title: Kashiwazaki-Kariwa Nuclear Power Plant

text: The KK plant was 19 kilometers away from the epicenter of the magnitude 6.6 2007 Chūetsu offshore earthquake, which took place 10:13 a.m., July 16, 2007. Peak ground acceleration of 6.8 m/s (0.69 "g") was recorded in Unit 1 in the east–west direction, above the design specification for safe shutdown of 4.5 m/s, and well above the rapid restart specification for key equipment in the plant of 2.73 m/s. Units 5 and 6 also recorded shaking over this limit. Shaking of 20.58 m/s was recorded in the turbine building of Unit 3.


title: Kashiwazaki-Kariwa Nuclear Power Plant

text: Those nearby saw black smoke which was later confirmed to be an electric transformer that had caught fire at Unit 3. The fire was put out by noon on the day of the quake, about 2 hours after it started. The 3-story transformer building was extensively charred.


title: Kashiwazaki-Kariwa Nuclear Power Plant

text: Reactor units 3, 4, and 7 all automatically powered down safely in response to the quake. Unit 2 was in startup mode and not online. Units 1, 5, and 6 were already shut down for inspection at the time. TEPCO was ready to restart some of the units as of the next day, but the trade ministry ordered the plant to remain idle until additional safety checks could be completed. On Wednesday, July 18, the mayor of Kashiwazaki ordered operations at the plant to be halted until its safety could be confirmed. The "Nikkei" reported that government safety checks could delay the restart for over a year, without stating the source of the information. For comparison, in 2005, a reactor at the Onagawa Nuclear Power Plant was closed for five months following an earthquake.


title: Kashiwazaki-Kariwa Nuclear Power Plant

text: The International Atomic Energy Agency (IAEA) offered to inspect the plant, which was initially declined. The governor of Niigata prefecture then sent a petition to Shinzo Abe. On Sunday, July 22, 2007, the Nuclear and Industrial Safety Agency (NISA) announced that it would allow inspectors from the United Nations to review the damage.


title: Kashiwazaki-Kariwa Nuclear Power Plant

text: A team from the IAEA carried out a four-day inspection, as investigations by Japan's Nuclear and Industrial Safety Agency (NISA), Nuclear Safety Commission (NSC) and the Tokyo Electric Power Company (TEPCO) continued. The team of the IAEA confirmed that the plant had "shut down safely" and that "damage appears less than expected." On August 19, the IAEA reported that, for safety-related and nuclear components, "no visible significant damage has been found" although "nonsafety related structures, systems and components were affected by significant damage".


title: Kashiwazaki-Kariwa Nuclear Power Plant

text: The official report issued by the IAEA stated that the plant "behaved in a safe manner" after a 4-day inspection. Other observations were:


title: Kashiwazaki-Kariwa Nuclear Power Plant

text: External inspections of the plant were planned to be completed by the end of July 2008. The schedule was confirmed on 10 July 2008 by the site superintendent, Akio Takahashi. On July 15, Akira Amari said his ministry was also continuing their own tests. An IAEA workshop in June 2008 recognized that the earthquake exceeded the "seismic input" used in the design in that plant, and that regulations played a critical role in keeping the plant safe. However, TEPCO determined that significant upgrades were required to cope with the improved understanding of the seismic environment and possible shaking effects at the plant site.


title: Kashiwazaki-Kariwa Nuclear Power Plant

text: The IAEA sent a team for a follow-up visit in January 2008. They concluded that much high-quality inspection work had been undertaken and noted the likely improvements to nuclear seismic design worldwide that may result from this process. An additional visit from an IAEA team of 10 experts occurred in December 2008, noting that the "unexpectedly large ground motions" were now well understood and could be protected against, and further confirming the safe performance of the plant during the quake.


title: Kashiwazaki-Kariwa Nuclear Power Plant

text: Initially, it was thought that some water (estimated to be about 1.5 L) from the spent fuel pool leaked into the Sea of Japan as a result of the quake. Later, more detailed reports confirmed a number of releases, though most of them were far less active than common natural radiation sources. According to the NISA, this was the first time a release of radioactive material happened as a result of an earthquake.


title: Kashiwazaki-Kariwa Nuclear Power Plant

text: About 400 drums containing low-level nuclear waste stored at the plant were knocked over by the aftershocks, 40 losing their lids. Company officials reported on July 17 that traces of the radioactive materials cobalt-60, iodine, and chromium-51 had been released into the atmosphere, presumably from the containers losing their lids.


title: Kashiwazaki-Kariwa Nuclear Power Plant

text: Criticisms of the company's response to the event included the time it took the company to report events and the certainty with which they were able to locate the source of various problems. TEPCO's president made a comment the site was a "mess" after visiting post-quake. While the reported amount of leaked radioactivity remained far below what poses a danger to the public, details changed multiple times in the few days after the quake and attracted significant media attention. After the quake, TEPCO was supposedly investigating 50 separate cases of "malfunctioning and trouble," a number that was changed to 63 cases later. Even the radioactivity sensors around the site encountered trouble, the reading from these devices are normally available online, giving the public a direct measure of ambient radioactivity around the site, but due to damage sustained during the earthquake, stopped reporting on the website. The company published an apology on that page, and data from the devices covering the off-line period was released later, showing no artificial abnormalities (note that the readings naturally fluctuate depending on whether it's raining or snowing and a host of other factors).


title: Kashiwazaki-Kariwa Nuclear Power Plant

text: TEPCO's president maintained that fears of a leak of radioactive material were unfounded (since the amount leaked into the ocean was a billionth of the legal limit), but many international reporters expressed distrust of the company that has a history of cover-up controversies. The IAEA's Mohamed ElBaradei encouraged full transparency throughout the investigation of the accident so that lessons learned could be applied to nuclear plants elsewhere.


title: Kashiwazaki-Kariwa Nuclear Power Plant

text: News of the earthquake, combined with the fact that replacement power sources (such as oil and gas) are at record highs, caused TEPCOs stock to plummet 7.5%, the largest drop in seven years, which amounted to around US$4.4 billion lost in stock capitalization. This made the event even more costly to the company than the 2002 data falsification scandal. Additionally, TEPCO warned that the plant closure could cause a power shortage during the summer months. Trade minister Akira Amari requested that business users cut electricity use, and in August TEPCO was forced to reduce electricity supplies for industrial uses, the first time it had to resort to such measures in 17 years.


title: Kashiwazaki-Kariwa Nuclear Power Plant

text: Reports of the leak caused thousands of cancellations at resorts and hotels along the Sea of Japan coast, even as far as Murakami, Niigata (140 km northeast) and Sado Island. Inn owners have said that rumors have been more damaging than direct effects of the earthquake.


title: Kashiwazaki-Kariwa Nuclear Power Plant

text: The shutdown forced TEPCO to run natural gas plants in place of this plant, not only increasing Japan's demand for the fuel and increasing the price internationally, but also increasing carbon dioxide output such that Japan will have difficulty meeting the Kyoto Protocol.


title: Kashiwazaki-Kariwa Nuclear Power Plant

text: After 16 months of comprehensive component-based assessment and upgrades on all seven reactors, this phase of post-earthquake response was almost complete, with Reactor 7 fully upgraded to cope with the seismic environment. On 8 November 2008, fuel loading in reactor Unit 7 started, preparatory to a period of system safety tests on that reactor. On 19 February 2009 TEPCO applied to the local governance to restart Unit 7 after having obtained approval from the national government and regulators. Local government agreement for restart was granted in May and electrical grid power was supplied from Unit 7 at 20% power on 19 May. The reactor was raised to 100% power on 5 June 2009 as part of a series of restart tests.


title: Kashiwazaki-Kariwa Nuclear Power Plant

text: Unit 1 restarted on 31 May 2010 after loading with fuel (along with Unit 5) earlier in the year, and was generating grid power by 6 June 2010.


title: Kashiwazaki-Kariwa Nuclear Power Plant

text: Unit 5 recommenced grid generation on 26 November 2010, in the same week that fuel loading for Unit 3 started.


title: Kashiwazaki-Kariwa Nuclear Power Plant

text: The reactors were shut down indefinitely following the 2011 Tōhoku earthquake and tsunami. Plans to restart units 6 and 7 were delayed after problems developed with the intruder detection system.


title: Kashiwazaki-Kariwa Nuclear Power Plant

text: On 21 April 2011, after the Fukushima Daiichi nuclear disaster, TEPCO announced a plan to build up the seawall to a height of 15 m (49.2 ft) above sea level and spanning more than 800 m (2,624 ft) in length for units 1–4, and more than 500 m (1,640 ft) for units 5–7 by June 2013. The height of a potential tsunami was assumed to be 3.3 m. Also, plans were made to rebuild the radioactive overflow storage pool to be completed by September 2012.


title: Kashiwazaki-Kariwa Nuclear Power Plant

text: On 10 November 2011, TEPCO announced a survey for signs of past tsunamis in this area. With drills, soil samples were to be taken of sediment layers dating from the year 1600 back to 7000 years ago, at nine locations around the plant at the coast of central Japan. This survey, the first that TEPCO ever conducted on this subject, did start on 15 November 2011, and was planned to be completed in April 2012, and was done to examine the possibility of higher tsunamis than had been expected at the time the plant was designed and built.


title: Kashiwazaki-Kariwa Nuclear Power Plant

text: On 26 April 2012, TEPCO said that it would recalculate the risks of earthquakes and tsunamis. This was done after reports, as published by four prefectures around the nuclear Plant, re-estimated the risks of potential earthquakes in the region:


title: Kashiwazaki-Kariwa Nuclear Power Plant

text: The calculated earthquake magnitudes are almost three times stronger than all the calculations done by TEPCO regarding the safety assessments for the plant. These were based on a magnitude 7.85 quake caused by a 131 kilometer long fault near Sado Island in Niigata and a 3.3 meter-high tsunami. To endure this, an embankment was under construction to resist tsunami waves up to 15 meters high. The recalculation could have consequences for the stress tests and safety assessments for the plant.


title: Kashiwazaki-Kariwa Nuclear Power Plant

text: After the planned revision of the safety standards in July 2013, some faults under the reactors were considered as geologically active. This was found by Japanese news agency Kyodo News on 23 January 2013 in papers and other material published by TEPCO. Under the new regulations, geologic faults would be considered to be active if they had moved within the last 400,000 years, instead of the less stringent standard of 120 000 years, as was formerly accepted.


