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🔗 Computing

In laptop computing, the XJACK is a type of extendable connector or antenna for a type II PC card, designed by the Megahertz subsidiary of 3Com. When not in use, the XJACK retracts into the PC card for storage.

The XJACK was originally used in modem and network cards, to attach a standard RJ11 or 8P8C plug directly to the PC card. They do not require a separate dongle, which could be lost or misplaced, and do not need to be removed from the laptop when travelling. An alternative approach is to use larger type III cards with a regular modular connector socket, but this approach requires more space.

Wi-Fi PC cards for accessing wireless networks have an external portion containing the antenna for improved reception (as compared with inside the laptop), but this portion of the card may be accidentally damaged while moving the laptop. 3Com manufactured wireless cards with retractable antenna portions, also under the XJACK name. Other companies have since manufactured wireless cards with retractable antennas.

🔗 Telecommunications

The Wheatstone system was an automated telegraph system that replaced a human operator with machines capable of sending and recording Morse code at a consistent fast rate. The system included a perforator, which prepared punched paper tape called a Wheatstone slip, a transmitter that read the tape and converted the symbols into dots and dashes encoded as mark and space electric currents on the telegraph line, and a receiver at the other end of the telegraph line that printed the Morse symbols. The system was invented by Charles Wheatstone. Enhancements could be made so that it was a duplex system, able to send and receive on the same line simultaneously.

The Wheatstone slip was a paper tape that contained holes in a pattern to control the mark and space signals on the telegraph line. The paper tape was from 0.46 to 0.48 inches in width, (but the standard width is from 0.472 to 0.475 inches) and a standard thickness of 0.004 to 0.0045 inches. Olive oil coating lubricated the punch process. There were three rows of holes. The middle row forms a rack so that a star wheel can move the paper forward. Every used position on the tape has a middle hole punched. The top hole indicates when to turn on the mark signal on the line, and the bottom hole says to turn off the mark signal. Each vertical column represents a time interval in the Morse code, including the spacing between the holes. The holes are spaced 0.1 inches apart. A column of three holes turns on the mark at the beginning of the interval, and turns it off at the end making a dot. If there is a top hole without a bottom, and then the next column has a bottom without a top hole, mark is on for three intervals, and a dash is represented. If there is only a centre hole, then nothing changes, and this would normally be used to put in space between letters and words.

The Wheatstone perforator was a manually operated hole punch machine to produce Wheatstone slips. It had three buttons (or keys) labelled "A", "A1" and "A2". "A" punched the pattern for dot, "A1" punched the pattern for space, and "A2" punched the dash pattern in two columns. The keys were so difficult to press that fist-held rubber-tipped mallets were used to depress them and operate the punches. Using this, invalid combinations of holes could not be produced. The blank paper tape was fed in from the right over a roller and came out the left side. It was oriented in a vertical plane. The paper punches were labelled with numbers: 1 for the top hole of the dot, 2 for the sprocket hole for dot, and 3 for the bottom hole for dot. When a dash was punched, extra hole punches to the right punched a centre hole with number 4 and a bottom hole with number 5. The perforator was introduced in 1867. It enabled transmission speeds on a telegraph line to increase to 70 words per minute. The very first message ever punched onto a tape was "SOS EIOS". The manual perforator was subsequently replaced by keyboard perforators like the Gell keyboard perforator or Kleinschmidt keyboard perforator.

Each of the keys had a spring to restore its position after pressing. Each key moved a corresponding lever underneath the instrument. The other end of the levers protruded up into the back of the mechanism. Each punch rod also had a spring to put it back in place after punching a hole. For space and dot keying (A or A1) the star wheel was only allowed to turn one position by a pawl, and the paper tape only moved forward one position. However, when key A2 was hit, the corresponding lever B2 raised a bar (h) which allowed another lever attached to the pawl to move further back when the star wheel rotated, and the wheel could turn two positions, for a dash. The distance the paper tape moved for each position was determined by how far lever k moved, and its range of movement had to be set by adjusting screws i and t. A flat spring g stored energy from the punch to move the paper. The force of the spring was determined by adjusting screws n and n'. A guide roller (r) with a groove was pressed by an adjustable spring to press the pawl against the star wheel. The star wheel was on a frame with a piece sticking out the left hand side as a lever. When the operator wanted to insert paper tape, this lever was pulled, and the star wheel retracted from the paper.

