title: Mount Katahdin

text: The mountain massif itself consists of multiple peaks. Baxter Peak is the tallest, and is the official northern terminus of the Appalachian Trail. South Peak and Pamola Peak are southeast and east of Baxter Peak, respectively, along the Knife Edge ridgeline, while Hamlin Peak lies to the north.


title: Mount Katahdin

text: There is low lake country to the south and west of Katahdin, and lowlands extending east to the Atlantic and north to the Saint Lawrence River in Canada.


title: Mount Katahdin

text: It is commonly thought that Katahdin is the first place in the United States mainland to receive sunlight in the morning, but this is incorrect. Other mountains lower in elevation but farther to the east or southeast see the first sunrise of the day, depending on the season.


title: Mount Katahdin

text: Katahdin is part of a laccolith that formed in the Acadian orogeny when an island arc collided with eastern North America approximately 400 million years ago. On the sides of Katahdin are four glacial cirques carved into the granite by alpine glaciers and in these cirques behind moraines and eskers are several ponds.


title: Mount Katahdin

text: In Baxter State Park, many outcrops of sedimentary rocks have striations, whereas Katahdin Granite and Traveler Rhyolite lava have weathered surfaces on which striations are commonly not preserved. Bedrock surfaces of igneous rocks which were buried by glacial sediments and only recently exposed have well preserved striations, as in the vicinity of Ripogenus Dam. Several outcrops of sedimentary rocks along the Patten Road show striations, especially on the north side of the road at Hurricane Deck. A few outcrops near the Pattern Road just north of Horse Mountain are striated, as are several outcrops of sedimentary rocks along the road from Trout Brook Farm northward to Second Lake Matagamon.


title: Mount Katahdin

text: Fauna include black bear, deer, and moose as well as black flies and mosquitos in the spring. A subspecies of Arctic butterfly, known as the Katahdin Arctic ("Oeneis polixenes katahdin") is specific to the area, and is currently listed as endangered.


title: Mount Katahdin

text: Among the birds are Bicknell's thrush and various songbirds and raptors. A study of the animal communities was published by Irving H. Blake in 1926. The flora includes pine, spruce, fir, hemlock, beech, maple, birch, aspen, and pincushion plant ("Diapensia lapponica").


title: Mount Katahdin

text: Katahdin is referred to 60 years after Field's climb of Agiokochuk (Mount Washington) in the writings of John Gyles, a teenage colonist who was captured near Portland, Maine, in 1689 by the Abenaki. While in the company of Abenaki hunting parties, he traveled up and down several Maine rivers including both branches of the Penobscot, passing close to "Teddon". He remarked that it was higher than the White Hills above the Saco River.


title: Mount Katahdin

text: Among some Native Americans, Katahdin was believed to be the home of the storm god Pamola, and thus an area to be avoided.


title: Mount Katahdin

text: The first recorded climb of "Catahrdin" was by Massachusetts surveyors Zackery Adley and Charles Turner, Jr. in August 1804. In the 1840s Henry David Thoreau climbed Katahdin, which he spelled "Ktaadn"; his ascent is recorded in a well-known chapter of "The Maine Woods". A few years later Theodore Winthrop wrote about his visit in "Life in the Open Air". Painters Frederic Edwin Church and Marsden Hartley are well-known artists who created landscapes of Katahdin. On 30 November 2011, Christie's auctioned Church's 1860 painting "Twilight (Katahdin)" for $3.1 million. The letter describing the ascent of Charles Turner Jr. states that they began at the (West Branch Penobscot) at 8:00 a.m. and arrived on the summit at 5:00 p.m. guided by two Native Americans who were initially cautious but when the "cold part of the mountain" was reached and sensing the determination of the others became ambitious to reach the top first. Turner lists his party as: William Howe, Amos Patten, Joseph Treat, Samuel Call, William Rice, Richard Winslow, Charles Turner, Jr. In the 1930s Governor Percival Baxter began to acquire land and finally deeded more than 200,000 acres (809 km) to the State of Maine for a park, named Baxter State Park after him. The summit was officially recognized by the US Board on Geographic Names as "Baxter Peak" in 1931.


title: Mount Katahdin

text: As the northern terminus of the Appalachian Trail and southern terminus of the International Appalachian Trail, Katahdin is a popular hiking and backpacking destination and the centerpiece of Baxter State Park. Baxter State Park is open year-round, though strictly regulated in winter. The overnight camping season is, weather permitting, from May 15 to October 15 each year, with some campgrounds staying open until October 22. Capacity limits have been placed on day use parking at the trailheads to minimize the overuse of trails.


title: Mount Katahdin

text: Mt. Katahdin has several trails leading up to Baxter, Pamola, or Hamlin Peaks These trails start right up the mountain, but each trail on the mountain ends up taking eight to ten hours round-trip depending on ability. The rest of the trails go up the north side or west side of the mountain. These are accessed from the Chimney Pond Trail. For these trails, hikers must park at the Roaring Brook Campground and hike in. All trails are maintained by the Baxter State Park Authority, which runs the State Park. All of the trails on the mountain are classified as very strenuous, the highest classification the Park Authority gives, except for Saddle (strenuous), Hamlin Ridge trail (moderate), and Chimney Pond (moderate).


title: Mount Katahdin

text: The most famous hike to the summit goes along Knife Edge, a glacial Arête which traverses the ridge between Pamola Peak and Baxter Peak. The mountain has claimed 23 lives between 1963 and 2012, mostly from exposure in bad weather and falls from the Knife Edge. There have been more than 60 deaths on Katahdin since 1933 including October 8 and 9, 2020. For about 3/10 of a mile the trail is 3 feet wide, with a drop off on either side. The Knife Edge is closed during periods of high wind.


title: Mason jar

text: A Mason jar, also known as a canning jar or fruit jar, is a glass jar used in home canning to preserve food. It was named after American tinsmith John Landis Mason, who patented it in 1858. The jar's mouth has a screw thread on its outer perimeter to accept a metal ring or "band". The band, when screwed down, presses a separate stamped steel disc-shaped lid against the jar's rim.


title: Mason jar

text: Mason lost his patent for the jars and numerous other companies started manufacturing similar jars. Over the years, the brand name "Mason" became the genericized trademark for that style of glass home canning jar, and the word "Mason" can be seen on many Ball and Kerr brand jars. The style of jar is occasionally referred to by common brand names such as Ball jar (in the eastern US) or Kerr jar (in the western US) even if the individual jar isn't that brand.


title: Mason jar

text: In early 20th century America, Mason jars became useful to those who lived in areas with short growing seasons. The jars became an essential part of farming culture, while being used at fairs to display jams and pickles for judging and awards. This was a reflection of the labour that went into making the jams. The jams, pickles, and sauces would be given and exchanged as gifts during the holidays as a canned preserved good was of much value. The peak use of Mason jars came during World War II, when the U.S. government rationed food encouraging the public to grow their own. As migration to cities occurred, along with rise of the refrigerators, more efficient transport of goods made fruit and vegetables available year round emphasizing less need for food preservation. Contemporary industrial preservation transitioned to the use of plastics like bakelite and nylon and billions of containers were produced instead.


title: Mason jar

text: In the early to mid 2010s a revival of the Mason Jar occurred from a mix of the rise of thrifting and adoption by hipsters. Used as a novelty by major corporations like 7-Eleven to advertise new drinks, for greenwashing being branded as zero waste consumer lifestyle, or as a trendy presentation for dessert. In a search for authenticity, commodification of Mason jars occurred leading to irony. As drinking out of canning gear highlighted overconsumption and lack of scarcity, the opposite of the designed intention of the jars. Its utility has been praised for use as a variety of household functional and decorative purposes; such as an oil lantern, soap dispenser, speaker or vase.


title: Mason jar

text: On August 15, 2017, the Registrar at National Day Calendar proclaimed National Mason Jar Day to be observed annually as a National Holiday on November 30th, beginning in 2017.


title: Mason jar

text: French chef Nicolas Appert invented the method of preserving food by enclosing it in sealed containers. Among the earliest glass jars used for home canning were wax sealers, named in reference to the sealing wax that was poured into a channel around the lip to secure a tin lid. This process, though complicated and error-prone, became popular in the late 1830s or early 1840s and was still used to seal fruit jars until about 1890. The wax sealing process was largely the only one available until other sealing methods were developed.


title: Mason jar

text: In 1858, a Vineland, New Jersey tinsmith named John Landis Mason (1832–1902) invented and patented a screw threaded glass jar or bottle that became known as the Mason jar (U.S. Patent No. 22,186.) From 1857, when it was first patented, to the present, Mason jars have had hundreds of variations in shape and cap design. After Mason's patent expired, many other manufacturers produced glass jars for home canning using the Mason-style jar.


title: Mason jar

text: The initial form of closure for the glass canning jar was a zinc screw-on cap, the precursor to today's screw-on lids. It usually had a milk-glass liner, but some of the earliest lids may have had transparent glass liners. The cap screwed down onto a rubber ring on the shoulder of the jar, not the lip. Between 1860 and 1900, many other patents were issued for Mason jar improvements and closures. In 1903 Alexander Kerr introduced lids with a permanent rubber seal. His improved design in 1915 used the modern design. Jars are closed with two-piece metal lids that seal on the rim. The jar lid has a rubber or rubber-like sealing surface and is held in place by a separate metal band.


title: Mason jar

text: Mason sold the patents for the Mason jar, to the Sheet Metal Screw Company of Lewis R. Boyd in 1859. Boyd had patented a white "milk-glass" insert for the zinc screw lids to theoretically lessen the chances that food would be tainted by contact with the metal lid. In 1871, Mason partnered with Boyd in the Consolidated Fruit Jar Company which licensed Mason jar patents to numerous glass makers. Letters of patent issued to Mason on May 10, 1870, for improvements to his fruit-canning jar was determined to be invalid as a result of a patent infringement case brought before the Southern District of New York on June 11, 1874. The court acknowledged that Mason had invented the jar in 1859, but he did not apply for a patent for an improved version of the fruit jar until 1868. In the meantime, several others had patented designs and Mason had known these jars were being produced and sold. The court ruled that Mason's delay in protecting his patent indicated he had abandoned his invention in the intervening years between 1859 and 1868 and had forfeited his patent. The court's decision allowed other manufacturers to patent, produce, and sell glass jars for canning.