title: Kashiwazaki-Kariwa Nuclear Power Plant

text: Two faults, named "Alpha" and "Beta," are present under Reactors 1 and 2. Other faults are situated under Reactor 3 and Reactor 5, as well as underneath the building of Reactor 4. Under the new regulations, the beta-fault could be classified as active because it moved a ground layer including volcanic ash around 240,000 years ago. The outcome of the study might trigger a second survey by the newly installed Japanese regulator NRA. In January 2013, studies were conducted or planned on geological faults around six Japanese reactor sites. The Kashiwazaki-Kariwa plant would be number seven.


title: Kashiwazaki-Kariwa Nuclear Power Plant

text: Kashiwazaki-Kariwa is one of the 44 nuclear power plants in Japan that have been rendered inactive in the years following the Fukushima Daiichi Accident. By October 2020, the Japanese government had inspected the plant, and by January 2020, TEPCO had completed its improvements on Unit 7. The company outlined plans to restart the reactor as early as the end of the Japanese 2022 Fiscal year (31 March 2022), however, the Nuclear Regulation Authority released a report in April 2021 indicating that there were serious security infractions and enacted an order that postponed the restart indefinitely.


title: Kashiwazaki-Kariwa Nuclear Power Plant

text: Following the April 2021 NRA report, TEPCO admitted that its intruder detection system was left broken in order to reduce costs and confirmed that an unauthorized personnel member used a colleague's ID card to access the plant's central control room in September 2020. In response, TEPCO plans to implement anti-terrorism measures, install an intrusion detection system, and hire an additional 30 guards to protect nuclear material at the facility. The power company intends to invest ¥20 Billion (US$165.4 Million) on these security measures from 31 March 2023 to 31 March 2028.


title: Kashiwazaki-Kariwa Nuclear Power Plant

text: According to a report from TEPCO, the NRA began Additional Inspection (Phase II) to monitor the new security measures at the plant. In April 2022, it was confirmed that the security flaws revealed in the NRA's April 2022 report were limited to Kashiwazaki-Kariwa and not indicative of a widespread issue throughout the company's culture. TEPCO is planning on moving nearly 40% of their nuclear division employees to Niigata Prefecture in preparation of its plans to restart Reactor 7 and begin rebuilding trust in the citizens, but the future of Kashiwazaki-Kariwa is still uncertain. As of 26 May 2022, the local government has yet to move forward with approval for TEPCO to set forth their plans to restart. According to a 2021 survey by "Niigata Nippo", just over half of Niigata prefecture residents oppose a nuclear restart.


title: SG-1000

text: The is a home video game console manufactured by Sega. It was Sega's first entry into the home video game hardware business. Developed in response to a downturn in arcades starting in 1982, the SG-1000 was created on the advice of Hayao Nakayama, president of Sega's Japanese arm, and was released on July 15, 1983, the same day that Nintendo released the Family Computer in Japan. It also saw limited release in Australia and New Zealand.


title: SG-1000

text: The SG-1000 was released in several forms, including the SC-3000 computer and the redesigned SG-1000 II released in 1984. The SG-1000 and the SC-3000 both support a library of 76 ROM cartridge games and 29 Sega My Card games.


title: SG-1000

text: A third iteration of the console, the Sega Mark III, was released in 1985. It provided an improved custom video display processor over previous iterations and served as the basis for the Master System in 1986, Sega's first internationally released console. All SG-1000 games are fully compatible with the Mark III and the Japanese version of the Master System.


title: SG-1000

text: In the early 1980s, Sega Enterprises, Inc., then a subsidiary of Gulf and Western, was one of the top five arcade game manufacturers active in the United States, as company revenues rose to $214 million. A downturn in the arcade business starting in 1982 seriously hurt the company, leading Gulf and Western to sell its North American arcade manufacturing organization and the licensing rights for its arcade games to Bally Manufacturing. The company retained Sega's North American R&D operation, as well as its Japanese subsidiary, Sega Enterprises, Ltd. With its arcade business in decline, Sega Enterprises, Ltd. president Hayao Nakayama advocated that the company leverage its hardware expertise to move into the home console market in Japan, which was in its infancy at the time. Nakayama received permission to proceed. The first model to be developed was the SC-3000, a computer with a built-in keyboard, but when Sega learned of Nintendo's plans to release a games-only console, they began developing the SG-1000 alongside the SC-3000. The "SG" in the console's name is an abbreviation for "Sega Game", and the console is also sometimes referred to as the "Mark I". To keep costs down while ensuring sufficient longevity, Sega opted to create the platform from popular off-the-shelf components.


title: SG-1000

text: The SG-1000 was first released in Japan on July 15, 1983, at ¥15,000. It was released on the same day as Nintendo launched the Family Computer (Famicom) in Japan. It was released simultaneously with the SC-3000, also known as the Sega Personal Computer SC-3000, as well as the upgraded SC-3000H. Though Sega themselves only released the SG-1000 in Japan, rebranded versions were released in several other markets worldwide. Released at nearly the same time as the Japanese version, the SG-1000 was released in Australia through John Sands Electronics and in New Zealand by Grandstand Leisure. The console also saw a release in Italy and Spain, but was not released in the larger video game markets of the United States, United Kingdom, or Germany. Despite this, an unauthorized clone system known as the Telegames Personal Arcade was produced and made available in the United States and Taiwan, and is able to play SG-1000 and ColecoVision games. An additional release of the SG-1000 in Taiwan was done by Aaronix. The console enjoyed a brief period of popularity in Taiwan before the market was taken over by cheaper Famicom clones.


title: SG-1000

text: Due in part to the SG-1000's steadier stream of releases (21 SG-1000 games by the end of 1983, as compared to only 9 Famicom games), and in part to a recall on Famicom units necessitated by a faulty circuit, the SG-1000 chalked up 160,000 units in sales in 1983, far exceeding Sega's projection of 50,000 units. Former Sega consumer hardware development head Hideki Sato stated that because Sega had not predicted the SG-1000 would sell so well, the company became more enamored with developing video game consoles. Despite this, the three launch games, all of which were ported from Sega's VIC dual-arcade board, lacked the name recognition of Famicom launch games "Donkey Kong", "Donkey Kong Jr.", and "Popeye". Shortly after launch, Gulf and Western began to divest itself of its non-core businesses after the death of company founder Charles Bluhdorn, so Nakayama and former Sega CEO David Rosen arranged a management buyout of the Japanese subsidiary in 1984 with financial backing from CSK Corporation, a prominent Japanese software company. Nakayama was then installed as CEO of the new Sega Enterprises, Ltd.


title: SG-1000

text: Following the buyout, Sega released another console, the SG-1000 II, on July 31, 1984 at ¥15,000. It is sometimes referred to as the "SG-1000 Mark II". The SG-1000 II replaced the hardwired joystick with two detachable joypads. Sato disliked the original cartridges, saying they looked like "small black tombstones" when inserted in the console, and later remarked that his proudest achievement of the SG-1000 era was replacing them with the "cheerier", pocket-sized Sega My Cards. Sega also employed popular owarai comedy duo Tunnels to provide celebrity endorsement for the console.


title: SG-1000

text: By 1984, the Famicom's success began to outpace the SG-1000. The Famicom had more advanced hardware, allowing it to perform smoother scrolling and more colorful sprites, and Nintendo boosted its games library by courting third-party developers, whereas Sega was less than eager to collaborate with the same companies they were competing with in arcades. The SG-1000 was also coming up against game consoles from companies including Tomy and Bandai. This would result in the release of the Sega Mark III in Japan in 1985, which later became the Master System worldwide. The last cartridge released was "Portrait of Loretta" on February 18, 1987. In 2006, the GameTap subscription gaming service added an emulator of the SG-1000, and several playable titles.


title: SG-1000

text: The SG-1000 is powered by an 8-bit Zilog Z80 central processing unit running at 3.58 MHz for the SG-1000 and SG-1000 II, and at 4 MHz for the SC-3000. Its video processor is a Texas Instruments TMS9918A, capable of displaying up to 16 colors, and its sound processor is a Texas Instruments SN76489. The system includes 8 kbit (1 KB) of RAM. The controller is hardwired to the system in the original model, and detachable in the SG-1000 II. Video and audio output are supplied through an RF switch. Power is supplied through a 9 V DC connector connected to an AC adapter.


title: SG-1000

text: Several peripherals exist for the SG-1000 series. Available at ¥13,800 at its time of release, the SK-1100 keyboard connects through the expansion slot and is compatible with all models. Multiple controllers were created, including the SJ-200 joystick attached to the SG-1000, and the SJ-150 joypad, made for use with the SG-1000 II. A racing wheel known as the SH-400 was made for use with games such as "Monaco GP". The C-1000 Card Catcher, sold at ¥1,000, allowing players to play Sega My Card titles. Additional accessories existed solely for use with the SC-3000, including the SR-1000 cassette deck, the SP-400 4-color plotter printer, and the SF-7000 expansion device which adds a floppy disk drive and additional memory.


title: SG-1000

text: Sega's software library for the SG-1000 and SC-3000 comprises 42 game cartridges and 29 Sega My Card releases that required the Card Catcher add-on. There were also 26 educational and programming cartridges for the SC-3000 that could only be played on the SG-1000 with the SK-1100 keyboard peripheral. Titles for the system include "Flicky", "Congo Bongo", "Sega-Galaga", and "Girl's Garden", the first video game programmed by "Sonic the Hedgehog" developer Yuji Naka. The library included licensed titles, such as "Golgo 13". Packaging and game manuals came with both Japanese and English text until 1984, when manuals were switched to Japanese only and the size of the cartridge box was reduced. Hideki Sato stated that Sega lacked adequate staff to develop games for the console at the time. SC-3000/SG-1000 games were continued to be produced after the launch of the Mark III in 1985. The last two SC-3000/SG-1000 cartridge games were "The Castle" in 1986 and "Portrait of Loretta" in 1987. The final Sega My Card game for the SC-3000/SG-1000 was "The Black Onyx", also in 1987.


title: SG-1000

text: The SG-1000 console series (including the Mark III) sold over units in Japan , with the original SG-1000 model having sold 400,000 units in Japan. The SC-3000 home computer model sold 120,000 units in Japan during 1983.