The Wheatstone transmitter read a paper tape (Wheatstone slip) and converted the dot pattern into mark and space symbols on the telegraph line. It worked by two rods alternately rising up to sample the holes in the tape. First of all the top hole was probed, and if the rod could go through, it moved a compound lever that connected the mark signal to the line. With no hole the lever remained unmoved. Next the top hole rod dropped and the bottom hole rod checked whether there was a bottom hole in the tape. If there was, the compound lever was moved back to connect the space signal on the line. If there was no hole, the compound lever was left alone as it was. An extra switch enabled the transmitter to be bypassed so that a Morse key could be used instead.

The Wheatstone receiver converted the signal on the telegraph line to an inked pattern on a paper strip. An electromagnet electrically connected to the telegraph line moved an inking wheel to press against the paper. A clockwork mechanism advanced the paper tape, and turned the inking wheel, and an ink supply wheel. The paper advance speed could be adjusted between 7 and 60 feet per minute. Power to the clockwork had three sources: it could be a coiled spring, a weight, or an electric motor. Paper spools were stored in drawers beneath the reader to allow quick change when one was exhausted. The ink supply wheel turned in an inkwell. The machine was started and stopped by use of a lever. In electrical characteristics, the electromagnet had two windings, each of 100 ohms resistance. These could be connected in parallel or series to achieve a 50 or 200 ohm resistance, to better match the telegraph line. Other maintenance that might have been required was cleaning of the marker and supply wheels, adjusting the armature-coil spacing to avoid a marking or spacing bias, and cleaning the sounding tongue and contact points.

The Wheatstone telegram consisted of strips of paper tape with the Morse code printed on it, pasted on a form. The telegram would later be retyped to make a final presentable message for the recipient.

🔗 Finance & Investment 🔗 Economics 🔗 Food and drink 🔗 Food and drink/Foodservice 🔗 Retailing 🔗 Globalization

The Big Mac Index is a price index published by The Economist as an informal way of measuring the purchasing power parity (PPP) between two currencies and provides a test of the extent to which market exchange rates result in goods costing the same in different countries. It "seeks to make exchange-rate theory a bit more digestible."

The index, created in 1986, takes its name from the Big Mac, a hamburger sold at McDonald's restaurants.

🔗 Volcanoes 🔗 Islands 🔗 Sicily 🔗 Seamounts

Graham Island (also Graham Bank or Graham Shoal; Italian: Isola Ferdinandea) is a submerged volcanic island in the Mediterranean Sea. It was discovered when it last appeared on 1 August 1831 by Humphrey Fleming Senhouse, the captain of the first rate Royal Navy ship of the line St Vincent and named after Sir James Graham, the First Lord of the Admiralty. It was claimed by the United Kingdom. It forms part of the underwater volcano Empedocles, 30 km (19 mi) south of Sicily, and which is one of a number of submarine volcanoes known as the Campi Flegrei del Mar di Sicilia. Seamount eruptions have raised it above sea level several times before erosion submerged it again.

When it last rose above sea level after erupting in 1831, a four-way dispute over its sovereignty began, which was still unresolved when it disappeared beneath the waves again in early 1832. During its brief life, French geologist Constant Prévost was on hand, accompanied by an artist, to witness it in July 1831; he named it Île Julia, for its July appearance, and reported in the Bulletin de la Société Géologique de France. Some observers at the time wondered if a chain of mountains would spring up, linking Sicily to Tunisia and thus upsetting the geopolitics of the region. It showed signs of volcanic activity in 2000 and 2002, forecasting a possible appearance; however, as of 2016 it remains 6 m (20 ft) under sea level.