title: Mason jar

text: Variations of the Mason jar include the "Improved Mason" which sealed on a shoulder above the thread instead of below and the Atlas Strong Shoulder which had a reinforced shoulder area as the original design was subject to cracks from the stress at the sealing point. A new type of Mason jar known as a "bead" jar was introduced circa 1910 - 1915. These continuous screw-thread jars were designed with a bead between the screw threads and the shoulder as a sealing surface. The Ball Corporation's "Perfect Mason" jar, one of the most common jars of this style, was introduced circa 1913 and produced until the mid-20th century. It had several variations, including a square-shaped jar.


title: Mason jar

text: The Ball Corporation, which once dominated the market as the largest domestic manufacturer of home-canning jars, spun off its home-canning business in 1993. In 1939 the company manufactured 54% of all the canning jars made in the US. Ball ceased production of canning jars when its subsidiary, Alltrista, became a separate company in 1993. Ball Corp. acquired certain Kerr assets, including factories, in 1992 and the Kerr brand of glass home canning jars was absorbed into Alltrista in 1996. Alltrista was renamed Jarden Corporation in 2002. Newell Brands acquired Jarden Corporation in 2016. As of 2022, Newell manufactures canning jars under the brand names Ball, Bernardin, Golden Harvest, and Kerr.


title: Mason jar

text: The jars are made with either a wide mouth (3 inches) or regular mouth (2⅜ inches) opening. They come in a variety of sizes, from 4 ounces to a gallon. The half-gallon size and larger are not recommended for canning purposes. The most typical sizes used in canning are quart, pint, and half-pint. The jars typically have their brand name embossed on the side, though jars may also have a decorative design such as a quilting pattern or may be completely blank and smooth. Jars may be washed and reused so long as they have no chips or cracks.


title: Mason jar

text: In the illustration, the left half are wide mouth and the right half are regular mouth. From left to right: wide mouth half-pint, pint, 1½ pint, quart, then regular mouth quart, pint, half-pint, quarter-pint. The lids and bands are also shown. The two rightmost jars are quilted.


title: Mason jar

text: The lids are made of metal with a ring of sealing compound which acts as a gasket against the jar's rim. New sealing compound is only good for about five years from date of manufacture, so older unused lids should be discarded. Lids may not be used more than once. New lids are slightly domed (convex). During processing, air is vented from the jar and the food shrinks. While cooling, a vacuum is created inside the jar, sucking the dome downward (concave) — an indication that a seal is good. Processed jars should be stored in a manner where the lids are not disturbed and the seals remain intact.


title: Mason jar

text: The metal screw bands are used to properly align the lids onto the jar, and to hold the lid in place during processing. They should be removed after processing and may be reused many times as long as they are kept rust-free and undented.


title: Mason jar

text: The value of a jar is related to its age, rarity, color, and condition. A jar's age and rarity can be determined by the color, shape, mold and production marks of the glass, and the jar's closure. Mason jars usually have a proprietary brand embossed on the jar. Early jars embossed with "Mason's Patent November 28th 1858" that date from the late 1850s to early 1860s closely match the illustrations of Mason's 1858 patents. Mouth-blown (or hand-blown) jars embossed with a version of "Mason's Patent November 28th 1858" were made about 1857 to 1908 and often had a ground lip as well. By 1908 semi-automatic machines manufactured the majority of these jars. Machine-made Mason jars that originated around 1909 have a sealing surface on a bead ledge below the threads. This type of jar dominated the market by the mid to late 1910s. Manufacturers continued to make jars with the beaded seal after the mid-twentieth century. Ball's "Ideal" canning jar, which first appeared around 1915 and was discontinued in 1962, is one of the company's best-known jars and is popular among collectors.


title: Mason jar

text: Most antique jars that are not colorless are aqua or "Ball blue," a blue-green shade that was named for the Ball Corporation, a prevalent jar manufacturer. Most mouth-blown Mason jars embossed with some type of 1858 patent date were produced in aqua glass. The Ball brand of Mason jars were manufactured in several colors, but the most common color was the distinctive "Ball blue," which the Ball Corporation used in its jars from about 1910 to 1930. Mason jars with this particular color of glass may be attributed to Ball, since "virtually no other bottle or jar was made in that color."


title: Mason jar

text: Older styles of home canning jars are "Not Recommended" by the U.S.-based National Center for Home Food Preservation, the United States Department of Agriculture, and University Extension Services. These include: those using a zinc cap and a rubber jar ring, and those using a glass lid, wire bail, and rubber sealing ring. These provide "no definitive way to determine if a vacuum seal is formed".


title: Genocide of Yazidis by the Islamic State

text: A genocide of Yazidis by the Islamic State was carried out in the Sinjar area of northern Iraq in the mid-2010s. The genocide led to the expulsion, flight and effective exile of the Yazidis. Thousands of Yazidi women and girls were forced into sexual slavery by ISIL, and thousands of Yazidi men were killed. About 5,000 thousand Yazidi civilians were killed during what has been called a "forced conversion campaign" carried out by ISIL in Northern Iraq. The genocide began after the withdrawal of Iraqi forces and Peshmerga, which left the Yazidis defenseless.


text: ISIL's persecution of the Yazidis gained international attention and led to the American-led intervention in Iraq, which started with United States airstrikes against ISIL. Additionally, the US, UK, and Australia made emergency airdrops to Yazidis who had fled to a mountain range. YPG and PKK fighters opened a humanitarian corridor to the Sinjar Mountains and helped the Yazidis. By 2015, ISIL's actions against the Yazidi population had resulted in approximately 500,000 refugees.


text: The genocide has been recognized by several bodies of the United Nations and national and multi-national organizations.


text: The Yazidis are monotheists who believe in Melek Taus, a benevolent angel who appears as a peacock. The self-proclaimed Islamic State of Iraq and the Levant and other Muslims in the region tend to view the peacock angel as the malevolent creature Lucifer or Shaitan and they consider the Yazidis 'devil worshippers'. Unlike for Judaism and Christianity, ISIL does not consider Yazidis as People of the book or eligible for Dhimmi and related protections.


text: In August 2014, more than 300 Yazidi families were threatened and forced to choose between conversion to Sunni Islam or death.


text: On 3 August 2014, ISIL militants attacked and took over Sinjar in northern Iraq, a Kurdish-controlled town that was predominantly inhabited by Yazidis, and the surrounding area.


text: Yazidis, and internet postings of ISIL, have reported summary executions that day by ISIL militants, leading to 200,000 civilians fleeing Sinjar, of whom around 50,000 Yazidis were reportedly escaping to the nearby Sinjar Mountains. They were trapped on Mount Sinjar, surrounded by ISIL militants and facing starvation and dehydration.


text: On 4 August 2014, Prince Tahseen Said, Emir of the Yazidi, issued a plea to world leaders calling for assistance on behalf of the Yazidi facing attack from ISIL.


text: On 3 August 2014, ISIL killed the men from the al-Qahtaniya area, ten Yazidi families fleeing were attacked by ISIL; and ISIL shot 70 to 90 Yazidi men in Qiniyeh village.


text: On 4 August, ISIL fighters attacked Jabal Sinjar, killed 30 Yazidi men; 60 more Yazidi men were killed in the village of Hardan. On the same day, Yazidi community leaders stated that at least 200 Yazidis had been killed in Sinjar (see Sinjar massacre), and 60–70 near Ramadi Jabal.


text: According to reports from surviving Yazidi, between 3 and 6 August, more than 50 Yazidi were killed near Dhola village, 100 in Khana Sor village, 250–300 in Hardan area, more than 200 on the road between Adnaniya and Jazeera, dozens near al-Shimal village, and on the road from Matu village to Jabal Sinjar.


text: On 10 August, according to statements by the Iraqi government, ISIL militants buried alive an undefined number of Yazidi women and children in northern Iraq in an attack that killed 500 people.


text: Those who escaped across the Tigris River into Kurdish-controlled areas of Syria on 10 August gave accounts of how they had seen individuals also attempting to flee who later died.


text: On 15 August, in the Yazidi village of Kojo, south of Sinjar, after the whole population had received the jihadist ultimatum to convert or be killed, over 80 men were killed.


text: A witness recounted that the villagers were first converted under duress, but when the village elder refused to convert, all of the men were taken in trucks under the pretext of being led to Sinjar, and gunned down along the way.


text: According to reports from survivors interviewed by OHCHR, on 15 August, the entire male population of the Yazidi village of Khocho, up to 400 men, were rounded up and shot by ISIL, and up to 1,000 women and children were abducted; on the same day, up to 200 Yazidi men were reportedly executed for refusing conversion in a Tal Afar prison.


text: Between 24 and 25 August 14 elderly Yazidi men were executed by ISIL in the Sheikh Mand Shrine, and the Jidala village Yazidi shrine was blown up. On 1 September, the Yazidi villages of Kotan, Hareko and Kharag Shafrsky were set afire by ISIL, and on 9 September, Peshmerga fighters discovered a mass grave containing the bodies of 14 executed civilians, presumably Yazidis.


text: According to an OHRCR/UNAMI report on 26 September, by the end of August, 1,600–1,800 or more Yazidis who had been murdered, executed, or died from starvation.


text: In early October, Matthew Barber, a scholar of Yazidi history at the University of Chicago, estimated that 5,000 Yazidi men had been killed by ISIL.


text: According to the United Nations, ISIL had massacred 5,000 Yazidi men and kidnapped about 7000 Yazidi women and girls (who were forced into sex slavery) in northern Iraq in August 2014.


text: In May 2015, the Yazidi Progress Party released a statement in which they said that 300 Yazidi captives were killed on 1 May by ISIL in the Tal Afar, Iraq.


text: A 2017 survey by the "PLOS Medicine" journal significantly decreased the number of Yazidis killed however concurrently raised the number abducted with 2,100 to 4,400 deaths and 4,200 to 10,800 abductions.


text: In several villages, local Sunnis were reported to have sided with ISIL, betraying Yazidis for slaughter once ISIL arrived, and even possibly colluding in advance with ISIL to lie to Yazidis, to lure them into staying put until the terrorists invaded, although there was also one report of Sunnis helping Yazidis to escape.