title: SG-1000

text: The SG-1000 made little impact on the video game industry, but has been recognized for being Sega's first video game console. "Retro Gamer" writer Damien McFerran said it was an "abject failure", but called it and the SG-1000 II "the Japanese forefathers of the Master System". Writing for "Wired", Chris Kohler criticized the poor response of the controller's joystick and the lack of an RCA output. He said the release timing hurt its success; "[al]though its graphics were of better quality than most consoles on the market, it had the bad luck to be released in the same month as Nintendo's world-changing Famicom, which had killer apps like "Donkey Kong" and could run circles around Sega's hardware." Of its legacy, Kohler said, "Few have heard of it, even fewer have played it, and the games weren't that great anyway." By contrast, Luke Plunkett of "Kotaku" recognized that "while all this makes it sound like the SG-1000 was a bit of a misfire, it was still important in the development of Sega's home console business."


title: SG-1000

text: Hideki Sato reflected positively on the innovations in the development of the SG-1000, but admitted that the console had limitations because of how new the market was and that Sega was inexperienced in developing for a video game console at the time. According to Sato, "The problem was, while we knew how to make arcade games, we didn’t really know anything about console development. In fact, the very idea of a “consumer” market for video games was unheard of then: back then it was just a 'new business' idea."


title: Kongō-class destroyer

text: The of guided-missile destroyers in the Japan Maritime Self-Defense Force are equipped with the Aegis Combat System, and is the first of few ship classes outside the United States to have that capability. Following a decision made in December 2003, Japan is upgrading their "Kongo"-class destroyers with Aegis Ballistic Missile Defense System. The upgrade involves a series of installations and flight tests to take place from 2007 to 2010. JS "Kongo" was the first ship to have the BMD upgrade installed.


title: Kongō-class destroyer

text: The JMSDF built under FY1960 program and started shipboard operation of surface-to-air missiles. She had been equipped with analog-version of the Tartar Guided Missile Fire Control System. A fully-digitized system was adopted on the next-generation , and later a combat direction system based on the Naval Tactical Data System was added.


title: Kongō-class destroyer

text: Nevertheless, the JMSDF estimated that its fleets would not survive against Soviet airstrikes, especially Tupolev Tu-22M bombers and AS-4 air-to-surface missiles. Based on these estimates, JMSDF began to pursue the introduction of the Aegis Weapon System (AWS) from the early 1980s. In 1984, with the prospect of deploying AWS, concrete implementation plans began. And the construction of Japanese first Aegis-equipped ships, "Kongo" class, had begun under the FY1988 program.


title: Kongō-class destroyer

text: The overall design is generally modeled on the s of the U.S. Navy. The hull adopted shelter deck design as with preceding Japanese destroyers, but it was widened to support the superstructure with four PESA antennas just as "Arleigh Burke" class. Due to this widened hull, the outer panel is inclined to reduce the width of the waterline, which also has the effect of reducing radar cross section area.


title: Kongō-class destroyer

text: Because they are built to different operational requirements than the "Arleigh Burke"-class destroyers, such as for carrying extra commanding equipment, the "Kongō"-class ships' internal arrangement is quite different from the original design on which they are based. Recognisable external features are the vertical mast and enlarged superstructure to carry sufficient headquarters equipment so that they could act as a flagship.


title: Kongō-class destroyer

text: The propulsion systems are almost the same as those of the "Arleigh Burke" class, powered by four Ishikawajima-Harima LM2500 gas turbines giving them a top speed of .


title: Kongō-class destroyer

text: The class is equipped with the Aegis Weapon System (AWS). The system version was Baseline 4 for name-ship through the third ship, and Baseline 5 for fourth ships immediately after they were put into service; then all ships were updated to Baseline 5.3 with modernization. The class uses the AN/SPY-1D as the main radar. As surface-to-air missiles, the SM-2MR Block IIIA was initially used, and later the Block IIIB came into use. Since the mid-2000s, they have also been equipped with a missile defense capability with the primary intention of countering North Korean ballistic missiles, and now have an Aegis BMD 3.6 system installed to launch SM-3 Block IA and IB missiles.


title: Kongō-class destroyer

text: The Mark 41 Vertical Launching System arrangement, similar to the "Arleigh Burke" class, consisted of 29 cells on the foredeck and 61 cells on the afterdeck. These cells contain not only RIM-162, SM-2, and SM-3, but also VL-ASROCs. In addition, they are equipped with HOS-302, one of the Japanese variant of the Mark 32 Surface Vessel Torpedo Tubes, as anti-submarine weapons and Harpoon as anti-ship missiles. And as gunnery weapons, an Oto Melara /54 caliber gun and two Mark 15 20 mm CIWS gun mounts are installed.


title: Kongō-class destroyer

text: Most of electronic devices outside of AWS originated in Japan. For electronic warfare, this class is equipped with NOLQ-2, an elaborate system capable of both ES and EA. The OQS-102 sonar is equivalent to the U.S. SQS-53C.


title: Kongō-class destroyer

text: In December 2007, Japan conducted a successful test of the SM-3 block IA against a ballistic missile aboard . This was the first time a Japanese ship was selected to launch the interceptor missile during a test of the Aegis Ballistic Missile Defense System. In previous tests, they provided tracking and communications. Afterward, Japan has also undertaken another two successful Ballistic Missile Defense tests aboard in October 2009 and aboard in October 2010. While one test aboard in November 2008 failed to intercept the target.


title: Kongō-class destroyer

text: The "Kongō"-class destroyers are named after mountains in Japan, and all four also share their names with World War II-era Japanese warships. "Kongō" and "Kirishima" share their names with two ships of the , while the other two ships share their names with the heavy cruisers and .


title: Zorn's lemma

text: Zorn's lemma, also known as the Kuratowski–Zorn lemma, is a proposition of set theory. It states that a partially ordered set containing upper bounds for every chain (that is, every totally ordered subset) necessarily contains at least one maximal element.


title: Zorn's lemma

text: The lemma was proved (assuming the axiom of choice) by Kazimierz Kuratowski in 1922 and independently by Max Zorn in 1935. It occurs in the proofs of several theorems of crucial importance, for instance the Hahn–Banach theorem in functional analysis, the theorem that every vector space has a basis, Tychonoff's theorem in topology stating that every product of compact spaces is compact, and the theorems in abstract algebra that in a ring with identity every proper ideal is contained in a maximal ideal and that every field has an algebraic closure.


title: Zorn's lemma

text: Zorn's lemma is equivalent to the well-ordering theorem and also to the axiom of choice, in the sense that within ZF (Zermelo–Fraenkel set theory without the axiom of choice) any one of the three is sufficient to prove the other two. An earlier formulation of Zorn's lemma is Hausdorff's maximum principle which states that every totally ordered subset of a given partially ordered set is contained in a maximal totally ordered subset of that partially ordered set.


title: Zorn's lemma

text: To prove the existence of a mathematical object that can be viewed as a maximal element in some partially ordered set in some way, one can try proving the existence of such an object by assuming there is no maximal element and using transfinite induction and the assumptions of the situation to get a contradiction. Zorn's lemma tidies up the conditions a situation needs to satisfy in order for such an argument to work and enables mathematicians to not have to repeat the transfinite induction argument by hand each time, but just check the conditions of Zorn's lemma.


title: Zorn's lemma

text: Variants of this formulation are sometimes used, such as requiring that the set "P" and the chains be non-empty.


title: Zorn's lemma

text: Although this formulation appears to be formally weaker (since it places on "P" the additional condition of being non-empty, but obtains the same conclusion about "P"), in fact the two formulations are equivalent. To verify this, suppose first that "P" satisfies the condition that every chain in "P" has an upper bound in "P". Then the empty subset of "P" is a chain, as it satisfies the definition vacuously; so the hypothesis implies that this subset must have an upper bound in "P", and this upper bound shows that "P" is in fact non-empty. Conversely, if "P" is assumed to be non-empty and satisfies the hypothesis that every non-empty chain has an upper bound in "P", then "P" also satisfies the condition that "every" chain has an upper bound, as an arbitrary element of "P" serves as an upper bound for the empty chain (that is, the empty subset viewed as a chain).


title: Zorn's lemma

text: The difference may seem subtle, but in many proofs that invoke Zorn's lemma one takes unions of some sort to produce an upper bound, and so the case of the empty chain may be overlooked; that is, the verification that all chains have upper bounds may have to deal with empty and non-empty chains separately. So many authors prefer to verify the non-emptiness of the set "P" rather than deal with the empty chain in the general argument.


title: Zorn's lemma

text: If "V" = {0}, then the empty set is a basis for "V". Now, suppose that "V" ≠ {0}. Let "P" be the set consisting of all linearly independent subsets of "V". Since "V" is not the zero vector space, there exists a nonzero element v of "V", so "P" contains the linearly independent subset {v}. Furthermore, "P" is partially ordered by set inclusion (see inclusion order). Finding a maximal linearly independent subset of "V" is the same as finding a maximal element in "P".


title: Zorn's lemma

text: To apply Zorn's lemma, take a chain "T" in "P" (that is, "T" is a subset of "P" that is totally ordered). If "T" is the empty set, then {v} is an upper bound for "T" in "P". Suppose then that "T" is non-empty. We need to show that "T" has an upper bound, that is, there exists a linearly independent subset "B" of "V" containing all the members of "T".


title: Zorn's lemma

text: Take "B" to be the union of all the sets in "T". We wish to show that "B" is an upper bound for "T" in "P". To do this, it suffices to show that "B" is a linearly independent subset of "V".


title: Zorn's lemma

text: Suppose otherwise, that "B" is not linearly independent. Then there exists vectors v, v, ..., v ∈ "B" and scalars "a", "a", ..., "a", not all zero, such that


title: Zorn's lemma

text: Since "B" is the union of all the sets in "T", there are some sets "S", "S", ..., "S" ∈ "T" such that v ∈ "S" for every "i" = 1, 2, ..., "k". As "T" is totally ordered, one of the sets "S", "S", ..., "S" must contain the others, so there is some set "S" that contains all of v, v, ..., v. This tells us there is a linearly dependent set of vectors in "S", contradicting that "S" is linearly independent (because it is a member of "P").


