaction and the same messages sent as separate transactions, but not all. The device ID protocol requires a single transaction; targets are forbidden from responding if they observe a stop symbol. Configuration, calibration or self-test modes which cause the target to respond unusually are also often automatically terminated at the end of a transaction.


title: I²C

text: In order to avoid false marker detection, there is a minimum delay between the SCL falling edge and changing SDA, and between changing SDA and the SCL rising edge. Note that an IC message containing data bits (including acknowledges) contains clock pulses.


title: I²C

text: IC lends itself to a "bus driver" software design. Software for attached devices is written to call a "bus driver" that handles the actual low-level IC hardware. This permits the driver code for attached devices to port easily to other hardware, including a bit-banging design.


title: I²C

text: Below is an example of bit-banging the IC protocol as an IC controller (master). The example is written in pseudo C. It illustrates all of the IC features described before (clock stretching, arbitration, start/stop bit, ack/nack).


title: I²C

text: When developing or troubleshooting systems using IC, visibility at the level of hardware signals can be important.


title: I²C

text: There are a number of IC host adapter hardware solutions for making a IC controller or target connection to host computers, running Linux, Mac or Windows. Most options are USB-to-IC adapters. Not all of them require proprietary drivers or APIs.


title: I²C

text: IC protocol analyzers are tools that sample an IC bus and decode the electrical signals to provide a higher-level view of the data being transmitted on the bus.


title: I²C

text: When developing and/or troubleshooting the IC bus, examination of hardware signals can be very important. Logic analyzers are tools that collect, analyze, decode, and store signals, so people can view the high-speed waveforms at their leisure. Logic analyzers display time stamps of each signal level change, which can help find protocol problems. Most logic analyzers have the capability to decode bus signals into high-level protocol data and show ASCII data.


title: I²C

text: On low-power systems, the pull-up resistors can use more power than the entire rest of the design combined. On these, the resistors are often powered by a switchable voltage source, such as a DIO from a microcontroller. The pull-ups also limit the speed of the bus and have a small additional cost. Therefore, some designers are turning to other serial buses, e.g. I3C or SPI, that do not need pull-ups.


title: I²C

text: The assignment of target addresses is a weakness of IC. Seven bits is too few to prevent address collisions between the many thousands of available devices. What alleviates the issue of address collisions between different vendors and also allows to connect to several identical devices is that manufacturers dedicate pins that can be used to set the target address to one of a few address options per device. Two or three pins is typical, and with many devices, there are three or more wiring options per address pin.


title: I²C

text: 10-bit IC addresses are not yet widely used, and many host operating systems do not support them. Neither is the complex SMBus "ARP" scheme for dynamically assigning addresses (other than for PCI cards with SMBus presence, for which it is required).


title: I²C

text: Automatic bus configuration is a related issue. A given address may be used by a number of different protocol-incompatible devices in various systems, and hardly any device types can be detected at runtime. For example, codice_6 may be used by a 24LC02 or 24C32 EEPROM, with incompatible addressing; or by a PCF8563 RTC, which cannot reliably be distinguished from either (without changing device state, which might not be allowed). The only reliable configuration mechanisms available to hosts involve out-of-band mechanisms such as tables provided by system firmware, which list the available devices. Again, this issue can partially be addressed by ARP in SMBus systems, especially when vendor and product identifiers are used; but that has not really caught on. The Rev. 3 version of the IC specification adds a device ID mechanism.


title: I²C

text: IC supports a limited range of speeds. Hosts supporting the multi-megabit speeds are rare. Support for the Fm+ 1 Mbit/s speed is more widespread, since its electronics are simple variants of what is used at lower speeds. Many devices do not support the 400 kbit/s speed (in part because SMBus does not yet support it). IC nodes implemented in software (instead of dedicated hardware) may not even support the 100 kbit/s speed; so the whole range defined in the specification is rarely usable. All devices must at least partially support the highest speed used or they may spuriously detect their device address.


title: I²C

text: Devices are allowed to stretch clock cycles to suit their particular needs, which can starve bandwidth needed by faster devices and increase latencies when talking to other device addresses. Bus capacitance also places a limit on the transfer speed, especially when current sources are not used to decrease signal rise times.


title: I²C

text: Because IC is a shared bus, there is the potential for any device to have a fault and hang the entire bus. For example, if any device holds the SDA or SCL line low, it prevents the controller from sending START or STOP commands to reset the bus. Thus it is common for designs to include a reset signal that provides an external method of resetting the bus devices. However many devices do not have a dedicated reset pin, forcing the designer to put in circuitry to allow devices to be power-cycled if they need to be reset.