text: The 2017 report of the United Nations Secretary-General on conflict-related sexual violence detailed the brutal attacks on Mosul, Sinjar, Tall’Afar, and the Ninewa plains in the north and subjection of civilians to sexual violence on a horrific scale primarily against women and girls from ethnic and religious minority groups. According to declarations, 971 Yazidi women and girls have been freed while 1,882 remained enslaved in Iraq and Syria. Forced transfer of Yazidis from Mosul to Raqqah (Syria), trafficking, the sale and trade of women and children, and the use of sexually enslaved women as human shields by ISIL during the Mosul operations were also reported.


text: On 3 August, ISIL abducted women and children from the al-Qahtaniya area, and 450–500 abducted Yazidi women and girls were taken to Tal Afar; hundreds more to Si Basha Khidri and then Ba'aj. When ISIL fighters attacked Jabal Sinjar on 4 August, they abducted a number of women in the Yazidi village of Hardan, wives and daughters were abducted; other Yazidi women were abducted in other villages in the area. On 6 August, ISIL kidnapped 400 Yazidi women in Sinjar to sell them as sex slaves. According to reports from surviving Yazidi, between 3 and 6 August 500 Yazidi women and children were abducted from Ba'aj and more than 200 from Tal Banat. According to a statement by the Iraqi government on 10 August 2014, hundreds of women were taken as slaves in northern Iraq. On 15 August, in the Yazidi village of Kojo, south of Sinjar, over 100 women were abducted, though according to some reports from survivors, up to 1,000 women and children of the Yazidi village of Khocho were abducted. According to an OHRCR/UNAMI report on 26 September, by the end of August up to 2,500 Yazidis, mostly women and children, had been abducted.


text: In early October, Matthew Barber, a scholar of Yazidi history at the University of Chicago, compiled a list of names of 4,800 Yazidi women and children who had been captured (estimating the total number of abducted people to be possibly up to 7,000).


text: The abducted Yazidi women were sold into slave markets with ISIL "using rape as a weapon of war" according to CNN, with the group having gynaecologists ready to examine the captives. Yazidi women were physically observed, including examinations to see if they were virgins or if they were pregnant. Women who were found to be pregnant were taken by the ISIL gynaecologists and forced abortions were performed on them.


text: Haleh Esfandiari from the Woodrow Wilson International Center for Scholars highlighted the abuse of local women by ISIL militants after they have captured an area. "They usually take the older women to a makeshift slave market and try to sell them. The younger girls ... are raped or married off to fighters", she said, adding, "It's based on temporary marriages, and once these fighters have had sex with these young girls, they just pass them on to other fighters."


text: Speaking of Yazidi women captured by ISIL, Nazand Begikhani said in October 2014, "These women have been treated like cattle ... They have been subjected to physical and sexual violence, including systematic rape and sex slavery. They've been exposed in markets in Mosul and in Raqqa, Syria, carrying price tags." Yazidi girls in Iraq allegedly raped by ISIL fighters have committed suicide by jumping to their death from Mount Sinjar, as described in a witness statement.


text: A United Nations report issued on 2 October 2014, based on 500 interviews with witnesses, said that ISIL took 450–500 women and girls to Iraq's Nineveh region in August where "150 unmarried girls and women, predominantly from the Yazidi and Christian communities, were reportedly transported to Syria, either to be enslaved to ISIL fighters as a 'reward' or to be sold as sex slaves".


text: Also in October 2014, a UN report revealed that ISIL had detained 5,000 to 7,000 Yazidi women as slaves or forced brides in northern Iraq in August 2014.


text: On 4 November 2014, Dr. Widad Akrawi of Defend International said that "the international community should define what's happening to the Yezidis as a crime against humanity, crime against cultural heritage of the region and ethnic cleansing", adding that Yazidi females are being "subjected to as systematic gender-based violence and the use of slavery and rape as a weapon of war."


text: A month earlier, President of Defend International dedicated her 2014 International Pfeffer Peace Award to the Yazidis, Christians and all residents of Kobane because, she said, facts on the ground demonstrate that these peaceful people are not safe in their enclaves, partly because of their ethnic origin and/or religion and they are therefore in urgent need for immediate attention from the global community. She asked the international community to make sure that the victims are not forgotten; they should be rescued, protected, fully assisted and compensated fairly.


text: In June 2017, reports from Vian Dakhil of the Iraqi parliament told of a captured sex slave being fed her own one-year-old child. The woman was starved for three days in a cellar and was finally given a meal by her captors. When finished, they said "We cooked your one-year-old son that we took from you, and this is what you just ate".


text: On 3 November 2014, the "price list" for Yazidi and Christian females issued by ISIL surfaced online, and Dr. Widad Akrawi and her team were the first to verify the authenticity of the document. On 4 November 2014, a translated version of the document was shared by Akrawi. On 4 August 2015, the same document was confirmed as genuine by a UN official.


text: Writing in mid 2016, Lori Hinnant, Maya Alleruzzo and Balint Szlanko of the Associated Press report that ISIL tightened "its grip on the estimated 3,000 women and girls held as sex slaves" even while it was losing territory to Iraqi forces. ISIL sells the women on encrypted smart phone apps, "primarily on Telegram and on Facebook" and to a lesser degree on WhatsApp. In advertisements for the girls seen by AP,


text: many of the women and girls are dressed in finery, some in heavy makeup. All look directly at the camera, standing in front of overstuffed chairs or brocade curtains in what resembles a shabby hotel ballroom. Some are barely out of elementary school. Not one looks older than 30.


text: Various forms of reproductive violence were enacted against the Yazidi women and children to prevent birth. Captured Yazidis were taken as slaves and forced to use contraceptive pills and injections, and those captured pregnant were victims of forced abortions. Reports covered that Yazidi women and girls were told that they had to abort their previous unborn children since ISIL fighters were interested only in making Muslim babies. Forced impregnation with the intent to prevent the birth of Yazidi babies is also another form of reproductive violence and a measure taken against the group. These destructive intents and acts are described as preventing future procreation and causing severe long-term physical, psychological, and socio-political effects.


text: Since 2014, efforts have been ongoing to rescue those enslaved by the Islamic State, including paying ransoms. Many were freed by the Syrian Democratic Forces as they took territory from the Islamic State in the Rojava-Islamist conflict. In November 2014 "The New York Times" reported on the accounts given by five who escaped the Islamic State of their captivity and abuse.


text: According to Mirza Dinnayi, founder of the German-Iraqi aid organization Luftbrücke Irak, ISIL registers "every slave, every person under their owner, and therefore if she escapes, every Daesh [ISIL] control or checkpoint, or security force - they know that this girl ... has escaped from this owner".


text: For over a year after the girls were first enslaved, "Arab and Kurdish smugglers managed to free an average of 134" slaves a month. But by May 2016, an ISIL "crackdown reduced those numbers to just 39 in the last six weeks, according to figures provided by the Kurdistan regional government". ISIL fighters targeted and killed "smugglers who rescue the captives". In 2016, funds provided by the Kurdistan Regional Government to buy the women out of slavery were cut off as a result of the collapse in the price of oil and disputes with Iraq's central government over revenues.


text: The freeing of Yazidi women continues, with some being found at the homes of Islamic State commanders in Ankara in July 2020. One seven-year old Yazidi girl was rescued from two ISIS commanders in Ankara by Turkish authorities in February 2021.


text: In its digital magazine "Dabiq", ISIL explicitly claimed religious justification for enslaving Yazidi women. ISIL's religious justifications were refuted by Islamic scholars.


text: According to "The Wall Street Journal", ISIL appeals to apocalyptic beliefs and claims "justification by a Hadith that they interpret as portraying the revival of slavery as a precursor to the end of the world". In late 2014, ISIL released a pamphlet on the treatment of female slaves. "The New York Times" said in August 2015 that "[t]he systematic rape of women and girls from the Yazidi religious minority has become deeply enmeshed in the organization and the radical theology of the Islamic State in the year since the group announced it was reviving slavery as an institution."


text: The ISIL offensive in the Sinjar area of northern Iraq, 3–4 August, caused 30,000–50,000 Yazidis to flee into the Sinjar Mountains (Jabal Sinjar) fearing they would be killed by ISIL. They had been threatened with death if they refused conversion to Islam. A UN representative said that "a humanitarian tragedy is unfolding in Sinjar".


text: On 3 and 4 August 14 or more, Yazidi children and some elderly or people with disabilities died of hunger, dehydration, and heat on Mount Sinjar. By 6 August, according to reports from survivors, 200 Yazidi children while fleeing to Mount Sinjar had died from thirst, starvation, heat and dehydration.


text: Fifty thousand Yazidis, besieged by ISIL on Mount Sinjar, were able to escape after Kurdish People's Protection Units and PKK broke ISIL siege on the mountains. The majority of them were rescued by Kurdish PKK and YPG fighters. Multinational rescue operation involved dropping of supplies on the mountains and evacuation of some refugees by helicopters. During the rescue operation, on 12 August, an overloaded Iraqi Air Force helicopter crashed on Mount Sinjar, killing Iraqi Air Force Major General Majid Ahmed Saadi (the pilot) and injuring 20 people.


text: By 20 October, 2,000 Yazidis, mainly volunteer fighters, who had remained behind to protect the villages, but also civilians (700 families who had not yet escaped), were reported as still in the Sinjar area, and were forced by ISIL to abandon the last villages in their control, Dhoula and Bork, and retreat to the Sinjar Mountains.


text: In an article by "The Washington Post", it was stated that an estimated 7,000 Yazidis had been forced to convert to "the Islamic State group's harsh interpretation of Islam". Yazidi boys were taken to Raqqa, Syria to be trained to fight for ISIL, with some being forced to fight as U.S.-led forces closed in on the group.


text: Following ISIL's retreat from Iraqi and Kurdish forces in the region during late 2017 campaigns, both governments laid claim to the area. The Yazidi population, with only about 15% returning to Sinjar during the period, was caught in the political crossfire. Yazidis returned to an abandoned town of crumbling buildings, leftover IEDs and the remains of those killed during the massacre.


text: In November 2017, a mass grave of about 70 people was uncovered and a month later in December, another mass grave was discovered holding about 90 victims.


