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Talk:Radiocarbon dating

Reference 53
Proper bibliographic information is missing for Ref.53 of the current version, "Pasquier-Cardina et al. (1999), pp. 200–201." My guess is, it was meant to cite a paper by Pasquier-Cardin et al., not Pasquier-Cardina; However, unfortunately, I'm unable to access the paper beyond its abstract. Can anybody confirm the content and revise the citation? Thanks. --Deer hunter (talk) 15:17, 14 January 2023 (UTC)
 * Thanks for catching that; that is indeed the right paper. I've fixed the citation; let me know if that looks OK. Mike Christie (talk - contribs -  library) 15:31, 14 January 2023 (UTC)
 * Thanks for your prompt improvement! --Deer hunter (talk) 15:37, 14 January 2023 (UTC)

The origin of the neutron?
The origin of 14C from the nuclear reaction with a neutron is undisputed today. But where do the neutrons come from? Since neutrons decay with a half-life comparable to the transit time of light from the Sun, objects that are much farther away cannot be the explanation. Franz Scheerer aus Wiesbaden (talk) 11:36, 25 April 2023 (UTC)
 * See this section of the article; they are created in the atmosphere by cosmic rays. Mike Christie (talk - contribs - library) 12:17, 25 April 2023 (UTC)
 * I found there:
 * "They originate from the Sun, from outside of the Solar System in our own galaxy, and from distant galaxies."
 * So, I think the neutrons originate from the Sun, because the distance to objects outside of the Solar System or from distant galaxies are much too far away. Franz Scheerer aus Wiesbaden (talk) 14:34, 25 April 2023 (UTC)
 * The cosmic rays originate from those places. They strike the atmosphere (typically Nitrogen-14) and knock off a neutron. MrOllie (talk) 14:42, 25 April 2023 (UTC)
 * If you knock off a neutron from Nitrogen-14 you create Nitrogen-13, which decays to Carbon-13. I don't think, that this was observed on Earth. Franz Scheerer aus Wiesbaden (talk) 10:15, 26 April 2023 (UTC)
 * See Neutron for more details; there are sources cited there which give more information. There are multiple pathways that generate neutrons, including spallation of nitrogen nuclei. Mike Christie (talk - contribs -  library) 10:26, 26 April 2023 (UTC)

Decay graph for C14
I've removed the graph for C14 decay, which was just added to the lead, for a couple of reasons. I think a graph like this is a good idea but I have a couple of questions. (There's a spelling error in the caption, FYI, for when it's re-added.) One problem is I tried to check the source and am getting a security error, so there's apparently a problem (probably temporary) with the website. , if you have access, can you explain what makes that website reliable? A second issue is that I don't think it belongs in the lead -- I think the "Principles" section would be a better fit, since that's where decay is covered. I also wonder if it's necessary to be clear what half-life is used for the graph, since the Libby half-life is used in C14 calculations. Presumably this graph uses 5730 years, which is appropriate for the physical details. And I think the caption needs to be more explicit about what it shows rather than just saying there's a correspondence. Mike Christie (talk - contribs - library) 10:15, 22 May 2023 (UTC)

 * I couldn't access the website either, so I probably withhold from adding the image for now. CactiStaccingCrane (talk) 10:22, 22 May 2023 (UTC)

Lead image
The first half of the article is quite text-heavy. It would be nice to find an engaging image for the lead. There aren't a lot of great options on Commons, though. Maybe File:Mummy tooth sampling.jpg, but I'm not sure having an image of human remains right up front is wise? – Joe (talk) 18:12, 22 June 2023 (UTC)
 * I agree it would be nice to have something there. I think a picture of Libby would be ideal but I've been unable to find a free one.  This might be dramatic; having something that has been radiocarbon dated and which is clearly old seems a reasonable option. Mike Christie (talk - contribs -  library) 18:23, 22 June 2023 (UTC)
 * The reflection on the glass is a bit of a shame with that one. Also it's a bit odd using something so amenable to dendro dating... but maybe that's just me. Would the Dead Sea Scrolls be too obvious? – Joe (talk) 15:42, 23 June 2023 (UTC)
 * That could work. There's already an image of one of the scrolls in the article; we could move that to the top or perhaps use this one instead? Mike Christie (talk - contribs -  library) 16:01, 23 June 2023 (UTC)
 * I think that's a good idea. Nice to have two. – Joe (talk) 15:14, 25 June 2023 (UTC)

Impact
The first sentence of the last paragraph in the article (under the section heading of "Impact" states: "Researchers have studied other radioactive isotopes created by cosmic rays to determine if they could also be used to assist in dating objects of archaeological interest; such isotopes include 3He, 10Be, 21Ne, 26Al, and 36Cl.  Thus, this sentence asserts that Helium-3 and Neon-21 are radioactive.  They are not; they are stable isotopes. 47.205.67.147 (talk) 17:09, 8 July 2023 (UTC)
 * You're right, of course; I've removed "radioactive" from that sentence. I don't think it's the place to go into how a non-radioactive cosmogenic isotope could be used for dating, so I don't think more is needed.  Thanks for pointing out the error. Mike Christie (talk - contribs -  library) 17:59, 8 July 2023 (UTC)

Tree rings
I am reading Jennifer French's 2021 Palaeolithic Europe, which covers the period down to 15,000 years BP, and on page 215 she comments that radiocarbon dates for her period are of inadequate precision to trace some demographic processes because they are before "the more reliable dendrochronology-based part of the 14C calibration curve", which only goes back to ~13,910 cal BP as of 2020 (see ). The article does discuss tree ring calibration and in brackets that it goes back 13,900 years, but unless I have missed the relevant passage I do not think it spells out clearly that radiocarbon dating is more accurate for this period than for earlier ones for which exact proxies are not available. Do you agree and do you think this is worth spelling out? Dudley Miles (talk) 19:36, 24 October 2023 (UTC)
 * You're right that the article doesn't go into this. It would certainly be worth putting something into the radiocarbon calibration article, which is currently just the leftovers from this article.  I would like to add something here too, but I think it's going to be tricky to get it right.  If we're going to discuss how accurate the calibration curve is we shouldn't restrict ourselves to the statement that the dendochronology part is the most accurate; as I understand it the error bars get larger as you go back in time because the smaller amounts of 14C automatically decrease the accuracy.  I would imagine there is also material to be found on the relative accuracy of the varve data and so on.  The articles on the various IntCal curves probably cover this but I'm not sure I have the technical savvy to distill the relevant bits out accurately -- those articles are technical discussions, not survey works. Mike Christie (talk - contribs -  library) 02:01, 25 October 2023 (UTC)
 * I agree that the diminishing accuracy as dates get older should be covered and I have not found a source discussing this, but I do not think this is a reason for not briefly covering dendro dates. There is a good source for this at, which also mentions Miyake events, which are not currently mentioned in the Wiki article. How about "The continuous sequence of tree ring dates goes back to 13,910 BP as of 2020, and this provides close to annual dating for much of the period, reduced where there are calibration plateaus, and increased when short term $14$C spikes due to Miyake events provide additional correlation. Radiocarbon dating earlier than the continuous tree ring sequence relies on correlation with less accurate proxies and has wider error bars." Dudley Miles (talk) 10:03, 25 October 2023 (UTC)

Just looking at the abstract I don't think we can say "close to annual dating for much of the period"; the source only has "for certain time ranges", which could mean less than half of the range. Perhaps just "for part of the period" would work. Or does the body of the cited article support "much of"? Again just looking at the abstract I think we'd also need more support for "wider error bars", but perhaps French's book would provide that if the body of the article doesn't. If you agree, go ahead and make the change -- I'm off to work in a few minutes. Mike Christie (talk - contribs - library) 11:34, 25 October 2023 (UTC)

 * The first link was to the abstract, but the reference was to the full article. Can you see whether you think this supports my wording. Dudley Miles (talk) 12:01, 25 October 2023 (UTC)
 * Will look later today. Mike Christie (talk - contribs - library) 12:07, 25 October 2023 (UTC)
 * , sorry about the delay getting back to you on this. I agree that the article covers this.  For the last phrase of your proposed sentence, "less accurate proxies and has wider error bars", are you relying on just the fact that the tree-ring data is said to have become more accurate, or was there a specific place in the article that supports this?  I think it's OK either way but the latter would be ideal.  Mike Christie (talk - contribs -  library) 10:04, 29 October 2023 (UTC)
 * . I have looked again at the source article. It frequently refers to using dendro dates for the period where they are available and other records (not proxies) for earlier periods. I think this covers your point. There is no reference to error bars. My amended suggestions is "The continuous sequence of tree ring dates for the northern hemisphere goes back to 13,910 BP as of 2020, and this provides close to annual dating for IntCal20 for much of the period, reduced where there are calibration plateaus, and increased when short term $14$C spikes due to Miyake events provide additional correlation. Radiocarbon dating earlier than the continuous tree ring sequence relies on correlation with less accurate records." I think "more approximate" would be better than "less accurate", but I am not sure whether it is good English. What do you think? Dudley Miles (talk) 11:26, 29 October 2023 (UTC)
 * That seems good to me, and I think "more approximate" and "less accurate" are both acceptable; use whichever you prefer. Mike Christie (talk - contribs - library) 11:45, 29 October 2023 (UTC)
 * Looking at the article I think there is an error. It says "The IntCal20 data includes separate curves for the northern and southern hemispheres". The source says "For calibrating atmospheric samples from the Northern Hemisphere, the new curve is called IntCal20. This is accompanied by associated curves SHCal20 for the Southern Hemisphere, and Marine20 for marine samples." So IntCal20 is just for the northern hemisphere, not covering both as the Wiki article says. Do you agree? Dudley Miles (talk) 14:29, 29 October 2023 (UTC)
 * Yes -- I think when I wrote that I thought "IntCal20" was used as a shorthand for the whole 2020 recalibration as well as the NH curve, but even if that's true I think it would be better to rephrase to avoid the ambiguity. Mike Christie (talk - contribs - library) 14:56, 29 October 2023 (UTC)

Recent edits to the lead
One reason I reverted is that the changes led to repetition -- the mention of the Nobel Prize and date range of the dating method are already in the lead. If they're to be moved up, they shouldn't also be mentioned lower down in the lead. Another reason is that the existing lead structure mentions them where they come naturally. Yes, they're important points, but I don't think it's necessary to mention them right at the top -- particularly the Nobel Prize.