title: Zorn's lemma

text: The hypothesis of Zorn's lemma has been checked, and thus there is a maximal element in "P", in other words a maximal linearly independent subset "B" of "V".


title: Zorn's lemma

text: Finally, we show that "B" is indeed a basis of "V". It suffices to show that "B" is a spanning set of "V". Suppose for the sake of contradiction that "B" is not spanning. Then there exists some v ∈ "V" not covered by the span of "B". This says that "B" ∪ {v} is a linearly independent subset of "V" that is larger than "B", contradicting the maximality of "B". Therefore, "B" is a spanning set of "V", and thus, a basis of "V".


title: Zorn's lemma

text: Let "P" be the set consisting of all "proper" ideals in "R" (that is, all ideals in "R" except "R" itself). Since "R" is non-trivial, the set "P" contains the trivial ideal {0}. Furthermore, "P" is partially ordered by set inclusion. Finding a maximal ideal in "R" is the same as finding a maximal element in "P".


title: Zorn's lemma

text: To apply Zorn's lemma, take a chain "T" in "P". If "T" is empty, then the trivial ideal {0} is an upper bound for "T" in "P". Assume then that "T" is non-empty. It is necessary to show that "T" has an upper bound, that is, there exists an ideal "I" ⊆ "R" containing all the members of "T" but still smaller than "R" (otherwise it would not be a proper ideal, so it is not in "P").


title: Zorn's lemma

text: Take "I" to be the union of all the ideals in "T". We wish to show that "I" is an upper bound for "T" in "P". We will first show that "I" is an ideal of "R". For "I" to be an ideal, it must satisfy three conditions:


title: Zorn's lemma

text: Because "T" contains at least one element, and that element contains at least 0, the union "I" contains at least 0 and is not empty. Every element of "T" is a subset of "R", so the union "I" only consists of elements in "R".


title: Zorn's lemma

text: Suppose "x" and "y" are elements of "I". Then there exist two ideals "J", "K" ∈ "T" such that "x" is an element of "J" and "y" is an element of "K". Since "T" is totally ordered, we know that "J" ⊆ "K" or "K" ⊆ "J". Without loss of generality, assume the first case. Both "x" and "y" are members of the ideal "K", therefore their sum "x" + "y" is a member of "K", which shows that "x" + "y" is a member of "I".


title: Zorn's lemma

text: Suppose "x" is an element of "I". Then there exists an ideal "J" ∈ "T" such that "x" is in "J". If "r" ∈ "R", then "rx" is an element of "J" and hence an element of "I". Thus, "I" is an ideal in "R".


title: Zorn's lemma

text: Now, we show that "I" is a "proper" ideal. An ideal is equal to "R" if and only if it contains 1. (It is clear that if it is "R" then it contains 1; on the other hand, if it contains 1 and "r" is an arbitrary element of "R", then "r"1 = "r" is an element of the ideal, and so the ideal is equal to "R".) So, if "I" were equal to "R", then it would contain 1, and that means one of the members of "T" would contain 1 and would thus be equal to "R" – but "R" is explicitly excluded from "P".


title: Zorn's lemma

text: The hypothesis of Zorn's lemma has been checked, and thus there is a maximal element in "P", in other words a maximal ideal in "R".


title: Zorn's lemma

text: A sketch of the proof of Zorn's lemma follows, assuming the axiom of choice. Suppose the lemma is false. Then there exists a partially ordered set, or poset, "P" such that every totally ordered subset has an upper bound, and that for every element in "P" there is another element bigger than it. For every totally ordered subset "T" we may then define a bigger element "b"("T"), because "T" has an upper bound, and that upper bound has a bigger element. To actually define the function "b", we need to employ the axiom of choice.


title: Zorn's lemma

text: Using the function "b", we are going to define elements "a" < "a" < "a" < "a" < ... < a < a <…, in "P". This uncountably infinite sequence is really long: the indices are not just the natural numbers, but all ordinals. In fact, the sequence is too long for the set "P"; there are too many ordinals (a proper class), more than there are elements in any set, and the set "P" will be exhausted before long and then we will run into the desired contradiction.


title: Zorn's lemma

text: The "a" are defined by transfinite recursion: we pick "a" in "P" arbitrary (this is possible, since "P" contains an upper bound for the empty set and is thus not empty) and for any other ordinal "w" we set "a" = "b"({"a" : "v" < "w"}). Because the "a" are totally ordered, this is a well-founded definition.


title: Zorn's lemma

text: Kazimierz Kuratowski proved in 1922 a version of the lemma close to its modern formulation (it applies to sets ordered by inclusion and closed under unions of well-ordered chains). Essentially the same formulation (weakened by using arbitrary chains, not just well-ordered) was independently given by Max Zorn in 1935, who proposed it as a new axiom of set theory replacing the well-ordering theorem, exhibited some of its applications in algebra, and promised to show its equivalence with the axiom of choice in another paper, which never appeared.


title: Zorn's lemma

text: The name "Zorn's lemma" appears to be due to John Tukey, who used it in his book "Convergence and Uniformity in Topology" in 1940. Bourbaki's "Théorie des Ensembles" of 1939 refers to a similar maximal principle as "le théorème de Zorn". The name "" prevails in Poland and Russia.


title: Zorn's lemma

text: A well-known joke alluding to this equivalency (which may defy human intuition) is attributed to Jerry Bona:


title: Zorn's lemma

text: "The Axiom of Choice is obviously true, the well-ordering principle obviously false, and who can tell about Zorn's lemma?"


title: Zorn's lemma

text: Moreover, Zorn's lemma (or one of its equivalent forms) implies some major results in other mathematical areas. For example,


title: Zorn's lemma

text: In this sense, we see how Zorn's lemma can be seen as a powerful tool, applicable to many areas of mathematics.


title: Zorn's lemma

text: A weakened form of Zorn's lemma can be proven from ZF + DC (Zermelo–Fraenkel set theory with the axiom of choice replaced by the axiom of dependent choice). Zorn's lemma can be expressed straightforwardly by observing that the set having no maximal element would be equivalent to stating that the set's ordering relation would be entire, which would allow us to apply the axiom of dependent choice to construct a countable chain. As a result, any partially ordered set with exclusively finite chains must have a maximal element.


title: Zorn's lemma

text: More generally, strengthening the axiom of dependent choice to higher ordinals allows us to generalize the statement in the previous paragraph to higher cardinalities. In the limit where we allow arbitrarily large ordinals, we recover the proof of the full Zorn's lemma using the axiom of choice in the preceding section.


title: Generative model

text: In statistical classification, two main approaches are called the generative approach and the discriminative approach. These compute classifiers by different approaches, differing in the degree of statistical modelling. Terminology is inconsistent, but three major types can be distinguished, following :


title: Generative model

text: The distinction between these last two classes is not consistently made; refers to these three classes as "generative learning", "conditional learning", and "discriminative learning", but only distinguish two classes, calling them generative classifiers (joint distribution) and discriminative classifiers (conditional distribution or no distribution), not distinguishing between the latter two classes. Analogously, a classifier based on a generative model is a generative classifier, while a classifier based on a discriminative model is a discriminative classifier, though this term also refers to classifiers that are not based on a model.


title: Generative model

text: In application to classification, one wishes to go from an observation "x" to a label "y" (or probability distribution on labels). One can compute this directly, without using a probability distribution ("distribution-free classifier"); one can estimate the probability of a label given an observation, formula_3 ("discriminative model"), and base classification on that; or one can estimate the joint distribution formula_1 ("generative model"), from that compute the conditional probability formula_3, and then base classification on that. These are increasingly indirect, but increasingly probabilistic, allowing more domain knowledge and probability theory to be applied. In practice different approaches are used, depending on the particular problem, and hybrids can combine strengths of multiple approaches.


title: Generative model

text: Regardless of precise definition, the terminology is constitutional because a generative model can be used to "generate" random instances (outcomes), either of an observation and target formula_8, or of an observation "x" given a target value "y", while a discriminative model or discriminative classifier (without a model) can be used to "discriminate" the value of the target variable "Y", given an observation "x". The difference between "discriminate" (distinguish) and "classify" is subtle, and these are not consistently distinguished. (The term "discriminative classifier" becomes a pleonasm when "discrimination" is equivalent to "classification".)


title: Generative model

text: The term "generative model" is also used to describe models that generate instances of output variables in a way that has no clear relationship to probability distributions over potential samples of input variables. Generative adversarial networks are examples of this class of generative models, and are judged primarily by the similarity of particular outputs to potential inputs. Such models are not classifiers.


title: Generative model

text: In application to classification, the observable "X" is frequently a continuous variable, the target "Y" is generally a discrete variable consisting of a finite set of labels, and the conditional probability formula_9 can also be interpreted as a (non-deterministic) target function formula_10, considering "X" as inputs and "Y" as outputs.


title: Generative model

text: Given a finite set of labels, the two definitions of "generative model" are closely related. A model of the conditional distribution formula_6 is a model of the distribution of each label, and a model of the joint distribution is equivalent to a model of the distribution of label values formula_12, together with the distribution of observations given a label, formula_13; symbolically, formula_14 Thus, while a model of the joint probability distribution is more informative than a model of the distribution of label (but without their relative frequencies), it is a relatively small step, hence these are not always distinguished.


title: Generative model

text: Given a model of the joint distribution, formula_1, the distribution of the individual variables can be computed as the marginal distributions formula_16 and formula_17 (considering "X" as continuous, hence integrating over it, and "Y" as discrete, hence summing over it), and either conditional distribution can be computed from the definition of conditional probability: formula_18 and formula_19.


title: Generative model

text: Given a model of one conditional probability, and estimated probability distributions for the variables "X" and "Y", denoted formula_20 and formula_12, one can estimate the opposite conditional probability using Bayes' rule:


title: Generative model

text: Note that Bayes' rule (computing one conditional probability in terms of the other) and the definition of conditional probability (computing conditional probability in terms of the joint distribution) are frequently conflated as well.


title: Generative model

text: A generative algorithm models how the data was generated in order to categorize a signal. It asks the question: based on my generation assumptions, which category is most likely to generate this signal? A discriminative algorithm does not care about how the data was generated, it simply categorizes a given signal. So, discriminative algorithms try to learn formula_27 directly from the data and then try to classify data. On the other hand, generative algorithms try to learn formula_28 which can be transformed into formula_27 later to classify the data. One of the advantages of generative algorithms is that you can use formula_28 to generate new data similar to existing data. On the other hand, it has been proved that some discriminative algorithms give better performance than some generative algorithms in classification tasks.