text: Thousands are still missing. To aid in the search, local business owners use their network of contacts to locate people. Former captives use their contacts to buy back Yazidi women sold into sex slavery and return them to their family. This additionally prevents their organs from being sold on the black market, each of which, according to an Islamic State informant, can be sold for $60,000 - $70,000.


text: In January 2015, about 200 Yazidis were released by ISIL. Kurdish military officials believed they were released because they were a burden. On 8 April 2015, 216 Yazidis, with the majority being children and elderly, were released by ISIL after being held captive for about eight months. Their release occurred following an offensive by U.S.-led air assaults and pressure from Iraqi ground forces who were pushing northward and in the process of retaking Tikrit. According to General Hiwa Abdullah, a peshmerga commander in Kirkuk, those released were in poor health with signs of abuse and neglect visible.


text: In March 2016, Iraqi security forces managed to free a group of Yazidi women held hostage by ISIL in a special operation behind ISILs lines in Mosul.


text: In March 2016, the militant group Kurdistan Workers' Party managed to free 51 Yazidis held hostages by ISIL in an operation called 'Operation Vengeance for Martyrs of Shilo' Three Kurdistan Workers' Party guerrillas died during the operation.


text: In April 2016, the Kurdistan Workers' Party with the Sinjar Resistance Units managed to free another 53 Yazidis held hostages by ISIL.


text: Many international organisations, governments and parliaments, as well as groups have classified ISIL's treatment of the Yazidis as genocide, and condemned it as such. The Genocide of Yazidis has been officially recognized by several bodies of the United Nations and the European Parliament. Many states have recognized it as well, for example the National Assembly of Armenia, the Australian parliament, the British Parliament, the Canadian parliament, and the United States House of Representatives. Multiple individual human rights activists such as Nazand Begikhani and Dr. Widad Akrawi have also advocated for this view.


text: In 2017, CNN journalists Jomana Karadsheh and Chris Jackson interviewed former Yazidi captives and exclusively filmed the Daesh Criminal Investigations Unit (DCIU), a team of Iraqi Kurdish and western investigators who have been operating secretly in Northern Iraq, for more than two years, collecting evidence of ISIS’ war crimes.


text: ISIL's atrocities against Yazidis were strongly condemned by prominent Islamic scholars and Muslim organizations.


text: On 7 August 2014, U.S. President Barack Obama ordered targeted airstrikes on IS militants and emergency air relief for the Yazidis. Airstrikes began on 8 August. (See American-led intervention in Iraq (2014–present)#Obama authorizes airstrikes.)


text: On 8 August 2014, the US asserted that the systematic destruction of the Yazidi people by the Islamic State was genocide.


text: President Barack Obama had authorized the attacks to protect Yazidis but also Americans and Iraqi minorities. President Obama gave an assurance that no troops would be deployed for combat. Along with the airstrikes of 9 August, the US airdropped 3,800 gallons of water and 16,128 MREs. Following these actions, the United Kingdom and France stated that they also would begin airdrops.


text: On 10 August 2014, at approximately 2:15 a.m. ET, the US carried out five additional airstrikes on armed vehicles and a mortar position, enabling 20,000–30,000 Yazidi Iraqis to flee into Syria and later be rescued by Kurdish forces. The Kurdish forces then provided shelter for the Yazidis in Dohuk.


text: On 13 August 2014, fewer than 20 United States Special Forces troops stationed in Irbil along with British Special Air Service troops visited the area near Mount Sinjar to gather intelligence and plan the evacuation of approximately 30,000 Yazidis still trapped on Mount Sinjar. One hundred and twenty-nine additional US military personnel were deployed to Irbil to assess and provide a report to President Obama. The United States Central Command also reported that a seventh airdrop was conducted and that to date, 114,000 meals and more than 35,000 gallons of water had been airdropped to the displaced Yazidis in the area.


text: In a statement on 14 August 2014, The Pentagon said that the 20 US personnel who had visited the previous day had concluded that a rescue operation was probably unnecessary since there was less danger from exposure or dehydration and the Yazidis were no longer believed to be at risk of attack from ISIL. Estimates also stated that 4,000 to 5,000 people remained on the mountain, with nearly half of which being Yazidi herders who lived there before the siege.


text: Kurdish officials and Yazidi refugees stated that thousands of young, elderly, and disabled individuals on the mountain were still vulnerable, with the governor of Kurdistan's Dahuk province, Farhad Atruchi, saying that the assessment was "not correct" and that although people were suffering, "the international community is not moving".


text: 30,000-40,000 Yazidis fled to Syria, 100,000 Yazidis took refuge in Kurdish controlled Zakho, Iraq. In Syria, the UNHCR provided material and transportation to Yazidi refugees and local Syrian communities cooked them meals. Turkey initially took in 2,000 Yazidis refugees in Silopi, where they were provided food and medical care, but some refugees were turned back. The Turkish Disaster Relief Agency (AFAD) also set up refugee camps in Zakho, Iraq. By 31 August, Turkey reportedly hosted 16,000 Yazidi refugees.


text: The US military air dropped food and water to Yazidis trapped on Mount Sinjar. "Today's Zaman" reported that Turkey also airdropped humanitarian aid to Yazidi refugees within Iraq.


text: Amal Clooney of the Center for Justice & Accountability (CJA), represented five Yazidi women before the United States District Court for the Eastern District of Virginia against Umm Sayyaf seeking prosecution of Sayyaf for her role in their enslavement. In 2021, German courts convicted ISIS women for their involvement in the enslavement of Yazidi women. A report by the Yazidi Justice Committee covered the allegation of countries, Turkey, Syria, and Iraq, for failing to prevent and punish the genocide.


text: United States Senators Amy Klobuchar and Lindsey Graham have called on United States President Joe Biden to help resettle Yazidi survivors of the Islamic State campaign of 2014-2017.


text: According to a report by Amnesty International, on January 25, 2015, members of a Yazidi militia attacked two Arab villages (Jiri and Sibaya) in the Sinjar region of northern Iraq, killing 21 civilians. The gunmen also kidnapped 40 other residents, 17 of whom are still missing and presumed dead.


title: Muscular Christianity

text: Muscular Christianity is a philosophical movement that originated in England in the mid-19th century, characterized by a belief in patriotic duty, discipline, self-sacrifice, masculinity, and the moral and physical beauty of athleticism.


title: Muscular Christianity

text: The movement came into vogue during the Victorian era as a method of building character in pupils at English public schools. It is most often associated with English author Thomas Hughes and his 1857 novel "Tom Brown's School Days", as well as writers Charles Kingsley and Ralph Connor. American President Theodore Roosevelt was raised in a household that practised Muscular Christianity and was a prominent adherent to the movement. Roosevelt, Kingsley, and Hughes promoted physical strength and health as well as an active pursuit of Christian ideals in personal life and politics. Muscular Christianity has continued through organizations that combine physical and Christian spiritual development. It is influential within both Catholicism and Protestantism.


title: Muscular Christianity

text: Until the Age of Enlightenment, the aesthetics of the body within Christianity were concerned chiefly with holy suffering. Asceticism, and the denial of bodily needs and beauty, was of interest to laity and clergy alike in Antiquity and the medieval period. A key tenet of asceticism is believing the flesh to be a distraction from divinity. Sects such as Catharism believed the flesh to be wholly corrupted.


title: Muscular Christianity

text: The Muscular Christianity movement was never officially organized. Instead, it was a cultural trend that manifested in different ways and was supported by various figures and churches. Muscular Christianity can be traced back to Paul the Apostle, who used athletic metaphors to describe the challenges of a Christian life. However, the explicit advocacy of sport and exercise in Christianity did not appear until 1762, when Rousseau's "" described physical education as important for the formation of moral character.


title: Muscular Christianity

text: The term "Muscular Christianity" became well known in a review by the barrister T. C. Sandars of Kingsley's novel "Two Years Ago" in the February 21, 1857 issue of the "Saturday Review". The term had appeared slightly earlier. Kingsley wrote a reply to this review in which he called the term "painful, if not offensive", but he later used it favorably on occasion.


title: Muscular Christianity

text: In addition to the beliefs stated above, Muscular Christianity preached the spiritual value of sports, especially team sports. As Kingsley said, "games conduce, not merely to physical, but to moral health". An article on a popular nineteenth-century Briton summed it up thus: "John MacGregor is perhaps the finest specimen of Muscular Christianity that this or any other age has produced. Three men seemed to have struggled within his breast—the devout Christian, the earnest philanthropist, the enthusiastic athlete."


title: Muscular Christianity

text: Despite having gained some support, the concept was still controversial. For one example, a reviewer mentioned "the ridicule which the 'earnest' and the 'muscular' men are doing their best to bring on all that is manly", though he still preferred earnestness' and 'muscular Christianity to eighteenth-century propriety. For another, a clergyman at Cambridge University horsewhipped another clergyman after hearing that he had said grace without mentioning Jesus because a Jew was present. A commentator said, "All this comes, we fear, of Muscular Christianity."


title: Muscular Christianity

text: Kingsley's contemporary Thomas Hughes is credited with helping to establish the main tenets of Muscular Christianity in "Tom Brown at Oxford", which were physical manliness, chivalry and masculinity of character. In "Tom Brown at Oxford", Hughes stated that "The Muscular Christians have hold of the old chivalrous and Christian belief, that a man's body is given to him to be trained and brought into subjection, and then used for the protection of the weak, the advancement of all righteous causes, and the subduing of the earth which God has given to the children of men." The notion of protecting the weak was related to contemporary English concerns over the plight of the poor, and Christian responsibility to one's neighbour.


title: Muscular Christianity

text: Richard Andrew Meyer, a professor of Baylor University, explains Thomas Hughes's six definitions of Muscular Christianity through six criteria. Meyer wrote a dissertation about Thomas Hughes's notion of Muscular Christianity by analyzing the career of Lance Armstrong. The criteria are "1) a man’s body is given to him (by God); 2) and to be trained; 3) and brought into subjection; 4) and then used for the protection of the weak; 5) for the advancement of all righteous causes; 6) and for the subduing of the earth which God has given to the children of men."