Can we please follow the WP:BRD recommendations? Once an edit is reverted, it should be discussed on the talk page rather than redone. This page has other watchers who may have an opinion; let's see what they think of the proposed changes first. Mike Christie (talk - contribs - library) 02:51, 15 November 2023 (UTC)

 * May I suggest, that we keep the year range and the Nobel Prize in the first paragrpah, and remove them from the rest of the Intro.  I strongly feel, that the useful range of the method must be in the very first paragraph ,because the general public  thinks, that early hominid (i.e. Australopithecus) remains were carbon-dated. Walter Tau (talk) 03:04, 15 November 2023 (UTC)

 * Obviously the two repetitions have to be removed somehow. The second long paragraph is a bit convoluted and putting the two mentions of Libby (invention + Nobel) into a single sentence would help. I also suggest removing some material from the second paragraph (the 98% and the "special preparation methods") as I think such fine detail doesn't need to be in the lead. I don't find Walter's reason for mentioning the time period in the first paragraph convincing; the second paragraph is soon enough though it could be written better. Zerotalk 03:18, 15 November 2023 (UTC)
 * I don't think these two details are so important that they need to be mentioned in the first paragraph. Also, Walter Tau's edit introduced a lower bound to the range (ca. in the range between 1,000 and 50,000 years) which is unsourced and incorrect: with bomb curve dating, you can date the cells in your own body, if you want. – Joe (talk) 08:40, 15 November 2023 (UTC)

title: Talk:Radiocarbon dating


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Clive Sinclair

Sir Clive Marles Sinclair (30 July 1940 – 16 September 2021) was an English entrepreneur and inventor, best known for being a pioneer in the computing industry and also as the founder of several companies that developed consumer electronics in the 1970s and early 1980s.

After spending several years as assistant editor of Instrument Practice, Sinclair founded Sinclair Radionics Ltd in 1961. He produced the world's first slimline electronic pocket calculator (the Sinclair Executive) in 1972. Sinclair then moved into the production of home computers in 1980 with Sinclair Research Ltd, producing the Sinclair ZX80 (the UK's first mass-market home computer for less than £100) and in the early 1980s, the ZX81, ZX Spectrum and the Sinclair QL. Sinclair Research is widely recognised for its importance in the early days of the British and European home computer industry, as well as helping to give rise to the British video game industry.

Sinclair also had several commercial failures, including the Sinclair Radionics Black Watch wristwatch, the Sinclair Vehicles C5 battery electric vehicle, and the Sinclair Research TV80 flatscreen CRT handheld television set. The failure of the C5, along with a weakened computer market, forced Sinclair to sell most of his companies by 1986. Through 2010, Sinclair concentrated on personal transport, including the A-bike, a folding bicycle for commuters which was small enough to fit in a handbag. He also developed the Sinclair X-1, a revised version of the C5 electric vehicle, which never made it to the market.

Sinclair was appointed Knight Bachelor in the 1983 Birthday Honours for his contributions to the personal computer industry in the UK.

Early life, family and education
Sinclair's father and grandfather were engineers; both had been apprentices at the shipbuilders Vickers. His grandfather George Sinclair was a naval architect who got the paravane, a mine sweeping device, to work. George Sinclair's son, George William "Bill" Sinclair, wanted to take religious orders or become a journalist. His father suggested he train as an engineer first; Bill became a mechanical engineer and remained in the field. At the outbreak of World War II in 1939, he was running his own machine tools business in London, and later worked for the Ministry of Supply.

Clive Sinclair was born to George Sinclair and Thora Edith Ella Marles on 30 July 1940, in Ealing, Middlesex. He and his mother left London for safety to stay with an aunt in Devon, where they eventually moved to Teignmouth. A telegram arrived shortly afterwards, bringing the news that their home in Ealing had been bombed. Sinclair's father found a house in Bracknell in Berkshire. His brother Iain was born in 1943 and his sister Fiona in 1947.

Sinclair attended Boxgrove Preparatory School, excelling in mathematics. Sinclair had little interest in sports and found himself out of place at school. By the time he was ten, his father had financial problems. He had branched out from machine tools and planned to import miniature tractors from the U.S.; he had to give up the business. Because of his father's problems, Sinclair had to move school several times. After a time at Reading School, Sinclair took his O-levels at Highgate School in London in 1955, and his A-levels and S-levels in physics, pure maths, and applied maths at St. George's College, Weybridge.

During his early years, Sinclair earned money mowing lawns and washing up in a café, earning 6d (2½p) more than the permanent staff. Later he went for holiday jobs at electronic companies. At Solartron he inquired about the possibility of electrically propelled personal vehicles. Sinclair applied for a holiday job at Mullard and took one of his circuit designs; he was rejected for precociousness. While still at school he wrote his first article for Practical Wireless.

After he left school at the age of 18, he sold miniature electronic kits by mail order to the hobby market.

Sinclair Radionics

Sinclair's Micro Kit was formalised in an exercise book dated 19 June 1958, three weeks before his A-levels. Sinclair drew a radio circuit, Model Mark I, with a components list: cost per set 9/11 (49½p), plus coloured wire and solder, nuts and bolts, plus celluloid chassis (drilled) for nine shillings (45p). Also in the book are the advertisement rates for Radio Constructor at the time (9d (3¾p)/word, minimum 6/- (30p)) and Practical Wireless (5/6 (27½p) per line or part line). Sinclair estimated producing 1,000 a month, placing orders with suppliers for 10,000 of each component to be delivered.

Sinclair wrote a book for Bernard's Publishing, Practical transistor receivers Book 1, which appeared in January 1959. It was re-printed late that year and nine times subsequently. His practical stereo handbook was published in June 1959 and reprinted seven times over 14 years. The last book Sinclair wrote as an employee of Bernard's was Modern Transistor Circuits for Beginners, published in May 1962. At Bernard Babani, he wrote 13 constructor books.

In 1961, Sinclair registered Sinclair Radionics Ltd. His original choice, Sinclair Electronics, had been taken; Sinclair Radio was available but did not sound right. Sinclair Radionics was formed on 25 July 1961. Sinclair made two attempts to raise startup capital to advertise his inventions and buy components. He designed PCB kits and licensed some technology. Then he took his design for a miniature transistor pocket radio and sought a backer for its production in kit form. Eventually he found someone who agreed to buy 55% of his company for £3,000, but the deal didn't finalise.

Sinclair, unable to find capital, joined United Trade Press (UTP) as technical editor of Instrument Practice. Sinclair appeared in the publication as an assistant editor in March 1962. Sinclair described making silicon planar transistors, their properties and applications and hoped they might be available by the end of 1962. Sinclair undertook a survey of semiconductor devices for Instrument Practice, which appeared in four sections between September 1962 and January 1963.

His last appearance as assistant editor was in April 1969. Through UTP, Sinclair had access to thousands of devices from 36 manufacturers. He contacted Semiconductors Ltd (who at that time sold semiconductors made by Plessey) and ordered rejects to repair. He produced a design for a miniature radio powered by a couple of hearing aid cells and made a deal with Semiconductors to buy its micro-alloy transistors at 6d (2½p) each in boxes of 10,000. He then carried out his own quality control tests, and marketed his renamed MAT 100 and 120 at 7s 9d (38¾p) and 101 and 121 at 8s 6d (42½p).

By the late 1960s and early 1970s, Sinclair Radionics was producing handheld electronic calculators, miniature televisions, and the digital Black Watch wristwatch. The latter product, introduced in 1975, was a significant failure for Sinclair: in addition to being unable to meet demand, the watch itself was found to be inaccurate and difficult to service, and its battery life was too short. Sinclair Radionics suffered its first financial loss in 1975–1976, and Sinclair sought potential investors to help recover the lost funds. He eventually worked with the National Enterprise Board (NEB), which bought a 43% interest in the company in 1976, but this injection of funds was found to be too late as by this point, other companies were starting to make similar products at lower costs on the market. The NEB streamlined Sinclair Radionics' product line, selling off the watch and television lines, and brought in Norman Hewitt as a managing director to assist Sinclair. While Sinclair made efforts to work with Hewitt and the NEB, his relationship with these worsened, as the NEB had little faith in Sinclair's vision. By 1979, the NEB opted to break up Sinclair Radionics, holding its instruments division as Sinclair Electronics, and selling its television division to Binatone and its calculator division to ESL Bristol. Sinclair himself left the company at this point. Effectively NEB wrote off its estimated £7 million investment into Sinclair Radionics as a loss. Sinclair was given a golden handshake and an estimated £10,000 package with the dissolution of his company.

Sinclair Research

While Sinclair was dealing with the NEB and had seen problems developing, he had a former employee, Christopher Curry, establish a "lifeboat" company, called Science of Cambridge Ltd, in July 1977, called such as they were located near University of Cambridge, and planned for Curry to develop technology from ideas from the school. An early product from Science of Cambridge was a wrist calculator kit, which helped to keep the company financially afloat.

By the time that Sinclair had left Radionics and joined Curry at Science of Cambridge, inexpensive microprocessors had started appearing on the market. Sinclair came up with the idea of selling a microprocessor teaching kit, and in June 1978, Science of Cambridge launched the MK14 kit, based on the National SC/MP chip, in June 1978. As Sinclair began working on the MK14's successor, Curry was in discussions with Hermann Hauser, and opted to leave Science of Cambridge to co-found Acorn Computers with Hauser in 1978. Acorn became a direct competitor to Sinclair's products, with the Acorn System 75 as its answer to the MK14, effectively an MK14 chip with a keyboard.

To follow up on the MK14, Sinclair started looking to build a personal computer. At around that time (1979), premade systems such as the Commodore PET cost about £700, and Sinclair believed he could get the price of a system to under £100. Keeping the cost low was also essential for Sinclair to avoid his products from becoming outpriced by American or Japanese equivalents as had happened to several of the Sinclair Radionics products. In May 1979, Jim Westwood, a former Sinclair Radionics employee Sinclair hired for this new company, started the ZX80 project at Science of Cambridge; it was launched in February 1980 at £79.95 in kit form and £99.95 ready-built. The ZX80 was immediately successful, and besides sales in the UK, Sinclair also sought to introduce the computer into the United States. Science of Cambridge was subsequently renamed Sinclair Computers Ltd, and then again to Sinclair Research Ltd.