title: Generative model

text: Despite the fact that discriminative models do not need to model the distribution of the observed variables, they cannot generally express complex relationships between the observed and target variables. But in general, they don't necessarily perform better than generative models at classification and regression tasks. The two classes are seen as complementary or as different views of the same procedure.


title: Generative model

text: With the rise of deep learning, a new family of methods, called deep generative models (DGMs), is formed through the combination of generative models and deep neural networks. An increase in the scale of the neural networks is typically accompanied by an increase in the scale of the training data, both of which are required for good performance.


title: Generative model

text: Popular DGMs include variational autoencoders (VAEs), generative adversarial networks (GANs), and auto-regressive models. Recently, there has been a trend to build very large deep generative models. For example, GPT-3, and its precursor GPT-2, are auto-regressive neural language models that contain billions of parameters, BigGAN and VQ-VAE which are used for image generation that can have hundreds of millions of parameters, and Jukebox is a very large generative model for musical audio that contains billions of parameters.


title: Generative model

text: If the observed data are truly sampled from the generative model, then fitting the parameters of the generative model to maximize the data likelihood is a common method. However, since most statistical models are only approximations to the "true" distribution, if the model's application is to infer about a subset of variables conditional on known values of others, then it can be argued that the approximation makes more assumptions than are necessary to solve the problem at hand. In such cases, it can be more accurate to model the conditional density functions directly using a discriminative model (see below), although application-specific details will ultimately dictate which approach is most suitable in any particular case.


title: Generative model

text: Suppose the input data is formula_31, the set of labels for formula_32 is formula_33, and there are the following 4 data points:


title: Generative model

text: For the above data, estimating the joint probability distribution formula_28 from the empirical measure will be the following:


title: Generative model

text: gives an example in which a table of frequencies of English word pairs is used to generate a sentence beginning with "representing and speedily is an good"; which is not proper English but which will increasingly approximate it as the table is moved from word pairs to word triplets etc.


title: Spartan Race

text: Spartan Race is a series of obstacle races of varying distance and difficulty ranging from 3 miles to marathon distances. These races are held in the United States and have been franchised to 30 countries, including Canada, South Korea, Australia, the Philippines and several European countries. The series include the Spartan Sprint, the Spartan Super, the Spartan Beast, and the Spartan Ultra. Spartan Race also has a military series, hosted on military bases. Spartan also holds winter and team events.


title: Spartan Race

text: Spartan Race began as a spin-off of the "Death Race", a 48-hour endurance event founded in 2007. Spartan was founded by De Sena, intended for it to be a more manageable endurance race for a wider audience. The first Spartan Race event was held in 2010 at the Catamount Outdoor Center in Williston, Vermont and represented the city of Burlington, Vermont. Roughly 500 competitors had to "run, crawl, jump and swim" and overcome a variety of obstacles. All finishers received a medal, and prizes were awarded to the top athletes.


title: Spartan Race

text: In 2012 Raptor Consumer Partners invested in the Spartan Race company. In 2013 Reebok had become the event title sponsor, and the races were renamed the "Reebok Spartan Race Series". On December 7, 2013, Universal Sports broadcast a special on the 2013 Spartan Race World Championships. In August 2015, parent network NBC then approved a Spartan-based television series, "", led by the producers of fellow NBC series "American Ninja Warrior". Later in 2015, Spartan Race founded the "Spartan Agoge" which is described as a "60 hour physical, tactical, mental and team based training and testing" event, to be held in Vermont twice a year. ESPN describes the Spartan Race as "a true test of will."


title: Spartan Race

text: Spartan Race acquired Tough Mudder, which had been forced into involuntary bankruptcy proceedings, in February 2020. It purchased Tough Mudder assets for $700,000 and the assumption of debts, including honoring prepaid tickets, which was approved by the bankruptcy court for the District of Delaware. Tough Mudder is expected to continue its races, and the 2020 season starts on April 17 in North London.


title: Spartan Race

text: Spartan Race's main events include the Spartan Sprint (3+ miles of obstacle racing, 20+ obstacles), the Spartan Super (8+ miles, 25+ obstacles), the Spartan Beast (13+ miles, 30+ obstacles), and the Spartan Ultra (30+ miles, 60+ obstacles). The obstacles themselves also vary from race to race. Frequently presented obstacles can include a fire jump, climbing under barbed wire, wall climbing, mud crawling, the "over-under-through" (a series of obstacles in which runners must first climb over a wall, then under a wall, then through a square hole placed in a wall), spear throw, rope climb, heavy object carries, "Herculean Hoist", "Tyrolean traverse", monkey bars, Traversal Wall (similar to a bouldering wall), Hobie Hop (a thick rubber band is placed around the ankles and participants hop through consecutive tires), Slip Wall (a wall built at an incline, roughly covered in grease), a zig-zag log jump, steep mud climbs (rolling mud), tractor pulls, underwater submerging below walls (dunk walls), Atlas carries, tire flips, stump balances (skipping on stumps across a pond), rope swing, and the now discontinued Gladiator Arena.


title: Spartan Race

text: Failure to fully complete any obstacles results in a 30 Burpee penalty (or in some cases, a penalty loop) that runners complete before continuing their race. A participant can obtain a Trifecta medal after completing a Spartan Sprint (or Spartan Stadion), a Spartan Super, and a Spartan Beast in one calendar year. As of the 2016 season, the finisher medal includes both the traditional circular medal and a wedge – one-third of a larger Trifecta medal. Each Spartan event also provides races for children ages 4 to 13: half-mile races for ages 4–8, and one mile races for those older than 8.


title: Spartan Race

text: The Spartan World Championships are held yearly, and to qualify for the event, men and women must finish top 5 in a U.S. Championship Series event or a Regional Championship in their respective category.


title: Spartan Race

text: The first Spartan Gym was opened in 2016, in the 1 Hotel in Miami. Additionally, Spartan Strong is a group fitness class offered exclusively at Life Time Fitness.


title: Spartan Race

text: The Sprint combines relatively easy trail running with 20 obstacles, held on off-road terrain featuring water and mud along a 5-kilometer course, and is considered a short-distance race.


title: Spartan Race

text: The Spartan Sprint is the first part of the Spartan Trifecta achievement, where participants are encouraged to complete 3 races, earning them The Ultimate Spartan Achievement.


title: Spartan Race

text: The Spartan Super has 25 to 30 obstacles along 8 to 10 miles of rugged terrain, and is considered a middle-distance race.


title: Spartan Race

text: The Spartan Beast is known to be the most difficult Spartan Race in terms of completing the trifecta; some participants can't finish and are marked as DNF.


title: Spartan Race

text: The Spartan Kids Race was created for boys and girls ages four to 13 to encourage exercising. The Kids Race is segmented into 3 different age groups:


title: Spartan Race

text: Spartan Trail is classic trail running the way it's meant to be. Get off the pavement and explore America's wilderness over 10k and Half Marathon distances.


title: Spartan Race

text: The Honor Series made its debut in 2016. The races occur on military bases throughout the country and are open to current military, veterans, and the general public. The course runs from 4–5 miles and contains obstacles similar to the other races.


title: Spartan Race

text: Monkey bars and burpees take the field during the Stadium Series, where Spartan turns America's ballparks into race courses. These events are typically three-mile Sprint-style races with more than 15 obstacles, and are held at baseball and football stadiums across the United States.


title: Spartan Race

text: The series provides competitors with access to stadiums with opportunities to step onto the field where the pros play, including the Dodgers, Cowboys, Packers, Red Sox, Phillies, Mets, Nationals and the San Francisco Giants. At Fenway Park, racers had to complete burpees in the Red Sox locker room.


title: Spartan Race

text: The name Stadion (running race) (or stade, Ancient Greek: στάδιον) is drawn from an ancient running event, part of the Ancient Olympic Games and the other Panhellenic Games.


title: Spartan Race

text: The annual Spartan Global Championship Series unfolds across more than 40 countries on the road to the Spartan World Championship. The series sees competitors facing off on the course, battling signature Spartan obstacles on varying terrains and natural conditions.


title: Spartan Race

text: Format: 14 National Series around the world lead into stand-alone championship events in five regions paving the road to the Spartan World Championship. Elite and Age Group competitors must qualify for Regional Championships and the World Championship.


title: Spartan Race

text: A hybrid of race and endurance events, the Ultra covers 30+ miles of terrain and features close to 70 obstacles. The Ultra is the only Spartan event featuring strict time cutoffs that must be met; competitors are warned that not all who sign up will finish.


title: Spartan Race

text: Competitors are encouraged to bring ‘Transition Containers’ to supply the participant with food and water at the halfway point of the race due to the general tenacity of the course.


title: Spartan Race

text: The Hurricane Heat Endurance Event was created in August 2011 due to the cancellation of a prior Spartan Race caused by Hurricane Irene. In the Hurricane Heat, the goal is for the competitors’ teams to reach the finish line; individual times are not applicable. The Hurricane Heat is composed of 4–8, 12, and 24 hour courses. Each Hurricane Heat event is unique to the others in terms of obstacles and location.


title: Spartan Race

text: Spartan Race brings a fully immersive training program that balances class time with hands-on practical application of those skills and lessons. The Spartan Agoge is held on The Farm in Pittsfield, Vermont, twice a year in the summer and winter—and in historic locations across the globe including Iceland, Mongolia, Isle of Skye in Scotland, and along the Great Wall of China.


title: Spartan Race

text: “Spartan on NBC Sports” is a five-race U.S. Championship series that airs on NBC Sports Network and regional Comcast SportsNetwork stations while the World Championship is broadcast on NBC. The 2017 Spartan World Championship was December 24, 2017.


title: Spartan Race

text: In 2016, Spartan launched an editorial website, Spartan Life, which features fitness, nutrition, and lifestyle content.


title: Spartan Race

text: In 2018, Spartan launched a series: "“Spartan: The Championship Series,“" on ESPN and ESPN 2, which is a five-episode series, and features all the action from Spartan's championship events.