title: Muscular Christianity

text: The idea of Muscular Christianity first started in England amidst industrialization and urbanization. Like their American counterparts, Christians in England were worried about the decrease in manliness among their followers as a result of Puritan influences, including passive virtues like love and tenderness, causing Muscular Christianity to become a cultural trend. It was not started by any specific person, but rather supported by churches and many individual Christian figures, who then spread it to other congregations. At the time it was believed that physical training built stamina necessary to perform service for others and that physical strength led to moral strength and good character. Christians increasingly felt that athletics could be a good outlet for burning off steam rather than finding a less moral outlet. Sports also helped to recruit new members into the church. Churches began forming their own sports teams and had the associated facilities for them built in or around the churches themselves. This is how YMCA (Young Men's Christian Association) began in 1844 in London, although it did not yet have sports facilities until 1869 with the establishment of New York City's YMCA.


title: Muscular Christianity

text: These associations became very popular and YMCAs began appearing across the country. In 1894, an Anglican vicar, Reverend Arthur Osborne Montgomery Jay, built a gymnasium with a boxing ring in the basement of his East-End London church—Holy Trinity Shoreditch, organized a boxing club, and hosted large and popular boxing tournaments. Similar boxing outreach programs were established in the late-19th and early-20th centuries by Christian churches of various denominations in poor or working class areas of Britain and America. These outreach efforts drew in many men, particularly younger men, to not only box but to be ministered to as well.


title: Muscular Christianity

text: By 1901, Muscular Christianity was influential enough in England that one author could praise "the Englishman going through the world with rifle in one hand and Bible in the other" and add, "if asked what our muscular Christianity has done, we point to the British Empire." Muscular Christianity spread to other countries in the 19th century. It was well entrenched in Australian society by 1860, though not always with much recognition of the religious element.


title: Muscular Christianity

text: In the United States it appeared first in private schools and then in YMCA and in the preaching of evangelists such as Dwight L. Moody. Scholar Iren Annus linked the growth of Muscular Christianity in the United States to broader societal changes which were occurring throughout the country, including the emancipation of women and the influx of immigrants who worked blue-collar jobs while white Anglo-Saxon Protestant men became increasingly white-collar. These factors contributed to increasing anxiety over masculinity among white males in the United States. Parodied by Sinclair Lewis in "Elmer Gantry" (though he had praised Oberlin College YMCA for its "positive earnest muscular Christianity") and out of step with theologians such as Reinhold Niebuhr, its influence declined in American mainline Protestantism.


title: Muscular Christianity

text: Baylor University scholar Paul Putz summarises the purpose of Muscular Christianity as a mode to sanctify sports, positing that Muscular Christianity "sanctioned the physical activity of sports by giving it moral and religious value. Muscular Christians said that sports were not inherently sinful, nor were they simply entertainment and recreation; instead sports could be a way to develop and grow Christian character. You could become a better Christian "through" sport participation." An early pioneers of Muscular Christianity in the US was Amos Alonzo Stagg, a Yale-educated football coach, who in the 1880s sought to promote "Christian ideals" anchored in US middle class values such as "cooperation, belief in God, initiative, self-discipline, loyalty, respect for authority, courage, honesty."


title: Muscular Christianity

text: At the same time, it made a significant impact on Evangelicalism in the United States, and was promoted by organizations such as the Fellowship of Christian Athletes, Athletes in Action, and the Promise Keepers. Theodore Roosevelt was one of the most prominent adherents of Muscular Christianity in the United States. Roosevelt believed that, "There is only a very circumscribed sphere of usefulness for the timid good man", a sentiment echoed by many at the time. Followers of Muscular Christianity ultimately found that the only solution to this was to connect faith to the physicality of the body.


title: Muscular Christianity

text: An example sometimes given for US Muscular Christianity was the Men and Religion Forward Movement, organized by Fred Smith, a YMCA leader, in 1910. The movement held a mix of muscular, revivalistic and social gospel sensibilities, with work directed to evangelism, bible study, boys' work, mission, and social service. The organization hosted large revivals and campaigns throughout the US. Some 1.5 million men attended 7,000 events.


title: Muscular Christianity

text: Muscular Christianity's popularity declined notably after World War I, when the horrors of the war caused disillusionment with Christianity in general. It appeared to be "mindless strenuosity tied not to social reform but to what cereal king J. H. Kellogg called the new religion ‘of being good to yourself’", that is, "such newly accessible leisure-time pursuits as automobiling and listening to the radio."


title: Muscular Christianity

text: The spread of Muscular Christianity led to many changes within the Catholic Church. The services were changed to cater more towards men and priests were required to be of a certain "manly" stature. Priests who looked like this were thought to draw in more men like them. Protestant ministers in England and America argued that men were not truly Christians unless they were Muscular Christians. Muscular Christianity did later decline in some Protestant churches, but it never did disappear from the American religious landscape.


title: Muscular Christianity

text: Elwood Brown, physical director of the Manila chapter of the YMCA, heavily promoted Muscular Christianity in the Philippines, and co-founded the Far Eastern Championship Games which ran from 1914 to 1934. Japanese scholar Ikuo Abe argued that the modern sports ethic and sport culture in Japan was heavily influenced in its infancy by Christian missionaries and Western teachers during the 19th and 20th century. According to Abe, Japan's sport culture developed as a hybridization of Muscular Christianity and Bushido ethics. Muscular Christianity was also an influence on Swami Vivekananda's ideology of "muscular Hinduism" and Hindu nationalism, particularly his emphasis on physical prowess and masculinity.


title: Muscular Christianity

text: According to Peter Alegi, muscular Christianity reached Africa through colonial mission schools during the late 19th century. Sports were incorporated directly into many mission schools to promote muscular Christianity, as administrators and missionaries believed sports such as football shared many of the same values. The effect mission schools like Adams College in South Africa had was seen through the demographics of football players, as a significant number of members at the earliest sports clubs in South Africa were Christian Africans. Over time these practices moved away from specific sports and more towards general physical education.


title: Muscular Christianity

text: Muscular Christianity became widely noticed throughout Africa due to colonization. Men were meant to be the head of their households and it was viewed that this structure was deteriorating. It was the establishment of Western-style schools across the continent that brought about Muscular Christianity along with the introduction of European football teams. Soccer was thought to teach young boys self-restraint, fairness, honor, and success. It was also to develop them into disciplined, healthy, and moral citizens. The purpose behind these soccer clubs was not just to bring idealized traits to the young boys, but to make them into strong soldiers and advocates for the Western world. Missionary schools were among the first to incorporate football into their programs, to make sure every student was playing. This was to blend the African and Western culture to transition the African students more easily into the world of Christianity.


title: Muscular Christianity

text: Adams College, known as Amanzimtoti Training Institute before 1914, was one of the first and largest missionary schools in southern and central Africa. This school was important due to its football team, the Shooting Stars. This team was successful in competing against other teams throughout the area. Other missionary schools were known more for their success in other sports, like cricket or rugby.


title: Muscular Christianity

text: According to Nicholas Watson, the ideology of Muscular Christianity contributed to the development of the Olympic Games. Pierre de Coubertin, the founder of the modern Olympics, was greatly influenced by Muscular Christianity, and this was one of his primary inspirations alongside the Ancient Olympic Games of Greece.


title: Muscular Christianity

text: In the 21st century, there has been a resurgence in the popularity of Muscular Christianity, driven by the disproportionately high number of men becoming atheist or agnostic, and by a perceived "crisis of masculinity". In the United States, Muscular Christianity is best represented by athletes such as Tim Tebow, Manny Pacquiao, Josh Hamilton, and Jeremy Lin. These athletes frequently speak and write about their faith, and share their beliefs with their fans.


title: Muscular Christianity

text: New Calvinist pastors such as John Piper have pushed for an emphasis on a masculine Christianity and concept of Christ. Piper claimed that, "God revealed Himself in the Bible pervasively as king not queen; father not mother. Second person of the Trinity is revealed as the eternal Son not daughter; the Father and the Son create man and woman in His image and give them the name man, the name of the male." Because of this, Piper further claimed that "God has given Christianity a masculine feel."


title: Muscular Christianity

text: Michael Kimmel argues in his book "Manhood in America", that University of Notre Dame showcases Muscular Christianity because the school practices Catholicism. Male athletes on the varsity teams are thought to practice Thomas Hughes's six criteria for Muscular Christianity. Notre Dame's football team, for example, are Catholic men who believe their bodies are a gift from God. Therefore, they train their bodies in the name of God.


title: Household hardware

text: Household hardware (or simply, hardware) is equipment that can be touched or held by hand such as keys, locks, nuts, screws, washers, hinges, latches, handles, wire, chains, belts, plumbing supplies, electrical supplies, tools, utensils, cutlery and machine parts. Household hardware is typically sold in hardware stores.


title: Matt Olson

text: Matthew Kent Olson (born March 29, 1994) is an American professional baseball first baseman for the Atlanta Braves of Major League Baseball (MLB). He has previously played in MLB for the Oakland Athletics.


title: Matt Olson

text: Olson was drafted by the Athletics in the first round of the 2012 MLB draft, and made his MLB debut with them in 2016. After six seasons with the Athletics, he was traded to the Braves prior to the 2022 season and signed an eight-year contract extension. Olson has won two Gold Glove Awards, three Fielding Bible Awards, and was an All-Star in 2021.


title: Matt Olson

text: Olson is the second son of Scott and Lee Olson. Scott Olson served as his sons' youth baseball coach, until high school. Matt Olson's older brother, Zack, later pitched for the Harvard Crimson. Matt Olson attended Parkview High School in Lilburn, Georgia, where he played first base and pitched for the Parkview Panthers, leading them to back-to-back state championships in 2011 and 2012. Olson finished his high school career with a .431 batting average, 44 doubles, 45 home runs, 168 runs batted in (RBIs), and a fielding percentage over 0.980. He holds the Parkview High School and Gwinnett County records for wins and RBIs. His uniform number, No. 21, was retired by Parkview High School in February 2019. After graduating from high school with honors in 2012, Olson was drafted by the Oakland Athletics in the first round of the 2012 Major League Baseball draft. He had committed to play college baseball at Vanderbilt University, but ultimately decided to forgo his commitment to the Commodores and signed with Oakland.


title: Matt Olson

text: Olson made his professional debut that season with the Arizona League Athletics and also played for the Vermont Lake Monsters that first season. In total, he played in 50 games and hit .282/.352/.521 with nine home runs and 45 RBIs.


title: Matt Olson

text: In 2013, Olson played with the Beloit Snappers. In 134 games he hit .225/.326/.435 though still hit 23 home runs while driving in 93 RBIs.