On hearing that the BBC was preparing to run a television series to teach viewers about computing and programming, both Sinclair and Curry pressured the BBC to choose computers from their respective companies to use as the primary tool. This pushed the development of the Sinclair ZX81 ahead as Sinclair's standard for the BBC. The ZX81 was launched at £49.95 in kit form and £69.95 ready-built, by mail order. Ultimately, the BBC chose Acorn and standardized on a successor to the Acorn Atom—originally named Acorn Proton, but ultimately branded as the BBC Micro. Despite losing out to the BBC, Sinclair's push had established the ZX80 and ZX81 as one of the most-sold brands of computers across the UK and the United States as well as establishing a deal with distribution in Japan with Mitsui. A number of user groups, magazines and third party accessories for both computers started to appear.

In February 1982, Timex obtained a licence to manufacture and market Sinclair's computers in the United States under the name Timex Sinclair. In April, the ZX Spectrum was launched at £125 for the 16 kB RAM version and £175 for the 48 kB version. It was the first computer in the ZX line to support colour output. The ZX Spectrum remained more affordable than other computers on the market, including the BBC Micro, VIC-20, and Apple II, and during a time of recession and high unemployment in the UK, was positioned by Sinclair as a low-cost home computer for productivity applications. However, it also proved to be a popular gift for teenagers and young adults that year. This led to a number of these young people learning to program on the ZX Spectrum, using its newfound colour support, to make quirky video games inspired by British humour which they sold through word of mouth and mail order. So-called "bedroom coders" using the ZX Spectrum gave rise to the start of the UK's video game industry. By 1984, over 3,500 games had been released for the ZX Spectrum.

The popularity of the ZX Spectrum spread to Western Europe. While Sinclair could not import into Eastern European countries still within the Soviet bloc at the time, numerous low-cost clones of the ZX Spectrum sprung up within these countries, further boosting the start of video game development by similar bedroom coders. The ZX Spectrum went on to become the UK's most-sold computer, selling more than 5 million units before it was discontinued in 1992. Sinclair Research computers accounted for 45% of the British market in 1984, including those from British and American companies.

The continued success of the computer market continued to help boost Sinclair Research's profit. In 1982, the company had a pre-tax profit of £9.2 million on a turnover of £27.6 million. Sinclair himself was estimated to a net value of over £100 million in 1983, two years after launching the first of the ZX computers. With the additional funds, Sinclair converted the Barker & Wadsworth mineral water bottling factory into the company's headquarters in 1982. In January 1983, American news magazine Time named the personal computer the 1982 "Machine of the Year," and Sinclair was one of six individuals from the computing industry who were spotlighted in the accompanying feature.

Sinclair Vehicles and market decline
As Sinclair Research continued to be successful, Sinclair launched a new company, Sinclair Vehicles Ltd., in March 1983 to develop electric vehicles, using 10% of the capital generated by Sinclair Research and selling some of his own shares to fund the new venture. Sinclair had an interest in electric vehicles since the 1970s at Sinclair Radionics, and had been working with Tony Wood Rogers, a former Radionics employee, since 1979 to start developing prototypes of a new vehicle for the market. The company's only product was the Sinclair C5 which launched in January 1985. The Sinclair C5 was considered a significant failure, having been developed without any market research. It was widely criticised and widely ridiculed for its high price, its toy-like appearance, lack of safety features and exposure to the elements, and the need for the user to pedal the vehicle up steeper hills. Whilst Sinclair had anticipated 100,000 C5's would be sold in the first year, only 14,000 units were produced and 4,500 sold before the C5 line was terminated in August that same year.

Another noted misfire for Sinclair was the Sinclair Research TV80, a flatscreen portable mini television utilising a cathode ray tube, which took several years to develop, and by the time the TV80 was ready for market in 1983, the Sony Watchman had been released in Japan in 1982. Furthermore, LCD television technology was already in advanced development to bypass the limitations of CRT. The TV80 was a commercial flop, only 15,000 units being produced. Despite these commercial failures, both the C5 and TV80 have since been considered products ahead of their time, with the C5 a precursor to the modern day electric car and the TV80 comparable to watching videos on smartphones.

Sinclair continued to direct Sinclair Research as they continued the ZX Spectrum line of computers through 1983 and 1984 as well as launching the Sinclair QL (short for Quantum Leap) brand in 1984 intended to compete with business lines of computers from IBM and Apple but at about half their cost. However, towards the end of 1984, the market for personal computers in the United Kingdom became cautious; Sinclair Research had entered into a small price war with Acorn Computers. The price drops meant that consumers saw these computers as more toys rather than productivity tools, and Sinclair Research missed its planned sales milestones for the 1984 holiday season. Into 1985, Acorn fell under investigation which propagated solvency concerns throughout the computer industry, including Sinclair Research. Robert Maxwell, the owner of The Daily Mirror and Pergamon Press, planned to help Sinclair Research through its £12 million acquisition via Pergamon's Hollis Brothers division, announced in June 1985. However the deal was aborted in August 1985 as Sinclair found an offer with the Dixons Group of only £10 million.

The lack of funds for Sinclair Research and the failure of the C5 created financial difficulties for Sinclair. Sinclair Vehicles was placed into receivership by October 1985, and in April 1986, Sinclair sold the bulk of Sinclair Research to Amstrad for £5 million. Sinclair Research Ltd. was reduced to an R&D business and holding company, with shareholdings in several spin-off companies, formed to exploit technologies developed by the company. These included Anamartic Ltd. (wafer-scale integration) and Cambridge Computer Ltd. (Z88 portable computer and satellite television receivers).

Later years
By 1990, Sinclair Research consisted of Sinclair and two other employees down from 130 employees at its peak in 1985, and its activities later concentrated on personal transport, including the Zike electric bicycle. By 2003, Sinclair Research was collaborating with Hong Kong-based firm Daka. A laboratory was set up for Daka near Croydon to develop products on a royalty basis. The two firms collaborated on a Sea Scooter and a wheelchair drive. In 1997, he invented the Sinclair XI, which was a radio the size of a 10p coin.

Sinclair had planned to introduce the Sinclair X-1 through Sinclair Research, another attempt at a personal electric vehicle following the Sinclair C5. The X-1 was first announced in 2010, and incorporated design aspects that the C5 had been panned for, including an open egg-like shell for the rider with a more ergonomic seat, a more powerful motor and larger battery storage, and an effectively lower cost accounting for inflation than the C5. However, the X-1 failed to reach the market.

Recognition
Sinclair received several honours for his contributions towards helping establish the personal computer industry in the United Kingdom. In 1983, he was awarded Honorary Degrees of Doctor of Science by the University of Bath, Heriot-Watt University and University of Warwick. He was knighted in the Queen's 1983 Birthday Honours List. In 1984, he was honoured by Imperial College London by being made a fellow. In 1988, London's National Portrait Gallery purchased a portrait of Sinclair by photographer Simon Lewis for its permanent collection.

Personal life
Sinclair was a poker player and appeared in the first three series of the Late Night Poker on Channel 4. He won the first series final of the Celebrity Poker Club spin-off. Sinclair was an atheist. He had an IQ of 159, and was a member of British Mensa, and chairman from 1980 to 1997. He also participated in marathons including several New York City Marathons.

Despite his involvement in computing, Sinclair did not use the Internet, stating that he does not like to have "technical or mechanical things around me" as it distracts from the process of invention. In 2010, he said that he did not use computers himself, and preferred using the telephone rather than email. In 2014, he predicted, "Once you start to make machines that are rivalling and surpassing humans with intelligence, it's going to be very difficult for us to survive. It's just an inevitability."

His first marriage with Ann ended in divorce after twenty years around 1985 due to the pressure from the ongoing financial issues he had with his companies. From his marriage with Ann, he had three children. In 2010 Sinclair married Angie Bowness, a former dancer at a Stringfellows nightclub and who represented England for Miss Europe 1995. This second marriage lasted for seven years before also ending in divorce.

On 16 September 2021, Sinclair died in London following an illness related to cancer that he had for over a decade. He was 81 years old. Sinclair was remembered on his death for his contributions towards computing and video games by numerous people, including Elon Musk, Satya Nadella, the Oliver Twins, Debbie Bestwick, Charles Cecil, and David Braben. A Times leader following his death described Sinclair as a tenacious inventor whose career was a triumph of perseverance similar to that of many of Britain's greatest inventors, such as Sir James Dyson and Alexander Graham Bell, 'who are a reminder that failure is an essential prelude to success'.

Publications
Sinclair authored electronics constructor books for Bernard Babani publishers:
 * Barnards 148 : Practical Transistor Receivers Book 1; 1959. (30 circuits)
 * Barnards 149 : Practical Stereo Handbook; 1959.
 * Barnards 151 : Transistor Receivers Book 2 - Transistor Superhet Receivers; 1960. (50 circuits)
 * Barnards 163 : Transistor Circuits Manual 2; 1960. (13 circuits)
 * Barnards 167 : Transistor Circuits Manual 3 - Eleven Tested Transistor Circuits using Prefabricated Circuit Units; 1960. (11 circuits)
 * Barnards 168 : Transistor Circuits Manual 4; 1960. (11 circuits)
 * Barnards 173 : Practical Transistor Audio Amplifiers for the Home Constructor Book 1; 1961. (32 circuits)
 * Barnards 174 : Transistor Subminiature Receivers Handbook for the Home Constructor; 1961.
 * Barnards 175 : Transistorized Test Equipment and Servicing Manual; 1961.
 * Barnards 176 : Transistor Audio Amplifier Manual; 1962. (32 circuits)
 * Barnards 177 : Modern Transistor Circuits for Beginners; 1962. (35 circuits)
 * Barnards 179 : Transistor Circuits Manual 5; 1963. (14 circuits)
 * Barnards 181 : 22 Tested Circuits Using Micro Alloy Transistors; 1963. (22 circuits)

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Clive Sinclair


text:
Talk:Sinclair Research

Merge needed
This article should be merged with the one at Sinclair Research, not just redirected from it. Otherwise the history of the article gets obscured. -- DrBob 18:05, 30 Sep 2004 (UTC)

Sounds like a good idea :-) how ??? Lmno 19:28, 30 Sep 2004 (UTC)

SRL?
Isn't SRL an abbreviation for a company suffix, like Ltd., or Inc.? --ZekeMacNeil 20:49, 31 Jan 2005 (UTC)

 * Well, there is the French "SARL" form of an LLC; might that be the one you were thinking of? --Wernher 02:14, 17 November 2005 (UTC)