title: Michael Vlamis

text: Michael Vlamis (born March 27, 1990) is an American actor, screenwriter, director, and producer known for his role as Michael Guerin in "Roswell, New Mexico". Vlamis made his feature directorial debut with his psychological thriller, "Crossword".


title: Michael Vlamis

text: Vlamis was born on March 27, 1990, in Chicago, Illinois. He is of Greek, Serbian and Lebanese ancestry. Vlamis moved to California to attend Chapman University, where he earned a Bachelor of Science degree in entrepreneurship.


title: Michael Vlamis

text: Vlamis began his career in marketing for Modify Watches. He made his television debut in an episode of "New Girl" and began acting in short films. He appeared in "MemE! True Hollywood Story", a short film he wrote that won the 2017 Snapchat Shorts contest, a competition for short films under 120 seconds in length. After quitting the marketing world in 2017 to drive for Uber and focus on writing, Vlamis booked the lead role of Michael Guerin in the CW's "Roswell, New Mexico". In 2019, Vlamis co-wrote a biopic about the life of late rapper Mac Miller, titled "Blue Side Park." The screenplay was later added to the 2019 Black List, a survey of "most-liked" unproduced film scripts. Vlamis appeared alongside Chloe Bennet in the 2020 film, "5 Years Apart", which was his first produced feature film. In 2022, he made his feature directorial debut with "Crossword", a psychological thriller he also wrote, produced, and acted in. Kenan Thompson's company, Artists For Artists, acquired the film to handle sales.


title: Red imported fire ant

text: The red imported fire ant (Solenopsis invicta), also known as the fire ant or RIFA, is a species of ant native to South America. A member of the genus "Solenopsis" in the subfamily Myrmicinae, it was described by Swiss entomologist Felix Santschi as a variant of "S. saevissima" in 1916. Its current specific name "invicta" was given to the ant in 1972 as a separate species. However, the variant and species were the same ant, and the name was preserved due to its wide use. Though South American in origin, the red imported fire ant has been accidentally introduced in Australia, New Zealand, several Asian and Caribbean countries, and the United States. The red imported fire ant is polymorphic, as workers appear in different shapes and sizes. The ant's colours are red and somewhat yellowish with a brown or black gaster, but males are completely black. Red imported fire ants are dominant in altered areas and live in a wide variety of habitats. They can be found in rain forests, disturbed areas, deserts, grasslands, alongside roads and buildings, and in electrical equipment. Colonies form large mounds constructed from soil with no visible entrances because foraging tunnels are built and workers emerge far away from the nest.


title: Red imported fire ant

text: These ants exhibit a wide variety of behaviours, such as building rafts when they sense that water levels are rising. They also show necrophoric behaviour, where nestmates discard scraps or dead ants on refuse piles outside the nest. Foraging takes place on warm or hot days, although they may remain outside at night. Workers communicate by a series of semiochemicals and pheromones, which are used for recruitment, foraging, and defence. They are omnivores and eat dead mammals, arthropods, insects, seeds, and sweet substances such as honeydew from hemipteran insects with which they have developed relationships. Predators include arachnids, birds, and many insects including other ants, dragonflies, earwigs, and beetles. The ant is a host to parasites and to a number of pathogens, nematodes, and viruses, which have been viewed as potential biological control agents. Nuptial flight occurs during the warm seasons, and the alates may mate for as long as 30 minutes. Colony founding can be done by a single queen or a group of queens, which later contest for dominance once the first workers emerge. Workers can live for several months, while queens can live for years; colony numbers can vary from 100,000 to 250,000 individuals. Two forms of society in the red imported fire ant exist: polygynous colonies (nests with multiple queens) and monogynous colonies (nests with one queen).


title: Red imported fire ant

text: Venom plays an important role in the ant's life, as it is used to capture prey or for defence. About 95% of the venom consists of water-insoluble piperidine alkaloids known as solenopsins, with the rest comprising a mixture of toxic proteins that can be particularly potent in sensitive humans. More than 14 million people are stung by them in the United States annually, where many are expected to develop allergies to the venom. Most victims experience intense burning and swelling, followed by the formation of sterile pustules, which may remain for several days. However 0.6% to 6.0% of people may suffer from anaphylaxis, which can be fatal if left untreated. Common symptoms include dizziness, chest pain, nausea, severe sweating, low blood pressure, loss of breath, and slurred speech. More than 80 deaths have been recorded from red imported fire ant attacks. Treatment depends on the symptoms; those who only experience pain and pustule formation require no medical attention, but those who suffer from anaphylaxis are given epinephrines. Whole body extract immunotherapy is used to treat victims and is regarded as highly effective.


title: Red imported fire ant

text: The ant is viewed as a notorious pest, causing billions of dollars in damage annually and impacting wildlife. The ants thrive in urban areas, so their presence may deter outdoor activities. Nests can be built under structures such as pavements and foundations, which may cause structural problems, or cause them to collapse. Not only can they damage or destroy structures, but red imported fire ants also can damage equipment and infrastructure and impact business, land, and property values. In agriculture, they can damage crops and machinery, and threaten pastures. They are known to invade a wide variety of crops, and mounds built on farmland may prevent harvesting. They also pose a threat to animals and livestock, capable of inflicting serious injury or killing them, especially young, weak, or sick animals. Despite this, they may be beneficial because they consume common pest insects on crops. Common methods of controlling these ants include baiting and fumigation; other methods may be ineffective or dangerous. Due to its notoriety and importance, the ant has become one of the most studied insects on the planet, even rivalling the western honey bee ("Apis mellifera").


title: Red imported fire ant

text: The specific epithet of the red imported fire ant, "invicta", derives from Latin, and means "invincible" or "unconquered". The epithet originates from the phrase "Roma invicta" ("unconquered Rome"), used as an inspirational quote until the fall of the Western Roman Empire in 476 AD. The generic name, "Solenopsis", translates as "appearance" or "face" from Ancient Greek. It is a compound of two Ancient Greek words–"solen", meaning "pipe" or "channel", and "opsis", meaning "appearance" or "sight". The ant is commonly known as the "red imported fire ant" (abbreviated as RIFA). The "fire ant" part is because of the burning sensation caused by its sting. Alternative names include: the "fire ant", "red ant" or "tramp ant". In Brazil, locals call the ant "toicinhera", which derives from the Portuguese word "toicinho" (pork fat).


title: Red imported fire ant

text: The red imported fire ant was first described by Swiss entomologist Felix Santschi in a 1916 journal article published by "Physis". Originally named "Solenopsis saevissima wagneri" from a syntype worker collected from Santiago del Estero, Argentina, Santschi believed the ant was a variant of "S. saevissima"; the specific epithet, "wagneri", derives from the surname of E.R. Wagner, who collected the first specimens. The type material is currently housed in Naturhistorisches Museum Basel, Switzerland, but additional type workers are possibly housed in the Muséum national d'histoire naturelle, Paris. In 1930, American myrmecologist William Creighton reviewed the genus "Solenopsis" and reclassified the taxon as "Solenopsis saevissima electra wagneri" at infrasubspecific rank, noting that he could not collect any workers that referred to Santschi's original description. In 1952, the "S. saevissima" species complex was examined and, together with nine other species-group names, "S. saevissima electra wagneri" was synonymised with "S. saevissima saevissima". This reclassification was accepted by Australian entomologist George Ettershank in his revision of the genus and in Walter Kempf's 1972 catalogue of Neotropical ants.


title: Red imported fire ant

text: In 1972, American entomologist William Buren described what he thought was a new species, naming it "Solenopsis invicta". Buren collected a holotype worker from Cuiabá in Mato Grosso, Brazil, and provided the first official description of the ant in a journal article published by the Georgia Entomological Society. He accidentally misspelled "invicta" as above the description pages of the species, although it was clear that "invicta" was the intended spelling because of the constant use of the name in the article. The type material is currently housed in the National Museum of Natural History, Washington, D.C.


title: Red imported fire ant

text: In a 1991 review of the species complex, American entomologist James Trager synonymised "S. saevissima electra wagneri" and "S. wagneri" together. Trager incorrectly cites "Solenopsis saevissima electra wagneri" as the original name, erroneously believing that the name "S. wagneri" was unavailable and used Buren's name "S. invicta". Trager previously believed that "S. invicta" was conspecific with "S. saevissima" until comparing the material with "S. wagneri". Trager notes that though "S. wagneri" has priority over "S. invicta", the name was never used above infrasubspecific rank. The use of the name since Santschi has not been associated with collected specimens, and as a result is "nomen nudum". In 1995, English myrmecologist Barry Bolton corrected Trager's error, recognising "S. wagneri" as the valid name and synonymised "S. invicta". He states that Trager wrongfully classified "S. wagneri" as an unavailable name and cites "S. saevissima electra wagneri" as the original taxon. He concludes that "S. wagneri" is, in fact, the original name and has priority over "S. invicta".


title: Red imported fire ant

text: In 1999, Steve Shattuck and colleagues proposed conserving the name "S. invicta". Since the first description of "S. invicta", over 1,800 scientific papers using the name were published discussing a wide range of topics about its ecological behaviour, genetics, chemical communication, economic impacts, methods of control, population, and physiology. They state that the use of "S. wagneri" is a "threat" to nomenclatural stability towards scientists and non-scientists; taxonomists may have been able to adapt to such name change, but name confusion may arise if such case occurred. Due to this, Shattuck and his colleagues proposed the continued use of "S. invicta" and not "S. wagneri", as this name has been rarely used; between 1995 and 1998, over 100 papers were published using "S. invicta" and only three using "S. wagneri". They requested that the International Commission on Zoological Nomenclature (ICZN) use plenary powers to suppress "S. wagneri" for the purpose of the Principle of Priority and not for the Principle of Homonymy. Furthermore, they requested that the name "S. invicta" be added to the Official List of Specific Names in Zoology and that "S. wagneri" be added to the Official Index of Rejected Invalid Specific Names in Zoology. Upon review, the proposal was voted on by the entomological community and was supported by all but one voter. They note that there is no justification in suppressing "S. wagneri"; instead, it would be better to give precedence to "S. invicta" over "S. wagneri" whenever an author treated them as conspecific. The ICZN would conserve "S. invicta" and suppress "S. wagneri" in a 2001 review. Under the present classification, the red imported fire ant is a member of the genus "Solenopsis" in the tribe Solenopsidini, subfamily Myrmicinae. It is a member of the family Formicidae, belonging to the order Hymenoptera, an order of insects containing ants, bees, and wasps.