title: Matt Olson

text: Olson played the 2014 season with the Stockton Ports. Throughout the season he was among the home run leaders in Minor League Baseball, as during the season he batted .262/.404/.543 with 37 home runs and 97 RBIs in 138 games, leading all minor leaguers with 500 or more plate appearances with a walk percentage of 18.5%. He played the 2015 season with the Midland RockHounds where he hit .249 with 17 home runs and 75 RBIs in 133 games. Olson played the entire 2016 minor league season with the Nashville Sounds. In 131 games, he batted .235 with 17 home runs and 60 RBIs.


title: Matt Olson

text: The Athletics purchased Olson's contract on September 12, 2016, and he was called up to the major league club. He played in 11 games for Oakland. In 2017, Olson split time between Nashville and Oakland. In 79 games for Nashville he batted .272 with 23 home runs and 60 RBIs, and in 59 games for Oakland, he hit .259 with 24 home runs and 45 RBIs. With Oakland he hit 13 in the month of September (a rookie record) and one in five straight games. It was tied for third-most home runs in a player's first 65 career games in MLB history.


title: Matt Olson

text: Olson spent all of 2018 with Oakland, playing in all 162 games. On April 18, Olson hit his first career walk-off, an RBI single to secure a 12–11 comeback win over the Chicago White Sox. His first walk-off home run came in a game against the Houston Astros on August 17. On September 26, he hit his first career grand slam in a 9–3 victory over the Seattle Mariners. Olson finished his 2018 campaign batting .247 with 29 home runs and 84 RBIs. He also won his first Gold Glove Award, leading all AL first basemen with 14 defensive runs saved and an 11.6 ultimate zone rating.


title: Matt Olson

text: Olson played in both games of the 2019 Opening Series in Tokyo, Japan. During the second game on March 21, he was removed from the game after he felt pain in his right hand. The next day, he underwent successful surgery to remove the hamate bone from the hand, returning to the lineup on May 7. He batted .267/.351/.545 for the 2019 season. On defense, he had a 13 Defensive Runs Saved (DRS) rating, the best in the major leagues among first basemen. He received his second consecutive Gold Glove Award for his defensive performance.


title: Matt Olson

text: On July 24, 2020, Olson hit the first Opening Day walk-off grand slam since 1986. Olson struggled in the 2020 season shortened by the COVID-19 pandemic, batting .195, although he led the Oakland A's in games played (60), home runs (14) and RBIs (42).


title: Matt Olson

text: In 2021, Olson led the team in games played (156), hits (153), home runs (39), RBIs (111), walks (88) ranked second for batting average (.271) and on-base percentage (.371) and led the team in slugging percentage (.540). Olson was also selected for the 2021 Major League Baseball All-Star Game to represent the American League and participated in the 2021 Major League Baseball Home Run Derby. Olson was a finalist for the Silver Slugger Award and for the Gold Glove Award.


title: Matt Olson

text: On March 14, 2022, the Athletics traded Olson to the Atlanta Braves in exchange for Cristian Pache, Shea Langeliers, Joey Estes, and Ryan Cusick. The next day, Olson signed an 8-year contract extension worth $168 million. At the time it was announced, the extension was the largest contract in team history, surpassing an eight-year deal worth $135 million signed by Freddie Freeman in 2014. Its length and total value were exceeded by a contract given to teammate Austin Riley later that season. Olson primarily wore the number 28 jersey with the Oakland Athletics, and used the same number upon signing with the Braves. Olson started wearing number 28 upon his 2017 major league promotion to Oakland because his preferred number (21), which he wore to honor Jeff Francoeur, was then being used by Stephen Vogt. Olson was one of two players in Major League Baseball to appear in all 162 games of the 2022 season, alongside teammate Dansby Swanson, who made 162 starts.


title: Rinus Michels

text: Marinus Jacobus Hendricus Michels (; 9 February 1928 – 3 March 2005) was a Dutch football player and coach. He played his entire career for AFC Ajax, which he later managed, and played for and later managed the Netherlands national team for four spells. He is regarded as one of the greatest managers of all-time.


title: Rinus Michels

text: Michels became most notable for his coaching achievements; he won the European Cup with Ajax and the Spanish league with Barcelona, and had four tenures as coach of the Netherlands national team, who he led to reach the final of the 1974 FIFA World Cup and to win the 1988 UEFA European Championship.


title: Rinus Michels

text: He is credited with the invention of a major football playing style and set of tactics known as "Total Football" in the 1970s. He was named Coach of the Century by FIFA in 1999, in 2007 the greatest post-war football coach by "The Times" and in 2019 the greatest coach in the history of football by France Football.


title: Rinus Michels

text: Michels was born in Amsterdam and grew up at the Olympiaweg, a street near the Olympic Stadium. He celebrated his ninth birthday on 9 February 1937, when he received a pair of football boots and an Ajax jersey. Moments later, he was playing with his father at a small field near their home. Via Joop Köhler, a friend of the family who was commissioner at Ajax, Michels was introduced to the club and became a junior member in 1940. When World War II started, and especially during the Dutch famine of 1944–45, Michels' career was set on hold.


title: Rinus Michels

text: French club Lille had also wanted to contract Michels, but a playing career abroad did not materialize as the Royal Netherlands Army did not allow him to go because he had to serve on active duty.


title: Rinus Michels

text: On 9 June 1946, Michels was invited into Ajax's first team squad to replace the injured Han Lambregt. In his debut, Ajax beat ADO 8–3 and Michels scored five times. That season, Ajax won their 14th division championship and a year later they won the Dutch national championship. Although there were doubts about Michels' technical skills, team members like Cor van der Hart and captain Joop Stoffelen were enthusiastic about his strength and heading capabilities. Indeed, Michels was characterized for his hard work rather than for his technical qualities.


title: Rinus Michels

text: He went on to become a regular for the club, and between 1946 and 1958, he appeared in 264 league matches for Ajax, in which he scored 122 goals. In 1958, four years after the introduction of professional football in the Netherlands and one year after winning his second league title, he was forced to end his career due to a back injury.


title: Rinus Michels

text: Michels' international playing career with the Netherlands national team lasted five matches, making his debut on 8 June 1950 away to Sweden, a 4–1 defeat. He also lost all of his remaining matches as an "Oranje" player, 4–1 to Finland, 4–0 to Belgium, 6–1 to Sweden and 3–1 to Switzerland.


title: Rinus Michels

text: Michels returned to Ajax as head coach in 1965. Under his tenure and along with great players such as Johan Cruyff and Johan Neeskens, Ajax went from relegation candidates to a team that won the national championship four times and the KNVB Cup three times in the following six years. In 1969, they reached the final of the European Cup for the first time, being defeated 4–1 by Italian side Milan. In 1971, he managed Ajax to the first of three consecutive European Cups, a feat only achieved previously by the great Real Madrid team of Alfredo Di Stéfano and Ferenc Puskás. While at Ajax, Michels modernized the game by introducing what became known as "Total Football" and using the Offside trap. He then moved to Barcelona in the second part of 1971, being joined by Johan Cruyff in 1973. With Michels and Cruyff, the team won the Primera División title in 1974 before Michels became manager of the Dutch national team.


title: Rinus Michels

text: Michels was appointed national coach by the Royal Dutch Football Association (KNVB) after the Netherlands had qualified for the 1974 FIFA World Cup. His first game as the Netherlands' coach was on 27 March 1974 in a 1–1 draw against Austria. At the finals tournament in Germany, their third ever World Cup participation, the Dutch impressed many observers with their style of play which was backed up by their results; they won their first round group, then in the second round group they defeated Argentina and the defending world champions Brazil, and reached the final after five wins and one draw, with 14 goals scored and only one conceded in six matches. At that point, Michels was undefeated in nine matches as the Netherlands' coach. The Netherlands scored first against West Germany in the final, but the host team came back to defeat them 2–1, ending their run. That match was the last of Michels' first tenure in charge of the Dutch team, which he would return to coach ten years later.


title: Rinus Michels

text: Michels later moved on to the United States where he coached in the ill-fated North American Soccer League. He ended his club coaching career with Bayer Leverkusen in 1989. He had his "jour de gloire", however, when he coached the Dutch team to European glory at the 1988 UEFA European Championship.


title: Rinus Michels

text: Michels returned to coach the team for the Euro 1988 tournament. After losing the first group match against the Soviet Union (1–0), the Netherlands went on to qualify for the semi-final by defeating England 3–1 (with a hat-trick by the tournament's top scorer Marco van Basten), and the Republic of Ireland (1–0). For many Dutch football supporters, the most important match in the tournament was the semi-final against West Germany, the host country, considered a revenge for the lost 1974 World Cup final (also in West Germany). Michels said after the match, "We won the tournament, but we all know that the semi-final was the real final." Van Basten, who would later become national team coach, scored in the 89th minute of the game to sink the German side. The game is also remembered for its post-match shenanigans, including Ronald Koeman, who, in front of the German supporters, provocatively pretended to wipe his backside with the shirt of Olaf Thon as if it were toilet paper, an action Koeman later did not regret. The Netherlands won the final with a convincing victory over the Soviet Union, a rematch on the round robin game, through a header by Ruud Gullit and a remarkable volley by Van Basten. This was the national team's first, and to date only, major tournament win and it restored them to the forefront of international football after almost a decade in the wilderness for almost three years to come.


title: Rinus Michels

text: Michels died on 3 March 2005 at a hospital in Aalst, Belgium, after a heart surgery in the hospital of Gareth, Spain (his second since 1986).


title: Rinus Michels

text: Regarded as one of the greatest managers of all time, Rinus Michels's tactics and "Total football" philosophy were influenced by his time playing under English manager Jack Reynolds at Ajax, who had implemented a similar playing style with the club to great success in the 1940s. When Michels himself later became manager of Ajax in 1965, he further developed this style around the team's main forward Johan Cruyff. Although Cruyff was seemingly fielded as centre forward, Michels encouraged Cruyff to roam freely around the pitch, using his technical ability, creativity, and intelligence to exploit the weaknesses in the opposition and create space and chances in addition to scoring goals. Cruyff's teammates also supported him by playing him in a similar manner, regularly switching positions to ensure that the tactical roles in the team were consistently filled. This role has retroactively been compared to the "false 9" position in contemporary football.