Table alignment trouble
Hi, I have now put some long needed space around the profit/turnover table, to get some distance to the text flow, but after some trying and failing I'm still unable to get the table to align with the text's right margin. Anyone know how to do this? --Wernher 02:14, 17 November 2005 (UTC)

profit/turnover date
It says Revenue [up] £77.69 million GBP (1984) in the table, and yet the company is still alive. What is the point of listing a 1984 figure and trend? Is it the maximum profit they've made? --BACbKA 19:59, 18 February 2006 (UTC)
 * I've changed it to £102 million, the 1985 revenue - the highest revenue the company has ever made. Its not profit, its revenue/turnover. Its a good figure to include to show how large Sinclair did get at its peak in the 80s. Since then they've made increasing losses, as shown in the table. — Wackymacs 10:05, 19 February 2006 (UTC)

I see. I think that the infobox revenue field is used usually for displaying more current revenue figures, and I believe some folks will be puzzled (or imply right from this infobox field that the company is defunct) because the revenue here is over 10 years old, but 1) the template never says no to such practice 2) if somebody investigative enough is puzzled, this discussion at the talk page will answer their needs. Thanks for the clarification... --BACbKA 10:19, 19 February 2006 (UTC)
 * Well I'm not sure what you expect me to do - Sinclair is no longer a public company, and does not release financial figures and does not publicly trade on the London Stock Exchange. You could say the company is almost defunct really, just looking at the Sinclair website tells us Sinclair's been quiet in the past years. — Wackymacs 10:28, 19 February 2006 (UTC)

Sure thing. If I knew a better way I would have gone ahead and changed it... --BACbKA 10:49, 19 February 2006 (UTC) The last change to the article by Cedars, eliminating the green arrow, was an excellent move fully eliminating the problem for the any possibly confused future readers remaining. Now one really feels it is a static datum, not a live one. --BACbKA 17:39, 19 March 2006 (UTC)

A couple of suggestions
I'm a bit concerned about this article's current designation as a good article - there's a couple of things I think really need sorting out if it's to remain listed. First, 'facts and trivia' should be mentioned in the article anyway if they are actually notable. Putting them in their own section implies that they're not actually of great interest. Second, the list of cancelled projects would be much improved if it was made into prose. Otherwise it's fine. Worldtraveller 20:59, 29 April 2006 (UTC)

Merge proposal
As pointed out in the GA Reassessment, the section here on Sinclair Radionics probably should really be in the article about that company, with only a brief mention given here, as a background to the formation of Sinclair Research Ltd. Letdorf (talk) 13:30, 18 November 2008 (UTC).

 * I've now merged the Radionics material into that article, and left a brief summary of Sinclair Research pre-history. I've also corrected the apparent assumption that Sinclair Research was directly descended from Radionics; AIUI the two companies were quite separate entities (Radionics continued on its own path after Sir Clive resigned, and is now Thurlby-Thandar Instruments). Letdorf (talk) 11:22, 26 November 2008 (UTC).

The logo(s) of the two companies
After studying the two articles Sinclair Research and Sinclair Radionics for a few minutes, I can see how they deserve separate articles. However, the logo File:Sinclair.gif is being used in both articles, claiming both companies used the logo. Here in the US, this would never happen, since the whole point of a trademarked logo is to distinguish one company from another. Can anyone verify that the two companies both used the same logo? —Aladdin Sane (talk) 21:32, 8 November 2009 (UTC)

 * E.g. http://oldwww.nvg.ntnu.no/sinclair/audio/gallery/system4000_ad.jpg --Frodet (talk) 22:16, 8 November 2009 (UTC)

 * Yes, as Frodet has demonstrated, an inspection of relevant products or advertising material will confirm that the very same logo was used by Radionics and Research (and Amstrad after 1986). Letdorf (talk) 13:08, 9 November 2009 (UTC).

 * I think it's bizarre. But I bought Frodet's point when I saw it.  That's what an encyclopedia is for...learning stuff.  —Aladdin Sane (talk) 15:37, 9 November 2009 (UTC)

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title: Talk:Sinclair Research


text:
Dagobah

Dagobah is a fictional planet and eponymous star system appearing in the Star Wars films The Empire Strikes Back, Return of the Jedi, and Revenge of the Sith, and other media. It is depicted as a world of murky swamps, steaming bayous, and jungles, resembling Earth during the Carboniferous period. Dagobah is 14,410 kilometers in diameter with an orbital period of 341 days. Dagobah's climate and atmosphere consists of two seasons; a dry season, where the uplands become too hot for most life forms to survive; and a wet season, consisting of violent lightning storms, dense fog, and long periods of torrential rainfall. The Tash were a sentient species native to Dagobah.

The Dagobah System lies within the Dagobah subsector of the Sluis sector, located in the Outer Rim Territories galactic quadrant region; 50,250 light-years from Coruscant. The sun was called Dagobah Prime. It is noted as being one of the purest places in the galaxy, incredibly strong in the living force, and being chosen by Jedi Yoda as the planet to go into exile on to mask his presence and avoid discovery by the Galactic Empire.

Depiction
The similarly mono-thematic "swampy, fog-shrouded planet of Mimban" appearing in the novel Splinter of the Mind's Eye, published between the films Star Wars and The Empire Strikes Back, "might have inspired the production design for Dagobah".

Film
Dagobah was originally featured in the 1980 film The Empire Strikes Back. In its first appearance, the main protagonist of the film, Luke Skywalker, is attempting to land his X-wing starfighter on the planet and is met with a dense fog causing him to crash land in a small bayou. Shortly after his landing, the Jedi Master Yoda is introduced during his time in exile. Yoda reluctantly agrees to train Skywalker and during his training many aspects of the planet's environment are utilized. Moss-covered rocks are used for training in telekinesis, the undergrowth makes treks through the jungles more challenging, and vines hanging from tall trees are used as means to get across small bodies of water and other obstacles. Skywalker is shown to sense the strength of the Force in a particular cave on the planet which Yoda tells him to go into. Inside the cave, Skywalker is met with a mental challenge the dark side of the Force developed for him.

The planet is also seen briefly in Return of the Jedi to depict Yoda's death and is featured in a deleted scene from Revenge of the Sith showing Yoda's arrival on the planet. George Lucas reportedly said it was removed so the film would not have "too many endings." The scene was released under the title "Exile to Dagobah" on the film's DVD.

Other media
The Clone Wars featured Dagobah in a sixth-season episode, in which Yoda traveled to the planet as part of his own training to gain immortality through the Force.

In the Star Wars expanded universe, Yoda confronted a Bpfasshi Dark Jedi on Dagobah, some years before the events in The Empire Strikes Back, and the cave where the Dark Jedi died became strong in the dark side of the Force. Star Wars Tales later retconned this event to take place earlier, with another Jedi of Yoda's species named Minch replacing Yoda. Dagobah was also visited by the main characters of the Galaxy of Fear series, where it was home for a time to a tribe of cannibals. During the events of Jedi Knight: Jedi Academy, a team of Jedi Knights from the New Jedi Order visit Dagobah, to find the cave drained of its former menace.

After the events of Return of the Jedi, the New Republic founded a military base on one of the greatest mountains of the planet, named 'Mount Yoda' after the Jedi Master.

Description
Largely looked over by the Galactic Republic, Dagobah is the only habitable planet in the system of the same name within the Sluis sector. A cloudy and swampy world of dense foliage, countless living things of all sizes, including reptiles, amphibians, and swarming insects, fill its environs with a hum of constant noise. All of its creatures appear completely unintelligent. Larger life-forms occupy cave-like hollows formed by petrified forests. Carnivorous "gnarltrees" reproduce as spiderlike mobile creatures which eventually metamorphose into their rooted form. The planet is also noted for being strong with the Force.

Analysis
Several scholars have interpreted Dagobah as the station of initiation when applying Joseph Campbell's schema of the hero's journey, going back to ancient myths, to the character of Luke Skywalker: the hero retreats "from society to a world of more primal symbols where he must conquer his own darkness and return to the social world with a new redemptive knowledge." Dagobah is described as "like something out of a dream" and corresponds to "a spiritual plane". This primordial and isolated place of power, which seems hostile to civilization - the technological R2-D2 "is spat out unceremoniously" - is "a sanctuary of nature" and "creates a space, which like no other, influences the conception and development of the hero". Leah Deyneka linked the teeming nature of Dagobah with the "enchanted forest or sacred grove" which "figures frequently in fairy tales and myths; trees are believed to hold special powers and forests symbolize mastery and transformation." Miles Booy saw Dagobah as a "richly constructed [...] semiotic environment" which "does not point towards prior films but to widely circulated discourses concerning human consciousness". Its jungle and "dark swamp infested by reptiles" may be considered an image of the subconscious, with Yoda fulfilling the role of the analyst who "raises to the surface" what has been submerged.

Dan Catalano commented that Dagobah as "an eerie location filled with strange wildlife and shrouded in as much mystery as fog", removed from the technology-filled galaxy, is a fitting device to underline Yoda's status as a "Wise Man archetype" in the tradition of Merlin, who likewise can be found in places of "wild nature" in Arthurian myths.

Booy commented that within Star Wars "[n]o other environment attempts such imagery as Dagobah is constructed of" and that "Dagobah would also come to be the basis for [...] the notion that the film constitutes a form of mythology."

title: Dagobah


text:
Royal Swinkels

Royal Swinkels (formerly Swinkels Family Brewers and Bavaria Brewery) is a family business from North Brabant in the Netherlands, that is active in the beer, soft drink and malt sector. The company is fully owned by the Swinkels family for seven generations. The head office is located in Lieshout.

Swinkels Family Brewers is the second largest brewery company in the Netherlands after Heineken and one of the largest producers of malt in Europe. The business has a turnover of more than 1128 million euros per year. The company is commercially active in more than 150 countries. Two-thirds of the turnover is achieved in Europe. The focus is in Western Europe with more than half of the turnover. Outside of the European market, the largest contribution comes from the Middle East/Africa region, where a total of twenty percent of turnover is achieved.

Products
Royal Swinkels produces and markets beer, malt and soft drinks.

Beer
The business operates eight brewery locations: three in the Netherlands, three in Belgium, one in Ethiopia and one in Cuba. These breweries produced nearly 7 million hectolitres of beer in 2023. The group sells beer under several brand names, including Bavaria, Swinckels', La Trappe and Rodenbach.

About 12 percent of the total beer production consists of alcohol-free and low-alcoholic beer (less than 3.5%).

Malt
Swinkels Family Brewers owns two malt houses, one in Lieshout and one in Eemshaven. The annual capacity totals 400,000 tons of malt, a third of which is used by Swinkels Family Brewers itself. One third of the production is sold to third parties in Europe and one third goes to countries outside Europe, mainly to Latin America, South America and Japan. Sales of malt contribute to around fifteen percent of Swinkels Family Brewers sales.