title: Red imported fire ant

text: The red imported fire ant is a member of the "S. saevissima" species-group. Members can be distinguished by their two-jointed clubs at the end of the funiculus in workers and queens, and the second and third segments of the funiculus are twice as long and broad in larger workers. Polymorphism occurs in all species and the mandibles bear four teeth. The following cladogram shows the position of the red imported fire ant among other members of the "S. saevissima" species-group:


title: Red imported fire ant

text: Phenotypic and genetic data suggest that the red imported fire ant and the black imported fire ant ("Solenopsis richteri") differ from each other, but they do share a close genetic relationship. Hybridisation between the two ants occurs in areas where they make contact, with the hybrid zone located in Mississippi. Such hybridisation has resulted from secondary contact between these two ants several decades ago, when they first encountered each other in southern Alabama. Based on mitochondrial DNA, examined haplotypes do not form a monophyletic clade. Some of the examined haplotypes form a closer relationship to "S. megergates", "S. quinquecuspis" and "S. richteri" than they do with other "S. invicta" haplotypes. The occurrence of a possible paraphyletic grouping suggests that the red imported fire ant and "S. quinquecuspis" are possible cryptic species groups composed of several species that cannot be distinguished morphologically.


title: Red imported fire ant

text: Studies show that mitochondrial DNA variation occurs substantially in polygyne societies (nests with multiple queens), but no variation is detected in monogyne societies (nests with a single queen). Triploidy (a chromosomal abnormality) occurs in red imported fire ants at high rates (as high as 12% in non-reproductive females), which is linked to the high frequency of diploid males. The red imported fire ant is the first species shown to possess a green-beard gene, by which natural selection can favour altruistic behaviour. Workers containing this gene are able to distinguish between queens containing it, and those that do not, apparently by using odour cues. The workers kill queens that do not contain the gene. In 2011, scientists announced they had fully sequenced the red imported fire ant genome from a male.


title: Red imported fire ant

text: Red imported fire ant workers range in size from small to medium, making them polymorphic. Workers measure between . The head measures and is wide. In the larger workers (as in the major workers), their heads measure and wide. The antenna scapes measure and the thoracic length is . The head becomes wider behind the eyes with rounded occipital lobes present, and unlike the similar-looking "S. richteri", the lobes peak further than the midline, but the occipital excision is not as crease-like. The scapes in major workers do not extend beyond occipital peak by one or two scape diameters; this feature is more noticeable in "S. richteri". In medium-sized workers, the scapes reach the occipital peaks and exceed the rear border in the smallest workers. In small and medium workers, the head tends to have more elliptical sides. The head of small workers is wider out front than it is behind. In the major workers, the pronotum does not have any angular shoulders, nor does it have any sunken posteromedian area. The promesonotum is convex and the propodeum base is rounded and also convex. The base and declivity are of equal length. The suture of the promesonotum is either strong or weak in larger workers. The petiole has a thick and blunt scale; if observed from behind, it is not as rounded above in contrast to "S. richteri", and sometimes it may be subtruncate. The postpetiole is large and broad, and in the larger workers, it is broader than its length. The postpetiole tends to be less broad in front and broader behind. On the rear side of the dorsal surface, a transverse impression is present. In "S. richteri", this feature is also present but much weaker.


title: Red imported fire ant

text: The sculpture is very similar to "S. richteri". The punctures are from where pilosity arises, and these are often elongated on the dorsal and ventral portions of the head. On the thorax, striae are present, but they are less engraved with fewer punctures than in "S. richteri". On the petiole, the punctates are located on the sides. The postpetiole, when viewed above, has a strong shagreen with distinct transverse punctostriae. The sides are covered in deep punctures, where they appear smaller but deeper. In "S. richteri", the punctures are larger and more shallow. This gives a more opaque appearance to the surface. In some cases, punctostriae may be present around the rear portion. The pilosity appears similar to that of "S. richteri". These hairs are erect and vary in length, appearing long on each side of the pronotum and mesonotum; on the head, the long hairs are seen in longitudinal rows. Numerous appressed pubescent hairs are on the petiolar scale; this is the opposite in "S. richteri", as these hairs are sparse. Workers appear red and somewhat yellowish with a brown or completely black gaster. Gastric spots are sometimes seen in larger workers, where they are not as brightly coloured as those in "S. richteri". The gastric spot usually covers a small portion of the first gastric tergite. The thorax is concolorous, ranging from light reddish-brown to dark-brown. The legs and coxae are usually lightly shaded. The head has a consistent colour pattern in large workers, with the occiput and vertex appearing brown. Other parts of the head, including the front, genae, and the central region of the clypeus, are either yellowish or yellowish brown. The anterior borders of the genae and mandibles are dark-brown; they also both appear to share the same coloured shade with the occiput. The scapes and funiculi range from being the same colour as the head or shares the same shade with the occiput. Light-coloured areas of the head in small to medium-sized workers is restricted to only the frontal region, with a dark mark resembling an arrow or rocket being present. On occasion, nests may have a series of different colours. For example, workers may be much darker, and the gastric spot may be completely absent or appear dark-brown.


title: Red imported fire ant

text: Queens have a head length of and a width of . The scapes measure and the thorax is . The head is almost indistinguishable from "S. richteri", but the occipital excision is less crease-like and the scapes are considerably shorter. Its petiolar scale is convex and resembles that of "S. richteri". The postpetiole has straight sides that never concave, unlike in "S. richteri" where they concave. The thorax is almost identical, but the clear space between the metapleural striate area and propodeal spiracles is either a narrow crease or not present. The side portions of the petiole are punctate. The sides of the postpetiole are opaque with punctures present, but no irregular roughening is seen. The anterior of the dorsum is shagreen, and the middle and rear regions bear transverse puncto-striae. All these regions have erect hairs. The anterior portions of both the petiole and postpetiole have appressed pubescence that is also seen on the propodeum. The colour of the queen is similar to that of a worker: the gaster is dark brown and the legs, scapes, and thorax are light brown with dark streaks on the mesoscutum. The head is yellowish or yellowish-brown around the central regions, the occiput and mandibles are a similar colour to the thorax, and the wing veins range from colourless to pale brown. Males appear similar to "S. richteri", but the upper borders of the petiolar scales are more concave. In both species, the postpetiole's and petiole's spiracles strongly project. The whole body of the male is concolorous black, but the antennae are whitish. Like the queen, the wing veins are colourless or pale brown.


title: Red imported fire ant

text: The red imported ant can be misidentified as the similar-looking "S. richteri". The two species can be distinguished from each other through morphological examinations of the head, thorax, and postpetiole. In "S. richteri", the sides of the head are broadly elliptical and the cordate shape seen in the red imported fire ant is absent. The region of the occipital lobes that are situated nearby the midline and occipital excision appear more crease-like in "S. richteri" than it does in the red imported fire ant. The scapes of "S. richteri" are longer than they are in the red imported fire ant, and the pronotum has strong angulate shoulders. Such character is almost absent in the red imported fire ant. A shallow but sunken area is only known in the larger workers of "S. richteri", which is located in the posterior region of the dorsum of the pronotum. This feature is completely absent in larger red imported fire ant workers. The red imported fire ant's promesonotum is strongly convex, whereas this feature is weakly convex in "S. richteri". Upon examination, the base of the propodeum is elongated and straight in "S. richteri", while convex and shorter in the red imported fire ant. It also has a wide postpetiole with either straight or diverging sides. The postpetiole in "S. richteri" is narrower with converging sides. In "S. richteri", the transverse impression on the posterodorsal portion of the postpetiole is strong, but weak or absent in the red imported fire ant. As well as that, "S. richteri" workers are 15% larger than red imported fire ant workers, are blackish-brown, and have a yellow stripe on the dorsal side of the gaster.


title: Red imported fire ant

text: Eggs are tiny and oval-shaped, remaining the same size for around a week. After one week, the egg assumes the shape of an embryo and forms as a larva when the egg shell is removed. Larvae measure . They show a similar appearance to "S. geminata" larvae, but they can be distinguished by the integument with spinules on top of the dorsal portion of the posterior somites. The body hairs measure with a denticulate tip. The antennae both have two or three sensilla. The labrum is smaller with two hairs on the anterior surface that are . The maxilla has a sclerotised band between the cardo and stipes. The labium also has a small sclerotised band. The tubes of the labial glands are known to produce or secrete a proteinaceous substance that has a rich level of digestive enzymes, which includes proteases and amylases that function as an extraintestinal digestion of solid food. The midgut also contains amylases, roteases and upases. The narrow cells in its reservoir have little to no function in secretion. The pupae resemble adults of any caste, except that their legs and antennae are held tightly against the body. They appear white, but over time, the pupae turns darker when they are almost ready to mature.


title: Red imported fire ant

text: Four larval instars have been described based on distinctive morphological characters. The larvae of the minor and major workers are impossible to distinguish before the final instar, when size differences become apparent. Upon pupation a wider head width difference between castes become more evident. Reproductive larvae are larger than worker larvae, and present discrete morphological differences in mouthparts. Fourth-instar larvae of males and queens can be differentiated based on their relative shape and body coloration, and also internal gonopodal imaginal discs can differ.


title: Red imported fire ant

text: The red imported fire ant is polymorphic with two different castes of workers: minor workers and major workers (soldiers). Like many ants that exhibit polymorphism, young, smaller ants do not forage and tend to the brood, instead, while the larger workers go out and forage. In incipient colonies, polymorphism does not exist, but instead they are occupied by monomorphic workers called "minims" or "nanitics". The average head-width in tested colonies increases during the first six months of development. In five-year-old colonies, the head width of minor workers decreases, but for major workers, the head-width remains the same. The total weight of a major worker is twice that of a minor worker when they first arrive, and by six months, major workers are four times heavier than minor workers. Once major workers develop, they can make up a large portion of the workforce, with as many as 35% being major workers in a single colony. This does not affect colony performance, as polymorphic colonies and nests with small workers produce broods at roughly the same rate, and polymorphism is not an advantage or disadvantage when food sources are not limited. However, polymorphic colonies are more energetically efficient, and under conditions where food is limited, polymorphism may provide a small advantage in brood production, but this depends on the levels of food stress.