title: Rinus Michels

text: The major component of football was the use of space, and the need to consistently create it. Former Ajax defender Barry Hulshoff described it as "[the thing] we discussed the whole time. Cruyff always talked about where to run and where to stand, and when not to move". He further elaborated that position switching was only made possible due to apt spatial awareness. He also described Total Football being proactive, as well as highlighting the use of pressing, which would be used to win back the ball or put the opposition under considerable pressure. Another aspect of the system was the use of the offside trap. Under Michels's system, Ajax enjoyed a highly successful period, winning, winning four Eredivisie titles, three KNVB Cups, and one European Cup.


title: Rinus Michels

text: The rise of Total Football and its attacking qualities were also linked with the demise of the more defensive–minded "Catenaccio", a system reliant heavily on man-marking and counter–attacking, which was promoted most prominently by Italian sides Internazionale and Milan during the 1960s under Helenio Herrera and Nereo Rocco Respectively. Unlike previous systems, in "Total Football", no out–field player was fixed in their nominal role, which exposed weaknesses in the "catenaccio" tactical system; any player could assume the role of a forward, midfielder, or defender, at any given time depending on the circumstances. Due to players often switching positions with one another, man-marking strategies, such as "catenaccio", were no longer effective at coping with this highly fluid tactical system. Despite previously losing out 4–1 to Milan in the 1969 European Cup Final, who were managed by Rocco, a manager known for his defensive catenaccio strategy, in 1972, Michels's Ajax defeated Inter 2–0 in the European Cup final, and Dutch newspapers subsequently announced the "destruction of "Catenaccio"" at the hands of "Total Football". The following year, Ajax defeated Cesare Maldini's Milan 6–0 in the second leg of the European Super Cup, in a match in which the defensive "catenaccio" system employed by Milan was unable to stop Ajax, which saw the Dutch side win the title 6–1 on aggregate; this was the worst defeat for an Italian team in an UEFA competition final.


title: Rinus Michels

text: Total football also had some weaknesses, however, which were notably exploited in the final of the 1974 FIFA World Cup by West Germany. Michels and Cruyff saw their ability to introduce playmaking stifled in the second half of the match by the effective marking of Berti Vogts. This allowed Franz Beckenbauer, Uli Hoeneß, and Wolfgang Overath to gain a stronghold in midfield, thus, enabling West Germany to win 2–1. Moreover, as man-marking alone was insufficient to cope with the fluidity of "total football", Italian coaches consequently began to create a new tactical system that mixed man-marking with zonal defence in order to counter this strategy, which came to be known as "zona mista" ("mixed zone," in Italian), or "gioco all'italiana" ("gameplay in the Italian manner," in Italian), in Italian football, as it mixed elements of Italian "catenaccio" (man-marking) with elements of "total football" (zonal marking), with Giovanni Trapattoni as one its main and most successful proponents from the 1970s onward.


title: Rinus Michels

text: Michels became known as a person who was keen on his money and did not want to spend much of it. A common joke in the Ajax changing rooms in those days was, "Does anybody actually know the color of Michels' wallet?". His IQ was high and during foreign trips he always brought a book with him, which he wanted to have read completely before coming home. He was known as someone who did not need anybody and who felt happy on his own, but sometimes he joined his teammates and shared their enthusiastic friendships. At the celebrations of Ajax' 50th birthday in 1950, he was the organizer of the humoristic show that was held and during traditional parties he and his friend Hans Boskamp climbed up the stages to sing some duets. After matches, he was always soaping himself down in the showers of the changing rooms as well, even when the match was lost.


title: Rinus Michels

text: Michels was also known as a practical joker. At a hotel he once borrowed a fur coat of a lady and pretended to be a lady to his teammates. During a training session in Lille, the players went fishing and Michels, who did not enjoy himself, jumped into the water.


title: Rinus Michels

text: Due to his authoritarian style as coach, Michels was called "The General". He said, "Professional football is something like war. Whoever behaves too properly, is lost." This has often been misquoted as "Football is war." Michels felt the quote was taken out of context as he did not intend to equate war with football. Michels was named coach of the century by FIFA in 1999.


title: Lake Itasca

text: Lake Itasca is a small glacial lake, approximately in area. Located in southeastern Clearwater County, in the Headwaters area of north central Minnesota, it is notable for being the headwater of the Mississippi River. The lake is in Itasca State Park. It has an average depth of and is above sea level.


title: Lake Itasca

text: The Ojibwe name for "Lake Itasca" is "Omashkoozo-zaaga'igan" (Elk Lake); this was changed by Henry Schoolcraft to "Itasca", coined from a combination of the Latin words "veritas caput" ("true head [of the Mississippi]"). It is one of several examples of pseudo-Indian place names created by Schoolcraft.


title: Lake Itasca

text: It is the primary source of the Mississippi River which flows 2,340 mi (3,770 km) to the Gulf of Mexico. There are several tributaries that flow (most or all of the year) into the lake, one of which, by most modern definitions, as with the Nile River and Amazon River, would be considered the actual source, though less dramatic than the lake's outflow. Henry Schoolcraft identified Lake Itasca as the river's primary source in 1832. He had been part of a previous expedition in 1820 led by General Lewis Cass that had named nearby Cass Lake (which is downstream from Itasca) as the source of the river. There exists a dissenting claim that fur trader William Morrison was the first person to discover the lake and identified it as the source of the Mississippi in 1804.


title: Lake Itasca

text: The western arm of the lake is fed by two streams on its south end. Nicollet Creek starts in a nearby spring. Another small stream leads into Itasca from Elk Lake, which in turn is fed by two other streams. The Ojibwa called Elk Lake and the stream "Bekegamaag-zaaga'igan" and "Bekegamaag-ziibi" (Sidelake Lake and Sidelake River), respectively. In 1887 Williard Glazier promoted a campaign to consider Elk Lake, which he called Glazier Lake, as the true source of the Mississippi. Its longest tributary originates at Little Elk Lake, which is 100 ft (30 m) higher in elevation and 11 km upstream from the Lake Itasca outflow, at and in the Mississippi watershed.


title: Lake Itasca

text: Jacob V. Brower, a land surveyor and president of the Minnesota Historical Society, after spending five months exploring the lakes, claimed that the lakes and streams further south of Lake Itasca were not the true source of the Mississippi because they were "too small". Modern explorers and geographers, however, have used the tiniest trickles of water to determine the source of the Amazon, Nile, and other rivers. Brower was to campaign aggressively to save the lake from logging. On April 21, 1891, the Minnesota Legislature officially made it a state park by a margin of one vote. Brower is now called the "Father of Lake Itasca" and the visitor center is named in his honor.


title: Lake Itasca

text: The channel of the Mississippi as it emerges from the lake was bulldozed in the 1930s by the Civilian Conservation Corps, to create a more "pleasant experience" for visitors. The project included the draining of the surrounding swamp, the digging of a new channel, and the installation of a man-made rock rapids. The rocks are used by tourists for walking across the Mississippi River.


title: Lake Itasca

text: The lake is home to the University of Minnesota's Itasca Biological Station and Laboratories campus, which offers spring and summer courses and field research work year-round. The campus was established in 1909. Some of these buildings date from the 1930s and 40s, while others, including the largest building the Biome Center, were built more recently. The current Director of the biological station is Jonathan Schilling.


title: Lake Itasca

text: The Lake Itasca region claims a unique location, not only at the headwaters of the Mississippi River and amidst 25% of the old growth forest of Minnesota, but also at the juncture of the three great habitats of North America: the Great Plains, the Deciduous Forest of the south, and the Coniferous Forest of the north. Remnants of all three may be observed in the park.


title: Lake Itasca

text: The unique geography of the Lake Itasca region has found its way onto the classical music concert stage. Composer Ferde Grofe depicted the birthplace of the Mississippi River and the Native Americans who reside there in his popular classical epic the "Mississippi Suite".


title: Relish

text: A relish is a cooked and pickled product made of chopped vegetables, fruits or herbs and is a food item typically used as a condiment to enhance a staple. Examples are chutneys and the North American relish, a pickled cucumber jam eaten with hot dogs or hamburgers. In North America, the word "relish" is frequently used to describe a single variety of finely-chopped pickled cucumber relish, such as pickle, dill and sweet relishes.


title: Relish

text: Relish generally consists of discernible vegetable or fruit pieces in a sauce, although the sauce is subordinate in character to the vegetable or fruit pieces. Herbs may also be used, and some relishes, such as chermoula, are prepared entirely using herbs and spices. Relish can consist of a single type or a combination of vegetables and fruit, which may be coarsely or finely chopped; its texture will vary depending on the slicing style used for these solid ingredients, but generally a relish is not as smooth as a sauce-type condiment such as ketchup. Relish typically has a strong flavor that complements or adds to the primary food item with which it is served.


title: Relish

text: In the United States, the most common commercially available relishes are made from pickled cucumbers and are known in the food trade as pickle relishes. Pickle relish is one of the most commonly used spreads in the U.S. Two variants of this are hamburger relish (pickle relish in a ketchup base or sauce) and hot dog relish (pickle relish in a mustard base or sauce). Another readily available commercial relish in the U.S. is corn (maize) relish. Heinz, Vlasic, and Claussen are well known in the U.S. as producers of pickled cucumbers and pickle relishes. Chicago-style relish is a sweet pickle relish that is a standard ingredient on the Chicago-style hot dog. Pickle relish is an important ingredient in many varieties of the U.S. version of tartar sauce.


title: Collaborative filtering

text: Collaborative filtering (CF) is a technique used by recommender systems. Collaborative filtering has two senses, a narrow one and a more general one.


title: Collaborative filtering

text: In the newer, narrower sense, collaborative filtering is a method of making automatic predictions (filtering) about the interests of a user by collecting preferences or taste information from many users (collaborating). The underlying assumption of the collaborative filtering approach is that if a person "A" has the same opinion as a person "B" on an issue, A is more likely to have B's opinion on a different issue than that of a randomly chosen person. For example, a collaborative filtering recommendation system for preferences in television programming could make predictions about which television show a user should like given a partial list of that user's tastes (likes or dislikes). Note that these predictions are specific to the user, but use information gleaned from many users. This differs from the simpler approach of giving an average (non-specific) score for each item of interest, for example based on its number of votes.