Soft drinks
The company produces approximately 626,000 hectoliters of soft drinks per annum, of which almost 95 percent as private label products. Swinkels Family Brewers itself uses the brand names 3ES and B52. Negus, a non-alcoholic, coffee-flavoured malt drink is brewed in Ethiopia.

Local brewery
The history of Swinkels Family Brewers can be traced back to 1680. In that year Dirk Vereijken owned a brewery at the Kerkdijk (Church Dike Road) in Lieshout, proof of which can be found in an account of the municipal tax records of that year. This brewery was transferred from father to daughter for three consecutive generations. The names of the new brewing families were Van Moorsel and Moorrees. In 1764 Brigitta Moorrees married Ambrosius Swinkels. After her mother's death in 1773, Brigitta and her husband became the full owners of the brewery. Since then, the brewery has been owned by the Swinkels family.

Regional brewery
For centuries the brewery only produced beer for the local market. It was not until the fourth generation of Swinkels took charge of the brewery that production was expanded. Jan Swinkels, born in 1851, started distribution to the city of Helmond at 10 km from Lieshout in 1890. Sales rose from 988 hectolitres of beer in 1890 to 1,900 hectolitres in 1900. After the First World War distribution was expanded to other towns and villages in North Brabant. By 1923 output had increased to 3,325 hectolitres of beer. By that time the original brewery buildings had become too small so a larger brewery was built in Lieshout. On that occasion three brothers of the fifth generation of Swinkels took over leadership, and adopted the brand name Bavaria. This name indicated that the new plant was a bottom fermentation brewery, producing pale lager (Bavarian) beer.

Nationwide distribution
Distribution was broadened to include Amsterdam, Rotterdam, The Hague and Utrecht, the four largest cities of the Netherlands. In 1933 the brewery added its own bottling plant, which produced 2,000 bottles an hour. By 1940 a malt house was built. The output of the brewery at the beginning of the Second World War was approximately 40,000 hectolitres per annum, with an almost nationwide coverage in distribution.

In 1955 the company started manufacturing soft drinks under the brand name 3-ES. This name refers to the three Swinkels brothers of the fifth generation. In the postwar years beer consumption in the Netherlands had decreased to a very low level. It took the firm until 1959 to recover in terms of sales volume. In the sixties the company doubled its production capacity.

World player
From 1973 onwards the company took an interest in the exporting business, first of all in Southern Europe. In the late seventies the firm introduced alcohol-free beer, that was exported to Islamic countries. By 1981 the total volume reached 1,000,000 hectolitres of beer. From the nineties onwards the business expanded into exclusive and seasonal beers. Moreover, the company started to adapt its drinks to individual markets. Consequently, export grew to cover 130 countries.

In 1999, the Trappist Koningshoeven Abbey, located in Berkel-Enschot, entered into an agreement with the Swinkels family to take over the daily operations of the monks' brewery within the abbey. The brewery, which operates as "De Koningshoeven NV", is a subsidiary of Swinkels Family Brewers, whilst the buildings and equipment remain in the ownership of the abbey. The monks remain the ultimate authority on the brewing process while Swinkels Family Brewers manages the commercial business. The beer is sold under the brandname La Trappe.

On 10 May 2016 it was announced that the company N.V. has taken a majority stake in the Belgian brewery Palm. Initially the firm acquired 60% of the shares and this was expanded to 100% in 2021. In November 2016 the company acquired Latis Imports, establishing a dedicated US presence in one of its "five key regions".

In June 2018 it was decided to change the name of Bavaria to Swinkels Family Brewers. In March 2019, Wim van de Donk, Commissioner of the King of the province of Brabant, announced that Swinkels Family Brewers would from now on have the Royal predicate, officially naming the company 'Royal Swinkels Family Brewers'. It has been gained for the 300th anniversary of the company and their national significance. As from 2024 the name was shortened to Royal Swinkels.

Price fixing conviction
On 18 April 2007 the European Commission imposed punitive fines on three major European breweries for operating a price fixing cartel in the Netherlands. The three were Heineken (€219.3m), Grolsch (€31.65m) and Swinkels Family Brewers (€22.85m). A fourth participant in the cartel, InBev (formerly Interbrew), did not receive a penalty because it provided "decisive information" about the cartel's operations between 1996 and 1999, as well as about others in the European Union. These four brewers had control of 95% of the Dutch market, with Heineken claiming a half and the three others 15% each.

EU Competition Commissioner Neelie Kroes said she was "very disappointed" that the collusion took place at the very highest (boardroom) level. She stated, "This is simply unacceptable: that major beer suppliers colluded to up prices and to carve up markets among themselves. She added, "Heineken, Grolsch, Bavaria and InBev tried to cover their tracks by using code names and abbreviations for secret meetings to carve up the market for beer sold to supermarkets, hotels, restaurants and cafes. The price fixing extended to cheaper own-brand labels and rebates for bars.

World Cup Ambush Marketing campaigns
At the 2006 FIFA World Cup, Swinkels Family Brewers got up to 1,000 fans of the Netherlands national football team to don orange overalls, called Leeuwenhosen, with the brewery's logo on them. The Leeuwenhosen were given away with the purchase of Swinkels Family Brewers products prior to the World Cup. However the action was deemed to be an act of ambush marketing by FIFA as Swinkels Family Brewers, which was not a corporate sponsor, had not paid any money to be an official event partner. With pre-warning from FIFA officials, staff at the game versus Ivory Coast asked fans to remove the overalls upon entrance to the game and provided orange replacement shorts without any logo.

During the 2010 FIFA World Cup, 36 women clad in orange miniskirts went to the Netherlands vs Denmark match in Johannesburg, using tickets supplied at least in part by British ITV pundit and ex-footballer Robbie Earle. Tournament officials evicted the group en masse from the stadium upon which they were arrested and held by the Police. They were released upon talks between the management of Swinkels Family Brewers and FIFA.

Publication

 * Antoon Swinkels & Peter Zwaal: Bavaria: a biography of the brewery in Lieshout and the family that owns it (Lieshout: Bavaria, 2008). ISBN 978-0-9731100-3-6

title: Royal Swinkels


text:
Nanotech (anthology)

Nanotech is a 1998 anthology of science fiction short stories revolving around nanotechnology and its effects. It is edited by American writers Jack Dann and Gardner Dozois.

Contents

 * "Blood Music" by Greg Bear
 * "Margin of Error" by Nancy Kress
 * "Axiomatic" by Greg Egan
 * "Remember'd Kisses" by Michael F. Flynn
 * "Recording Angel" by Ian McDonald
 * "Sunflowers" by Kathleen Ann Goonan
 * "The Logic Pool" Stephen Baxter
 * "Any Major Dude" Paul Di Filippo
 * "We Were Out of Our Minds with Joy" by David Marusek
 * "Willy in the Nano-lab" by Geoffrey A. Landis

title: Nanotech (anthology)


text:
Eskimo bowline

The Eskimo bowline, Cossack knot (Казачий узел), reverse bowline, or 'anti-bowline' is in a class of knots known as 'eye knots' or 'loop knots'. The eye is formed in the end of the rope to permit attachments/connections. It is quite common in Russia and is often used instead of the bowline (ABoK #1010). In the simple bowline, the collar component forms around the 'standing part'. In contrast, the collar component of an Eskimo bowline forms around the outgoing eye-leg.

On the first of arctic explorer John Ross' expeditions (1818) the Inuit (Eskimos) presented him a sled that contained several of these knots, showing that it is a genuine Inuit knot. The knot is not mentioned in The Ashley Book of Knots but in its Russian equivalent, the book "Морские узлы" (Marine Knots) by Lev Skryagin (1930–2000). The slipped version is known as Kalmyk loop.

The Eskimo bowline is about as strong as and even more secure than the bowline, especially in synthetic lines.

Under cross load (ring loading, transverse loading profile), i.e. when the loop is pulled apart, the shown common Eskimo loop effectively mimics an ends-opposite (and inferior) left-hand sheet bend and thus can slip like the bowline; the less common Eskimo loop variant with the A–C loop (see bowline family diagram) would give a proper same-side sheet bend, thus being much stronger under cross load. Similarly, when the eye of a simple Bowline is subject to a transverse loading profile, it mimics the inferior version of the Lapp bend, and so can slip and untie; the wrongly demeaned left-handed or cowboy bowline becomes the proper Lapp bend, and should hold..

All of the maneuvers to tie this knot are generally in the opposite (or 'anti' direction) relative to the bowline. After forming the 'nipping loop' with C & D (which can be formed as 'S' or 'Z' chirality) the working end is fed through that loop from the same side A as the outgoing eye leg C. This is opposite (or 'anti') direction relative to the simple (#1010) Bowline (A–D on opposite sides).

The so called 'Eskimo' Bowline has also been known as Boas Bowline and Cossack knot - all of these names referring to the same structure. The Kalmyk loop can be made 'TIB' (Tiable In the Bight); however, it will not be 'EEL' (Either End Loadable).

title: Eskimo bowline


text:
Beonex Communicator

Beonex Communicator is a discontinued open-source Internet suite based on the Mozilla Application Suite (MAS) by Ben Bucksch, a German Mozilla developer. It was intended to have a higher security and privacy level than other commercial products. The Internet suite contains a Web browser, an email and news client, an HTML editor (based on Mozilla Composer) and an IRC client (based on ChatZilla).

Beonex Business Services offered the suite for free and provided documentation, easy install routines for third-party plug-ins, and tried to sell support and customer-specific changes on the browser. The main goal was to implement Kerberos, OpenPGP, and LDAP in Beonex, but that was marked as failed in mid-2004. It was discontinued before reaching production release stage.

History
Mozilla Organization stated that the Mozilla Application Suite was only for developers and testing purposes and was not meant for end users.

On 5 January 2001 Beonex was included in the Linux distribution kmLinux version S-0.4, but was removed in version S-0.5 released on 23 March 2001. Beonex 0.8 was released in June 2002 received positive reviews about its speed.

Beonex Launcher (BeOL, spoken B-O-L), was an additional upcoming product that never left alpha status; it was a stripped-down version of Beonex Communicator: a Web browser combined with an email client and a chat client.

With a few preview releases of version 0.9 in mid-2002, Bucksch showed some new features he wanted to integrate, but before this version gained a stable status, he announced on 2 March 2004 that no new releases were planned until the Mozilla Foundation decided its future policy. In 2005, the Mozilla Foundation officially changed its policies and created the Mozilla Corporation to provide end-user support.