title: Red imported fire ant

text: As worker ants grow to larger sizes, the shape of the head changes, due to the head length growing at the same time as the total body length, and the head width may grow by 20%. The length of the antennae only grows slowly; the antennae may only grow 60% longer by the time the body doubles its length, thus the relative antennal length decreases by 20% as the length of the body doubles. All individual legs of the body are isometric with body length meaning that even when the length of the body doubles, the legs will also double. However, not all of the legs are the same length; the prothoracic portion accounts for 29% of leg length, the mesothoracic 31%, and the metathoracic 41%. The first two pairs of legs are of equal length to one another, whereas the final pair is longer. Overall, the morphological appearance of a worker changes dramatically when it grows larger. The head exhibits the greatest shape change and the height of the alinotum grows quicker than its length, where a height/length ratio of 0.27 in minor workers and 0.32 in major workers is seen. Due to this, larger workers tend to have a humped-shape and robust alinotum in contrast to smaller workers. No petiole segment exhibits any change in shape as the size of the body changes. The width of the gaster grows more rapidly than its length, where the width may be 96% of its length but increases to 106%.


title: Red imported fire ant

text: Like other insects, the red imported fire ant breathes through a system of gas-filled tubes called tracheae connected to the external environment through spiracles. The terminal tracheal branches (tracheoles) make direct contact with internal organs and tissue. The transport of oxygen to cells (and carbon dioxide out of cells) occurs through diffusion of gases between the tracheoles and the surrounding tissue and is assisted by a discontinuous gas exchange. As with other insects, the direct communication between the tracheal system and tissues eliminates the need for a circulating fluid network to transport O. Thus, red imported fire ants and other arthropods can have a modest circulatory system though they have highly expensive metabolic demands.


title: Red imported fire ant

text: The excretory system consists of three regions. The basal region has three cells found within the posterior portion of the midgut. The anterior and superior cavities are formed by the bases of four Malpighian tubules. The superior cavity opens into the lumen of the small intestine. The rectum is a large but thin-walled sac that occupies the posterior fifth of the larvae. The release of waste is controlled by the rectal valves that lead to the anus. Sometimes, the larvae secrete a liquid that consists of uric acid, water and salts. These contents are often carried outside by workers and ejected, but colonies under water stress may consume the contents. In the reproductive system, queens release a pheromone that prevents dealation and oogenesis in virgin females; those tested in colonies without a queen begin oocyte development after dealation and take up the egg-laying role. Flight muscle degeneration is initiated by mating and juvenile hormones, and prevented by corpus allatectomy. Histolysis begins with the dissolution of the myofibril and the slow breakdown of the myofilaments. Such dissolution continues until it reaches the only free Z-line materials, which would also disappear; only the nuclei and lamellar bodies remain. In one study, the amino acids increase in the hemolymph after insemination.


title: Red imported fire ant

text: The glandular system contains four glands: the mandibular, maxillary, labial, and postpharyngeal glands. The postpharyngeal is well developed in the queen, while the other glands are larger in workers. The postpharyngeal gland functions as a vacuum to absorb fatty acids and triglycerides, as well as a gastric caecum. The functions of the other glands remain poorly understood. In one study discussing the enzymes of the digestion system of adult ants, lipase activity was found in the mandibular and labial glands, as well as invertase activity. The Dufour's gland found in the ant acts as a source of trail pheromones, although scientists believed the poison gland was the source of the queen pheromone. The neurohormone pheromone biosynthesis activating neuropeptide is found in the ant that activates the biosynthesis of pheromones from the Dufour's gland. The spermatheca gland is found in queens, which functions in sperm maintenance. Males appear to lack these glands, but those associated with its head are morphologically similar to those found in workers, but these glands may act differently.


title: Red imported fire ant

text: The ant faces many respiratory challenges due to its highly variable environment, which can cause increased desiccation, hypoxia, and hypercapnia. Hot, humid climates cause an increase in heart rate and respiration which increases energy and water loss. Hypoxia and hypercapnia can result from red imported fire ant colonies living in poorly ventilated thermoregulatory mounds and underground nests. Discontinuous gas exchange (DGE) may allow ants to survive the hypercapnic and hypoxic conditions frequently found in their burrows; it is ideal for adapting to these conditions because it allows the ants to increase the period of O intake and CO expulsion independently through spiracle manipulation. The invasion success of the red imported fire ant may possibly be related to its physiological tolerance to abiotic stress, being more heat tolerant and more adaptable to desiccation stress than "S. richteri". This means that the ant is less vulnerable to heat and desiccation stress. Although "S. richteri" has higher water body content than the red imported fire ant, "S. richteri" was more vulnerable to desiccation stress. The lower sensitivity to desiccation is due to a lower water loss rate. Colonies living in unshaded and warmer sites tend to have a higher heat tolerance than those living in shaded and cooler sites.


title: Red imported fire ant

text: Metabolic rate, which indirectly affects respiration, is also influenced by environmental temperature. Peak metabolism occurs at about 32 °C. Metabolism, and therefore respiration rate, increases consistently as temperature increases. DGE stops above 25 °C, although the reason for this is currently unknown.


title: Red imported fire ant

text: Respiration rate also appears to be influenced significantly by caste. Males show a considerably higher rate of respiration than females and workers, due, in part, to their capability for flight and higher muscle mass. In general, males have more muscle and less fat, resulting in a higher metabolic O demand.


title: Red imported fire ant

text: While the metabolic rate is highest at 32 °C, colonies often thrive at slightly cooler temperatures (around 25 °C). The high rate of metabolic activity associated with warmer temperatures is a limiting factor on colony growth because the need for food consumption is also increased. As a result, larger colonies tend to be found in cooler conditions because the metabolic demands required to sustain a colony are decreased.


title: Red imported fire ant

text: Red imported fire ants are native to the tropical areas of Central and South America, where they have an expansive geographical range that extends from southeastern Peru to central Argentina, and to the south of Brazil. In contrast to its geographical range in North America, its range in South America is significantly different. It has an extremely long north–south range, but a very narrow east–west distribution. The northernmost record of the red imported fire ant is Porto Velho in Brazil, and its southernmost record is Resistencia in Argentina; this is a distance of about . In comparison, the width of its narrow range is about , and this is most likely narrower into southern Argentina and Paraguay and into the northern areas of the Amazon River basin. Most known records of the red imported fire ant are around the Pantanal region of Brazil. However, the interior of this area has not been examined thoroughly, but it is certain that the species occurs in favourable locations around it. The Pantanal region is thought to be the original homeland of the red imported fire ant; hydrochore dispersal via floating ant rafts could easily account for the far south populations around the Paraguay and Guaporé Rivers. The western extent of its range is not known exactly, but its abundance there may be limited. It may be extensive in easternmost Bolivia, owing to the presence of the Pantanal region.


title: Red imported fire ant

text: These ants are native to Argentina, and the red imported fire ant most likely came from here when they first invaded the United States; in particular, populations of these ants have been found in the provinces of Chaco, Corrientes, Formosa, Santiago del Estero, Santa Fe, and Tucumán. The northeastern regions of Argentina are the most credible guess where the invading ants originate. In Brazil, they are found in northern Mato Grosso and in Rondônia and in São Paulo state. The red imported fire ant and "S. saevissima" are parapatric in Brazil, with contact zones known in Mato Grosso do Sul, Paraná state and São Paulo. In Paraguay they are found throughout the country, and have been recorded in Boquerón, Caaguazú, Canindeyú, Central, Guairá, Ñeembucú, Paraguarí, and Presidente Hayes departments; Trager claims that the ant is distributed in all regions of the country. They are also found in a large portion of northeastern Bolivia and, to a lesser extent, in northwestern Uruguay.


title: Red imported fire ant

text: The red imported fire ant is able to dominate altered areas and live in a variety of habitats. It can survive the extreme weather of the South American rain forest, and in disturbed areas, nests are seen frequently alongside roads and buildings. The ant has been observed frequently around the floodplains of the Paraguay River. In areas where water is present, they are commonly found around: irrigation channels, lakes, ponds, reservoirs, rivers, streams, riverbanks, and mangrove swamps. Nests are found in agricultural areas, coastlands, wetlands, coastal dune remnants, deserts, forests, grasslands, natural forests, oak woodland, mesic forest, leaf-litter, beach margins, shrublands, alongside rail and roads, and in urban areas. In particular, they are found in cultivated land, managed forests and plantations, disturbed areas, intensive livestock production systems, and greenhouses. Red imported fire ants have been found to invade buildings, including medical facilities. In urban areas, colonies dwell in open areas, especially if the area is sunny. This includes: urban gardens, picnic areas, lawns, playgrounds, schoolyards, parks, and golf courses. In some areas, there are on average 200 mounds per acre. During winter, colonies move under pavements or into buildings, and newly mated queens move into pastures. Red imported fire ants are mostly found at altitudes between above sea level.


title: Red imported fire ant

text: Mounds range from small to large, measuring in height and in diameter with no visible entrances. Workers are only able to access their nests thorugh a series of tunnels that protrude from the central region. Such protrusions can span up to 25 feet away from the central mound, either straight down in to the ground or, more commonly, sideways from the original mound. Constructed from soil, mounds are oriented so that the long portions of the mound face toward the sun during the early morning and before sunset. Mounds are usually oval-shaped with the long axis of the nest orientating itself in a north–south direction. These ants also spend large amounts of energy in nest construction and transporting brood, which is related with thermoregulation. The brood is transported to areas where temperatures are high; workers track temperature patterns of the mound and do not rely on behavioural habits. Inside nests, mounds contain a series of narrow horizontal tunnels, with subterranean shafts and nodes reaching grass roots below the surface; these shafts and nodes connect the mound tunnels to the subterranean chambers. These chambers are about 5 cm (0.77 inch) and reach depths of . The mean number of ants in a single subterranean chamber is around 200.


title: Red imported fire ant

text: Red imported fire ants are among the worst invasive species in the world. Some scientists consider the red imported fire ant to be a "disturbance specialist"; human disturbance to the environment may be a major factor behind the ants' impact (fire ants tend to favour disturbed areas). This is shown through one experiment, demonstrating that mowing and plowing in studied areas diminished the diversity and abundance of native ant species, whereas red imported fire ants found on undisturbed forest plots had only diminished a couple of species.