title: Collaborative filtering

text: In the more general sense, collaborative filtering is the process of filtering for information or patterns using techniques involving collaboration among multiple agents, viewpoints, data sources, etc. Applications of collaborative filtering typically involve very large data sets. Collaborative filtering methods have been applied to many different kinds of data including: sensing and monitoring data, such as in mineral exploration, environmental sensing over large areas or multiple sensors; financial data, such as financial service institutions that integrate many financial sources; or in electronic commerce and web applications where the focus is on user data, etc. The remainder of this discussion focuses on collaborative filtering for user data, although some of the methods and approaches may apply to the other major applications as well.


title: Collaborative filtering

text: The growth of the Internet has made it much more difficult to effectively extract useful information from all the available online information. The overwhelming amount of data necessitates mechanisms for efficient information filtering. Collaborative filtering is one of the techniques used for dealing with this problem.


title: Collaborative filtering

text: The motivation for collaborative filtering comes from the idea that people often get the best recommendations from someone with tastes similar to themselves. Collaborative filtering encompasses techniques for matching people with similar interests and making recommendations on this basis.


title: Collaborative filtering

text: Collaborative filtering algorithms often require (1) users' active participation, (2) an easy way to represent users' interests, and (3) algorithms that are able to match people with similar interests.


title: Collaborative filtering

text: A key problem of collaborative filtering is how to combine and weight the preferences of user neighbors. Sometimes, users can immediately rate the recommended items. As a result, the system gains an increasingly accurate representation of user preferences over time.


title: Collaborative filtering

text: Collaborative filtering systems have many forms, but many common systems can be reduced to two steps:


title: Collaborative filtering

text: This falls under the category of user-based collaborative filtering. A specific application of this is the user-based Nearest Neighbor algorithm.


title: Collaborative filtering

text: Alternatively, item-based collaborative filtering (users who bought x also bought y), proceeds in an item-centric manner:


title: Collaborative filtering

text: Another form of collaborative filtering can be based on implicit observations of normal user behavior (as opposed to the artificial behavior imposed by a rating task). These systems observe what a user has done together with what all users have done (what music they have listened to, what items they have bought) and use that data to predict the user's behavior in the future, or to predict how a user might like to behave given the chance. These predictions then have to be filtered through business logic to determine how they might affect the actions of a business system. For example, it is not useful to offer to sell somebody a particular album of music if they already have demonstrated that they own that music.


title: Collaborative filtering

text: Relying on a scoring or rating system which is averaged across all users ignores specific demands of a user, and is particularly poor in tasks where there is large variation in interest (as in the recommendation of music). However, there are other methods to combat information explosion, such as web search and data clustering.


title: Collaborative filtering

text: The memory-based approach uses user rating data to compute the similarity between users or items. Typical examples of this approach are neighbourhood-based CF and item-based/user-based top-N recommendations. For example, in user based approaches, the value of ratings user "u" gives to item "i" is calculated as an aggregation of some similar users' rating of the item:


title: Collaborative filtering

text: where "U" denotes the set of top "N" users that are most similar to user "u" who rated item "i". Some examples of the aggregation function include:


title: Collaborative filtering

text: The neighborhood-based algorithm calculates the similarity between two users or items, and produces a prediction for the user by taking the weighted average of all the ratings. Similarity computation between items or users is an important part of this approach. Multiple measures, such as Pearson correlation and vector cosine based similarity are used for this.


title: Collaborative filtering

text: The user based top-N recommendation algorithm uses a similarity-based vector model to identify the "k" most similar users to an active user. After the "k" most similar users are found, their corresponding user-item matrices are aggregated to identify the set of items to be recommended. A popular method to find the similar users is the Locality-sensitive hashing, which implements the nearest neighbor mechanism in linear time.


title: Collaborative filtering

text: The advantages with this approach include: the explainability of the results, which is an important aspect of recommendation systems; easy creation and use; easy facilitation of new data; content-independence of the items being recommended; good scaling with co-rated items.


title: Collaborative filtering

text: There are also several disadvantages with this approach. Its performance decreases when data gets sparse, which occurs frequently with web-related items. This hinders the scalability of this approach and creates problems with large datasets. Although it can efficiently handle new users because it relies on a data structure, adding new items becomes more complicated since that representation usually relies on a specific vector space. Adding new items requires inclusion of the new item and the re-insertion of all the elements in the structure.


title: Collaborative filtering

text: In this approach, models are developed using different data mining, machine learning algorithms to predict users' rating of unrated items. There are many model-based CF algorithms. Bayesian networks, clustering models, latent semantic models such as singular value decomposition, probabilistic latent semantic analysis, multiple multiplicative factor, latent Dirichlet allocation and Markov decision process based models.


title: Collaborative filtering

text: Through this approach, dimensionality reduction methods are mostly being used as complementary technique to improve robustness and accuracy of memory-based approach. In this sense, methods like singular value decomposition, principal component analysis, known as latent factor models, compress user-item matrix into a low-dimensional representation in terms of latent factors. One advantage of using this approach is that instead of having a high dimensional matrix containing abundant number of missing values we will be dealing with a much smaller matrix in lower-dimensional space. A reduced presentation could be utilized for either user-based or item-based neighborhood algorithms that are presented in the previous section. There are several advantages with this paradigm. It handles the sparsity of the original matrix better than memory based ones. Also comparing similarity on the resulting matrix is much more scalable especially in dealing with large sparse datasets.


title: Collaborative filtering

text: A number of applications combine the memory-based and the model-based CF algorithms. These overcome the limitations of native CF approaches and improve prediction performance. Importantly, they overcome the CF problems such as sparsity and loss of information. However, they have increased complexity and are expensive to implement. Usually most commercial recommender systems are hybrid, for example, the Google news recommender system.


title: Collaborative filtering

text: In recent years a number of neural and deep-learning techniques have been proposed. Some generalize traditional Matrix factorization algorithms via a non-linear neural architecture, or leverage new model types like Variational Autoencoders.


title: Collaborative filtering

text: While deep learning has been applied to many different scenarios: context-aware, sequence-aware, social tagging etc. its real effectiveness when used in a simple collaborative recommendation scenario has been put into question. A systematic analysis of publications applying deep learning or neural methods to the top-k recommendation problem, published in top conferences (SIGIR, KDD, WWW, RecSys), has shown that on average less than 40% of articles are reproducible, with as little as 14% in some conferences. Overall the study identifies 18 articles, only 7 of them could be reproduced and 6 of them could be outperformed by much older and simpler properly tuned baselines. The article also highlights a number of potential problems in today's research scholarship and calls for improved scientific practices in that area. Similar issues have been spotted also in sequence-aware recommender systems.


title: Collaborative filtering

text: Many recommender systems simply ignore other contextual information existing alongside user's rating in providing item recommendation. However, by pervasive availability of contextual information such as time, location, social information, and type of the device that user is using, it is becoming more important than ever for a successful recommender system to provide a context-sensitive recommendation. According to Charu Aggrawal, "Context-sensitive recommender systems tailor their recommendations to additional information that defines the specific situation under which recommendations are made. This additional information is referred to as the context."


title: Collaborative filtering

text: Taking contextual information into consideration, we will have additional dimension to the existing user-item rating matrix. As an instance, assume a music recommender system which provide different recommendations in corresponding to time of the day. In this case, it is possible a user have different preferences for a music in different time of a day. Thus, instead of using user-item matrix, we may use tensor of order 3 (or higher for considering other contexts) to represent context-sensitive users' preferences.


title: Collaborative filtering

text: In order to take advantage of collaborative filtering and particularly neighborhood-based methods, approaches can be extended from a two-dimensional rating matrix into a tensor of higher order. For this purpose, the approach is to find the most similar/like-minded users to a target user; one can extract and compute similarity of slices (e.g. item-time matrix) corresponding to each user. Unlike the context-insensitive case for which similarity of two rating vectors are calculated, in the context-aware approaches, the similarity of rating matrices corresponding to each user is calculated by using Pearson coefficients. After the most like-minded users are found, their corresponding ratings are aggregated to identify the set of items to be recommended to the target user.


title: Collaborative filtering

text: The most important disadvantage of taking context into recommendation model is to be able to deal with larger dataset that contains much more missing values in comparison to user-item rating matrix. Therefore, similar to matrix factorization methods, tensor factorization techniques can be used to reduce dimensionality of original data before using any neighborhood-based methods.


title: Collaborative filtering

text: Unlike the traditional model of mainstream media, in which there are few editors who set guidelines, collaboratively filtered social media can have a very large number of editors, and content improves as the number of participants increases. Services like Reddit, YouTube, and Last.fm are typical examples of collaborative filtering based media.


title: Collaborative filtering

text: One scenario of collaborative filtering application is to recommend interesting or popular information as judged by the community. As a typical example, stories appear in the front page of Reddit as they are "voted up" (rated positively) by the community. As the community becomes larger and more diverse, the promoted stories can better reflect the average interest of the community members.


title: Collaborative filtering

text: Wikipedia is another application of collaborative filtering. Volunteers contribute to the encyclopedia by filtering out facts from falsehoods.


title: Collaborative filtering

text: Another aspect of collaborative filtering systems is the ability to generate more personalized recommendations by analyzing information from the past activity of a specific user, or the history of other users deemed to be of similar taste to a given user. These resources are used as user profiling and helps the site recommend content on a user-by-user basis. The more a given user makes use of the system, the better the recommendations become, as the system gains data to improve its model of that user.


title: Collaborative filtering

text: A collaborative filtering system does not necessarily succeed in automatically matching content to one's preferences. Unless the platform achieves unusually good diversity and independence of opinions, one point of view will always dominate another in a particular community. As in the personalized recommendation scenario, the introduction of new users or new items can cause the cold start problem, as there will be insufficient data on these new entries for the collaborative filtering to work accurately. In order to make appropriate recommendations for a new user, the system must first learn the user's preferences by analysing past voting or rating activities. The collaborative filtering system requires a substantial number of users to rate a new item before that item can be recommended.


title: Collaborative filtering

text: In practice, many commercial recommender systems are based on large datasets. As a result, the user-item matrix used for collaborative filtering could be extremely large and sparse, which brings about challenges in the performance of the recommendation.