Beonex Communicator 0.8.2-stable has several known security issues. Beonex never received much market share.

In October 2020, the distributor of Beonex joined the Coalition for App Fairness, which defends the rights of app developers.

Comparison with Netscape and MAS
The browser does not transmit referrers by default and has the possibility to create a fake referrers. The browser deletes all cookies upon exiting and disables several JavaScript functions which could have served as attack vectors. Beonex also allows changing the user agent.

In the following comparison table not all releases of Netscape and MAS are included. For a more complete table see Gecko (layout engine).

Differences from Netscape
In contrast with Netscape, Beonex has included nearly the same features except the proprietary parts like the integrated Net2Phone, and the AOL Instant Messenger. For online chatting, ChatZilla was integrated and the sidebar and the search engines are also pre-configured. Beonex is less resource-intensive than Netscape.

Beonex includes a migration tool to import old profiles from Netscape Communicator.

Differences from MAS
Beonex Communicator was not a fork of MAS; rather, it was a separate branch, so no significant changes were made. HTML email and JavaScript are turned off by default and thus, it displays email only in plain text with bold and cursive additions which were added later in MAS 1.1. The search engines is compatible with the Mycroft project and is located in the sidebar providing more features.

title: Beonex Communicator


text:
Land use

Land use involves the management and modification of natural environment or wilderness into built environment such as settlements and semi-natural habitats such as arable fields, pastures, and managed woods. Land use by humans has a long history, first emerging more than 10,000 years ago. It has been defined as "the purposes and activities through which people interact with land and terrestrial ecosystems" and as "the total of arrangements, activities, and inputs that people undertake in a certain land type." Land use is one of the most important drivers of global environmental change.

History
Human tribes since prehistory have segregated land into territories to control the use of land. Today, the total arable land is 10.7% of the land surface, with 1.3% being permanent cropland.

Regulation

Land use practices vary considerably across the world. The United Nations' Food and Agriculture Organization Water Development Division explains that "Land use concerns the products and/or benefits obtained from use of the land as well as the land management actions (activities) carried out by humans to produce those products and benefits." As of the early 1990s, about 13% of the Earth was considered arable land, with 26% in pasture, 32% forests and woodland, and 1.5% urban areas. Land change modeling can be used to predict and assess future shifts in land use.

As Albert Guttenberg (1959) wrote many years ago, Land use' is a key term in the language of city planning." Commonly, political jurisdictions will undertake land-use planning and regulate the use of land in an attempt to avoid land-use conflicts. Land use plans are implemented through land division and use ordinances and regulations, such as zoning regulations. Management consulting firms and non-governmental organizations will frequently seek to influence these regulations before they are codified.

United States

In colonial America, few regulations were originally put into place regarding the usage of land. As society shifted from rural to urban, public land regulation became important, especially to city governments trying to control industry, commerce, and housing within their boundaries. The first zoning ordinance was passed in New York City in 1916, and, by the 1930s, most states had adopted zoning laws. In the 1970s, concerns about the environment and historic preservation led to further regulation.

Today, federal, state, and local governments regulate growth and development through statutory law. The majority of controls on land, however, stem from the actions of private developers and individuals. Three typical situations bringing such private entities into the court system are: suits brought by one neighbor against another; suits brought by a public official against a neighboring landowner on behalf of the public; and suits involving individuals who share ownership of a particular parcel of land. In these situations, judicial decisions and enforcement of private land-use arrangements can reinforce public regulation, and achieve forms and levels of control that regulatory zoning cannot. There is growing concern that land use regulation is a direct cause of housing segregation in the United States today.

Two major federal laws passed in the 1960s limit the use of land significantly. These are the National Historic Preservation Act of 1966 (today embodied in 16 U.S.C. 461 et seq.) and the National Environmental Policy Act of 1969 (42 U.S.C. 4321 et seq.).

The US Department of Agriculture has identified six major types of land use in the US. Acreage statistics for each type of land use in the contiguous 48 states in 2017 were as follows:
 * Special use areas include national parks (29 M acres) and state parks (15 M), wildlife areas (64.4 M), highways (21 M), railroads (3M), military bases (25 M), airports (3M) and a few others. Miscellaneous includes cemeteries, golf courses, marshes, deserts, and other areas of "low economic value". ** The total land area of the US is 9.1 M km2 but the total used here refers only to the contiguous 48 states, without Alaska etc.

Urban growth boundary
The urban growth boundary is one form of land-use regulation. For example, Portland, Oregon is required to have an urban growth boundary which contains at least 20000 acre of vacant land. Additionally, Oregon restricts the development of farmland. The regulations are controversial, but an economic analysis concluded that farmland appreciated similarly to the other land.

Environment
Land use and land management practices have a major impact on natural resources including water, soil, nutrients, plants and animals. Land use information can be used to develop solutions for natural resource management issues such as salinity and water quality. For instance, water bodies in a region that has been deforested or having erosion will have different water quality than those in areas that are forested. Forest gardening, a plant-based food production system, is believed to be the oldest form of land use in the world.

The major effect of land use on land cover since 1750 has been deforestation of temperate regions. More recent significant effects of land use include urban sprawl, soil erosion, soil degradation, salinization, and desertification. Land-use change, together with use of fossil fuels, are the major anthropogenic sources of carbon dioxide, a dominant greenhouse gas.

According to a report by the United Nations' Food and Agriculture Organization, land degradation has been exacerbated where there has been an absence of any land use planning, or of its orderly execution, or the existence of financial or legal incentives that have led to the wrong land use decisions, or one-sided central planning leading to over-utilization of the land resources - for instance for immediate production at all costs. As a consequence the result has often been misery for large segments of the local population and destruction of valuable habitats and ecosystems.

title: Land use


text:
Douglas County, Colorado

Douglas County is a county located in the U.S. state of Colorado. As of the 2020 Census, the population was 357,978. The county is named in honor of U.S. Senator Stephen A. Douglas. The county seat is Castle Rock.

Douglas County is part of the Denver–Aurora–Lakewood metropolitan statistical area. It is located midway between Colorado's two largest cities, Denver and Colorado Springs, and contains a portion of Aurora, the state's third-largest city. Douglas County has the highest median household income of any Colorado county or statistical equivalent. It is ranked seventh nationally in that category.

Overview
Douglas County is lightly wooded, mostly with ponderosa pine, with broken terrain characterized by mesas, foothills, and small streams. Cherry Creek and Plum Creek rise in Douglas County and flow north toward Denver and into the South Platte River. Both were subject to flash flooding in the past, Plum Creek being partially responsible for the Denver flood of 1965. Cherry Creek and Plum Creek are now dammed.

Most residents commute to workplaces elsewhere in the metropolitan area outside of the county. Suburban development is supplementing the traditional ranching economy of the county.

History
Douglas County was one of the original 17 counties created in the Colorado Territory by the Colorado Territorial Legislature on November 1, 1861. The county was named in honor of U.S. Senator Stephen A. Douglas of Illinois, who died five months before the county was created. The county seat was originally Franktown, but was moved to California Ranch in 1863, and then to Castle Rock in 1874. Although the county's boundaries originally extended eastward to the Kansas state border, in 1874, most of the eastern portion of the county became part of Elbert County.

Geography
According to the U.S. Census Bureau, the county has a total area of 844 sqmi, of which 841 sqmi are land and 2.6 sqmi (0.3%) are covered by water.

Adjacent counties

 * Jefferson County, Colorado – west
 * Arapahoe County, Colorado – north
 * Elbert County, Colorado – east
 * El Paso County, Colorado – south
 * Teller County, Colorado – southwest

Major highways

 * I-25 (CO).svg Interstate 25
 * US 85.svg U.S. Highway 85
 * US 87.svg U.S. Highway 87
 * Colorado 67.svg State Highway 67
 * Colorado 83.svg State Highway 83
 * Colorado 86.svg State Highway 86
 * Colorado 105.svg State Highway 105
 * Colorado 121.svg State Highway 121
 * Colorado 470.svg State Highway 470
 * E-470.svg E-470 tollway

Parks and recreational areas
Three state parks fall within Douglas County: Castlewood Canyon State Park, Chatfield State Park and Roxborough State Park. Parts of the county lie within the Pike National Forest and were crossed by the historic South Platte Trail.

Recreation trails in the county include:
 * American Discovery Trail
 * Colorado Trail
 * Devils Head National Recreation Trail
 * Highline Canal National Recreation Trail
 * Platte River Greenway National Recreation Trail
 * Ridgeline Open Space Trail
 * Bluffs Regional Park Trail

The Rueter–Hess Reservoir, when filled, may provide significant recreation, including fishing, hiking, and nonmotorized boating. If filled to capacity, surface size would be 1,140 acres, making this a fairly significant reservoir in Colorado and Douglas County's largest body of water.

Cherokee Ranch and Castle is a 3,400-acre privately owned property which forms a 12,000-acre open space with the Highlands Ranch Backcountry and Daniels Park. The area is host to a variety of animals and the Cherokee Ranch petrified forest.

The Prairie Canyon Ranch, at 4620 CO-83, about 10 mi south of Franktown, is a Douglas County Open Space. It is a working cattle ranch on 978 acre, open to the public on special events.

Demographics
As of the census of 2000, 175,766 people, 60,924 households, and 49,835 families were residing in the county. The population density was 209 /mi2. The 63,333 housing units averaged 75 /mi2. The racial makeup of the county was 92.77% White, 2.51% Asian, 0.95% African American, 0.41% Native American, 1.49% from other races, and 1.88% from two or more races. Hispanics or Latinos of any race made up 5.06% of the population.

Of the 60,924 households, 47.2% had children under the age of 18 living with them, 73.8% were married couples living together, 5.7% had a female householder with no husband present, and 18.2% were not families. About 13.3% of all households were made up of individuals, and 1.9% had someone living alone who was 65 years of age or older. The average household size was 2.88, and the average family size was 3.19.

In the county, the population distribution was 31.6% under the age of 18, 4.8% from 18 to 24, 37.9% from 25 to 44, 21.6% from 45 to 64, and 4.2% who were 65 years of age or older. The median age was 34 years. For every 100 females, there were 99.7 males. For every 100 females age 18 and over, there were 97.4 males.

The median income for a household in the county was $82,929, and for a family was $88,482 (these figures had risen to $93,819 and $102,767, respectively, as of a 2007 estimate ). Males had a median income of $60,729 versus $38,965 for females. The per capita income for the county was $34,848. About 1.6% of families and 2.1% of the population were below the poverty line, including 1.9% of those under age 18 and 3.7% of those age 65 or over.

Douglas County had the highest median household income of any Colorado county or statistical equivalent in 2000. In 2008, it ranked eighth in the United States in that category; it was one of two in the top 15 not in the vicinity of New York or Washington.

Health and longevity
In 2021, Douglas County was judged by the U.S. News & World Report to be the second healthiest of 3,143 counties and county-equivalents of the United States based on 84 different factors. Residents of the county lived 84.0 years on the average compared to the U.S. average of 77.5 years.

Politics
As a primarily exurban county, Douglas County has long been known as a Republican stronghold. In the 2012 election, Mitt Romney won 62% of the vote. Douglas County has become more competitive in recent years due to voters leaving the Republican Party, with Donald Trump winning 55% of the county's vote in 2016, and only 52% of the vote in 2020. Joe Biden, meanwhile achieved the highest vote share for a Democratic presidential nominee in the county since 1964. In 2022, incumbent Democratic governor Jared Polis lost the county by a razor-thin margin, winning nearly 49% of the vote. However, Democratic strength is mostly limited to northern Douglas County, including Highlands Ranch, Lone Tree, and Meridian, while the rest of the county is still strongly Republican.

Education
Douglas County is served by Douglas County School District RE-1, the third-largest school district in Colorado. In addition to traditional neighborhood schools, the district includes sixteen charter schools, four option schools, and an online school. Schools are rated generally high in the area.

The University Center at Chaparral in Parker offers courses through Arapahoe Community College, the University of Colorado Denver, University College of the University of Denver, and the Douglas County School District. The University of Phoenix has a campus in Lone Tree.

The county was home to its own university, the University of Colorado South Denver in Lone Tree, but it permanently closed in 2021 due to the COVID-19 pandemic and financial concerns.

Libraries
The Douglas County Libraries system has seven branches throughout the county. The library also houses the Douglas County History Research Center, which collects and preserves the history of Douglas County, the High Plains, the Divide area of the Front Range and the State of Colorado, to provide historical research resources to the public.

Top employers

According to the county's 2015 Comprehensive Annual Financial Report, the top employers in the county are:

Recognition
Douglas County has been recognized by a number of national periodicals:
 * Money magazine ranked Douglas County number five in the United States for “Job Growth over the Last Eight Years”, August 18, 2009
 * American City Business Journals (ACBJ) ranked Douglas County fourth in the nation for “Quality of Life”, May 2004
 * SchoolDigger.com ranked Douglas County School District at number one in the Denver metropolitan area and number 12 in Colorado based on 2009 test scores. (School district rankings were determined by averaging the rankings of individual schools within each of the 122 districts evaluated.)

Cities

 * Aurora (part)
 * Castle Pines
 * Littleton (part)
 * Lone Tree

Towns

 * Castle Rock
 * Larkspur
 * Parker

Census-designated places

 * Acres Green
 * Castle Pines Village
 * Franktown
 * Grand View Estates
 * Highlands Ranch
 * Louviers
 * Meridian
 * Meridian Village
 * Perry Park
 * Roxborough Park
 * Sedalia
 * Sierra Ridge
 * Stepping Stone
 * Sterling Ranch
 * Stonegate
 * The Pinery
 * Westcreek

Other unincorporated communities

 * Dakan
 * Deckers
 * Greenland

Former census-designated places

 * Carriage Club (now part of Lone Tree)
 * Cottonwood (now part of Parker)
 * Heritage Hills (now part of Lone Tree)

title: Douglas County, Colorado


text:
Castle Rock, Colorado

Castle Rock is a home rule town that is the county seat and the most populous municipality of Douglas County, Colorado, United States. The town population was 73,158 at the 2020 census, a 51.68% increase since the 2010 census. Castle Rock is the most populous Colorado town (rather than city) and the 16th most populous Colorado municipality. Castle Rock is a part of the Denver-Aurora-Lakewood, CO Metropolitan Statistical Area and the Front Range urban corridor.

The town is named for the prominent, castle-shaped butte near the center of town.

History
The region in and around Castle Rock was originally home to the Arapaho and Cheyenne peoples. They occupied the land between the Arkansas and South Platte Rivers.

White settlers were drawn to the area by rumors of gold and by land opened through the Homestead Act of 1862. However, the discovery of rhyolite stone, not gold, ultimately led to the settlement of Castle Rock.

Castle Rock was founded in 1874 when the eastern Douglas County border was redrawn to its present location. Castle Rock was chosen as the county seat because of its central location.

One of the first homesteaders in the area near today's Castle Rock was Jeremiah Gould. He owned about 160 acre to the south of "the (Castle) Rock." At that time, the settlement consisted of just a few buildings for prospectors, workers, and cowboys. In 1874, Gould donated 120 acre to the new town, which was also now home to the Douglas County government. Six streets named Elbert, Jerry, Wilcox, Perry, Castle, and Front were laid out to build the actual town of Castle Rock. The courthouse square was defined and about 77 lots, each 50 by 112 ft, were auctioned off for a total profit of US$3,400.

A new train depot brought the Denver and Rio Grande Railway to the area.

During the late 1800s and early 1900s, Castle Rock had a very active rhyolite quarrying industry. Many immigrants arrived in the area to work in the quarries.

In 1936, the town received a donation of land that included its namesake geographical feature. Men employed by the Works Progress Administration constructed a star atop the butte shortly after Castle Rock received that donation. The star was lit every year from 1936 to 1941. After World War II began, the star was left unlit as a symbol of sacrifice in support of the war effort. On August 14, 1945, shortly after V-J Day, the star was modified into a V-for-victory symbol. On December 7, 1945, the star was lit for the holiday season. It has been lit every year since around the same time.

The town's historic county courthouse, which was built in 1889–1890, burned down on March 11, 1978, the result of arson.

Castle Rock's municipal government experienced significant financial difficulties during the early 1980s. In 1984, the town's voters approved a charter amendment that authorized the creation of a home-rule charter commission. The home-rule charter was finalized in 1987.

The original Douglas County courthouse was one of seven buildings in Castle Rock that have been added to the National Register of Historic Places. The other buildings include Castle Rock Depot, Castle Rock Elementary School, First National Bank of Douglas County, Samuel Dyer House, Benjamin Hammer House, and Keystone Hotel.

A dispute about whether the Castle Rock Police Department was required to enforce a civil restraining order was decided by the U.S. Supreme Court in 2005. The court held, in Town of Castle Rock v. Gonzales, that a municipality cannot be held liable under a federal civil-rights statute, 42 U.S.C. § 1983, for failing to enforce civil restraining orders. The case had arisen from a 1999 murder of three young girls by their father outside the Castle Rock Police Department building. The children were abducted by their father, in violation of the restraining order that had been obtained by their mother, within several hours of being killed. The mother had asked the Castle Rock police to enforce the restraining order by finding and apprehending the father after he removed the children from her home and before the murders. Castle Rock police officers declined to do so, refusing even to contact the Denver Police Department after the mother notified them that the father had taken the children to an amusement park in that city.

Geography
Castle Rock is located at 39.37222°N, -104.85611°W (39.372212, −104.856090) at an elevation of 6,224 feet (1,897 m). Castle Rock is in central Colorado at the junction of Interstate 25 and State Highway 86, 28 mi south of downtown Denver and 37 mi north of Colorado Springs.

The town lies a few miles east of the Rampart Range of the Rocky Mountains on the western edge of the Great Plains. Castle Rock, the butte for which the town is named, is just north of the town center. Other prominent landforms visible from Castle Rock include Dawson Butte, Devils Head, Mount Blue Sky, and Pikes Peak.

East Plum Creek, a stream within the South Platte River watershed, flows generally north through Castle Rock. Hangman's Gulch, which runs northwest then west around the north side of the town center, drains into East Plum Creek, as do multiple unnamed gulches in the southern and western areas of town. McMurdo Gulch and Mitchell Gulch run north then northeast through eastern Castle Rock and drain into Cherry Creek east of town.

Castle Rock is in the Colorado Foothills Life Zone. The hillsides are covered with meadows of grass, small plants, scattered juniper trees and open ponderosa pine woodlands. Other trees common in the area include Gambel oak (scrub oak or oak brush) and pinyon pine. Local wildlife includes the American badger, American black bear, bobcat, coyote, Colorado chipmunk, crow, garter snakes, gray fox, mountain cottontail rabbit, mountain lion, mule deer, pocket gopher, porcupine, skunk, and tadpoles. Birds found in the area include the golden eagle, peregrine falcon, sharp-shinned hawk, black-billed magpie, red-tailed hawk, pinyon jay, and western tanager.

The town had a total area of 89.981 km2, all land in 2023.

Lying within the Front Range urban corridor, the town is part of the greater Denver metropolitan area. Castle Rock borders three communities, all to its north; from west to east, they are Castle Pines Village, the city of Castle Pines, and The Pinery. Other nearby communities include Franktown to the east, Larkspur to the south, Perry Park to the southwest, and Sedalia to the northwest.

Climate
Castle Rock has a semiarid climate (Köppen BSk) with cold, dry, snowy winters, and hot, wetter summers. January is the coldest month, July the hottest, and August the month with the most precipitation.

Statewide, Colorado has experienced an average temperature increase of about 2.5 F-change over the past half-century. Given its location in the center of the state, it is expected that Castle Rock will experience continuing warming and higher average temperatures through the 21st century as the effects of climate change continue to be felt. Daily minimum temperatures are also expected to continue rising, as they have for the past 30 years.

Neighborhoods
Castle Rock's ZIP codes include many neighborhoods:

North of Downtown / West of I-25
 * The Meadows
 * Castle Pines Village

Castle Rock encompasses about 35 sqmi, with a population of more than 73,000.

2010 census
As of the 2010 census, there were 48,231 people, 16,688 households, and 12,974 families residing in the town. The population density was 1,526.3 PD/sqmi. There were 17,626 housing units at an average density of 557.8 /sqmi. The racial makeup of the town was 90.7% White, 1.7% Asian, 1.1% African American, 0.6% American Indian, 0.1% Pacific Islander, 2.9% from other races, and 2.8% from two or more races. Hispanics and Latinos of any race were 10.0% of the population.

There were 16,688 households, out of which 48.4% had children under the age of 18 living with them, 65.4% were married couples living together, 3.9% had a male householder with no wife present, 8.5% had a female householder with no husband present, and 22.3% were non-families. 17.7% of all households were made up of individuals, and 4.0% had someone living alone who was 65 years of age or older. The average household size was 2.86, and the average family size was 3.27.

In the town, the population was spread out, with 32.4% under the age of 18, 5.8% from 18 to 24, 33.0% from 25 to 44, 22.6% from 45 to 64, and 6.2% who were 65 years of age or older. The median age was 33.8 years. For every 100 females, there were 98.5 males. For every 100 females age 18 and over, there were 95.5 males age 18 and over.

The median income for a household in the town was $85,461, and the median income for a family was $95,973. Males had a median income of $66,993 versus $47,087 for females. The per capita income for the town was $34,089. About 4.0% of families and 6.2% of the population were below the poverty line, including 8.2% of those under age 18 and 6.2% of those age 65 or over.

Castle Rock is the 16th most populous municipality in Colorado and is the center of the burgeoning urbanization of the county.

Economy
Because of its Front Range location between Denver and its inner suburbs and Colorado Springs, many of Castle Rock's residents commute nearly 20 miles to northern Colorado Springs or the Denver Technological Center, better known as "The Denver Tech Center" (DTC), which is an 18-mile drive north on I-25, with Downtown Denver roughly 30 miles north, and Denver International Airport about 45 miles north.

In fact, about 80% of Castle Rock residents commute out of town to work. The average one-way commute time for a Castle Rock resident is about 29 minutes, longer than the U.S. average.

One reason for this is that the town has not yet attracted the variety or extent of employers needed to significantly lower the number of commuters to work outside Castle Rock. The town has relatively little land zoned for industrial or light industrial use, with the vast majority of the land within town limits dedicated to residential construction only.

As of 2011, 78.2% of the population over the age of 16 was in the labor force, 0.4% was in the armed forces, and 77.7% were in the civilian labor force, with 72.6% employed and 5.1% unemployed. The employed civilian labor force was 48.0% in management, business, science, and arts; 25.8% in sales and office occupations; 14.7% in service occupations; 6.4% in natural resources, construction, and maintenance; and 5.2% in production, transportation, and material moving. The three industries employing the largest proportion of the working civilian labor force were educational services, health care, and social assistance (15.5%); professional, scientific, and management, and administrative and waste management services (13.2%); and finance and insurance, and real estate and rental and leasing (12.6%).

Castle Rock's cost of living is above average. Compared to a U.S. average of 100, the cost of living index for the town is 137.2.

As of mid-2019, the median home value in the town was $427,537. The median gross monthly rent for an apartment was about $1,461.

The town's housing base continues to grow. About 1,400 permits to build new homes were issued in 2018.

Government and politics
Castle Rock is a home rule municipality with a council–manager form of government. The Town's governing body is the Town Council, made up of seven members including the mayor and mayor pro-tem. Each councilmember is elected to represent an election district, and the mayor is elected to represent the Town at large. One member, appointed by the council, serves as the mayor pro-tem. Castle Rock voters approved a change to the town charter that authorized an at-large mayor in 2017.

The mayor presides over council meetings and casts one vote, like other councilmembers. The council sets policy for the town, adopts ordinances, approves the town budget, makes major land-use decisions, and appoints key town government staff including the town manager, town attorney, municipal judge, and members of town boards and commissions.

The town manager supervises all departments, prepares and implements the town budget, and works with the council to develop policies and propose new plans.

Tax revenues are used to provide general government, fire, police, parks maintenance and programs, street maintenance and operations, support for recreation, and planning and code enforcement services. The town also provides development services, golf, water, and sewer services to residents through self-supporting enterprise funds. The average annual municipal property tax bill of a Castle Rock resident is $40.66. That is in addition to property taxes assessed by Douglas County and other entities.

As the county seat, Castle Rock is the administrative center of Douglas County. The county courthouse, the Douglas County Justice Center, is north of downtown, and most departments of the county government base their operations in the town.

As of, Castle Rock lies within Colorado's 4th U.S. Congressional District. The town is in the 4th district of the Colorado Senate and the 45th district of the Colorado House of Representatives.

Castle Rock is the county seat of Douglas County, a Republican stronghold in Colorado.

Primary and secondary education
Douglas County School District is based in Castle Rock and operates 18 public schools in the town. These include ten elementary schools, two middle schools, two charter schools, one magnet school, one alternative high school, and two high schools: Castle View High School and Douglas County High School. In addition, there are three private primary schools in Castle Rock.

School board elections in Douglas County are held in odd-numbered years. In recent years the community has experienced a spirited debate between supporters of significant change in the management of local schools and those who oppose such changes or believe they should advance at a slower pace.

Libraries
The Douglas County Libraries public library system is based in Castle Rock, co-located with the local branch library, the Philip S. Miller Library, south of downtown. The Miller Library includes Archives and Local History and offers several educational and recreational programs to the public. Also, it includes Little Free Library places scattered throughout, such as in festival park.

Transportation
Interstate 25 and U.S. Route 87 run concurrently north-south through Castle Rock. U.S. Route 85, also a north-south route, enters the town from the northwest, meeting I-25 at Exit 184; south of the exit, it runs concurrently with I-25 and U.S. 87. Colorado State Highway 86, an east-west route, enters Castle Rock from the east, then turns north and west as Founders Parkway, terminating at its junction with I-25 at Exit 184.

For local transportation within Castle Rock, the town government sponsors a voucher program for reduced-fare taxi service. This service is available to town residents who are disabled or who do not have access to a vehicle. In addition, the Castle Rock Senior Center offers a shuttle service for resident senior citizens.

Castle Rock does not participate in the Denver metropolitan area's Regional Transportation District. Municipal voters decided in November 2005 to opt the town out of RTD. As a result, neither bus nor light rail service to Denver or any of its other suburbs is available from Castle Rock.

BNSF Railway and Union Pacific Railroad each have a freight rail line that runs through Castle Rock. Both lines run parallel to U.S. 85.

Utilities and water
The Intermountain Rural Electric Association, based in nearby Sedalia, provides electric power. Black Hills Energy provides natural gas service. Waste Management and other businesses provide trash removal.

The town government's Utilities Department oversees water provision, distribution, and infrastructure maintenance. Historically, nearly all of the water needed by Castle Rock residents was pumped from aquifers below the ground, including the Denver Basin aquifer. Beginning in 2013, when the town developed its first strategic plan for the management of water, Castle Rock has moved toward more use of surface water. Between 2006 and 2018 per capita water use in Castle Rock declined from 137 gallons to 115 gallons.

Starting in 2020, Castle Rock expects to begin treating sink, tap, and toilet water to drinkable water quality standards so that it can be reused. The town aims to achieve a goal of reliance upon renewable water resources for 75% of municipal needs by 2050 and, by 2020, about one-third of all water used in Castle Rock is expected to be from a reusable source.

As of July 2019 Castle Rock, Denver, and Pitkin County are the first three Colorado municipal or county governments to adopt a state regulation governing greywater reuse.

Health care
Castle Rock has several medical offices, an urgent care, and an emergency room. Castle Rock Adventist Hospital, a full-service hospital, opened on August 1, 2013. The 50-bed hospital offers comprehensive health care to the Douglas County area, with labor and delivery suites, NICU, orthopedic surgery, ICU, and medical imaging.

Media
Castle Rock has a weekly newspaper, The Douglas County News-Press.

Castle Rock is part of the Denver radio and television market. Radio station KJMN is licensed to Castle Rock, but broadcasts from Denver playing a Spanish Adult Hits format on 92.1 FM. Denver radio station 850 KOA, which broadcasts a news/talk and sports format, operates its 50,000 watt transmitter from a site 10 miles northeast of downtown Castle Rock, in the town of Parker. Another Denver station, KAMP (1430 AM), a CBS Sports Radio affiliate with a Sports Radio format, operates its transmitter from Highlands Ranch, 13 miles north of downtown Castle Rock.

NPR programming can be heard on Colorado Public Radio's KCFR-FM. Castle Rock is also served by the AM signal of KGNU, a non-commercial affiliate of PRI, Pacifica, and the BBC World Service, and which also provides diverse music programming.

Television station KETD, an affiliate of the Estrella TV network, broadcasts on digital channel 46. Licensed to Castle Rock, the station is located near Centennial, Colorado.

Parks and recreation
Castle Rock's open space and parks comprise 27% the town's total land area (5415 acre of parks and open space / 20224 acre total land area). Additionally, there are nearly 75 mi of soft-surface and paved trails.

Points of interest
Philip S. Miller Park is the largest park project in Castle Rock. "Phase One" of the park was opened to the public on October 25, 2014. It remains under construction. The park is named after a local banker and philanthropist who, with his wife, Jerry, left trust monies to Castle Rock in the mid-1990s. The Phillip S. Miller Activity Center is included in the park's 300 acres.

The Castle Rock Historical Museum is in the former Denver and Rio Grande Railway depot building on Elbert Street. This building is purported to have been built in 1875. It is made of rhyolite taken from local quarries. The museum depicts how Castle Rock has changed over the years.

Sports
From 1986 through 2006, a professional golf tournament was held in Castle Pines Village. The International, a PGA Tour event, was held in August at the Castle Pines Golf Club.

Castle Rock star lighting
Since 1936, every Saturday before Thanksgiving, the Town of Castle Rock lights the 45 ft electric star upon Castle Rock. A lighting event is held downtown that night and is usually accompanied by a fireworks display. The star remains lit from the week before Thanksgiving to the end of the National Western Stock Show in January. This has changed multiple times, following World War II it was changed to a V, also, the same year as the Denver Broncos being in the Super Bowl, it was changed to orange and blue. Throughout part of the lockdown in early 2020 due to COVID-19, the star was relit as a symbol of unity.

Notable people
Notable individuals who were born in or have lived in Castle Rock include:
 * Amy Adams (born 1974), actress
 * Kirsten Bomblies (born 1973), biologist
 * Kat Cammack - United States Representative for Florida's 3rd Congressional District
 * Jim Cottrell (born 1983), NFL linebacker
 * Gary Hallberg (born 1958), professional golfer
 * Beth Malone (born 1969), actress
 * Christian McCaffrey (born 1996), professional football player (running back)
 * Max McCaffrey (born 1994), professional football player (wide receiver)
 * Joe Oltmann, political activist and conspiracy theorist
 * Will Owen (born 1995), racing driver
 * Nelson Rangell (born 1960), jazz musician
 * Edward Seidensticker (1921–2007), Japanologist
 * Ann Strother (born 1983), WNBA player, coach
 * Ann Strother (born 1983), WNBA player, coach

title: Castle Rock, Colorado