🔗 Mathematics

In number theory, the Green–Tao theorem, proved by Ben Green and Terence Tao in 2004, states that the sequence of prime numbers contains arbitrarily long arithmetic progressions. In other words, for every natural number k, there exist arithmetic progressions of primes with k terms. The proof is an extension of Szemerédi's theorem. The problem can be traced back to investigations of Lagrange and Waring from around 1770.

🔗 Germany 🔗 Archaeology 🔗 Germany/Hamburg

The Ovelgönne Bread Roll is the remaining part of a bread roll originating from the Pre-Roman Iron Age of Northern Europe, which was found in 1952 during archaeological excavations in a loam mine in the Buxtehude district Ovelgönne in Lower Saxony, Germany. The piece of bread is the oldest surviving viennoiserie and formed bakery product from Europe. The find, along with a reconstruction, are in the permanent exhibition of the Archaeological Museum Hamburg in Harburg, Hamburg.

🔗 Computing

The Fifth Generation Computer Systems (FGCS) was an initiative by Japan's Ministry of International Trade and Industry (MITI), begun in 1982, to create computers using massively parallel computing and logic programming. It was to be the result of a massive government/industry research project in Japan during the 1980s. It aimed to create an "epoch-making computer" with supercomputer-like performance and to provide a platform for future developments in artificial intelligence. There was also an unrelated Russian project also named as a fifth-generation computer (see Kronos (computer)).

Prof. Ehud Shapiro, in his "Trip Report" paper (which focused the FGCS project on concurrent logic programming as the software foundation for the project), captured the rationale and motivations driving this huge project:

"As part of Japan's effort to become a leader in the computer industry, the Institute for New Generation Computer Technology has launched a revolutionary ten-year plan for the development of large computer systems which will be applicable to knowledge information processing systems. These Fifth Generation computers will be built around the concepts of logic programming. In order to refute the accusation that Japan exploits knowledge from abroad without contributing any of its own, this project will stimulate original research and will make its results available to the international research community."

The term "fifth generation" was intended to convey the system as being a leap beyond existing machines. In the history of computing hardware, computers using vacuum tubes were called the first generation; transistors and diodes, the second; integrated circuits, the third; and those using microprocessors, the fourth. Whereas previous computer generations had focused on increasing the number of logic elements in a single CPU, the fifth generation, it was widely believed at the time, would instead turn to massive numbers of CPUs for added performance.

The project was to create the computer over a ten-year period, after which it was considered ended and investment in a new "sixth generation" project would begin. Opinions about its outcome are divided: either it was a failure, or it was ahead of its time.

🔗 United States 🔗 Film 🔗 Library of Congress 🔗 Film/American cinema 🔗 United States/Film - American cinema 🔗 Science Fiction 🔗 Transhumanism 🔗 Guild of Copy Editors 🔗 Film/Core 🔗 Film/British cinema 🔗 Hertfordshire

2001: A Space Odyssey is a 1968 epic science fiction film produced and directed by Stanley Kubrick. The screenplay was written by Kubrick and science fiction author Arthur C. Clarke, and was inspired by Clarke's 1951 short story "The Sentinel" and other short stories by Clarke. Clarke also published a novelisation of the film, in part written concurrently with the screenplay, after the film's release. The film stars Keir Dullea, Gary Lockwood, William Sylvester, and Douglas Rain, and follows a voyage by astronauts, scientists and the sentient supercomputer HAL to Jupiter to investigate an alien monolith.

The film is noted for its scientifically accurate depiction of space flight, pioneering special effects, and ambiguous imagery. Kubrick avoided conventional cinematic and narrative techniques; dialogue is used sparingly, and there are long sequences accompanied only by music. The soundtrack incorporates numerous works of classical music, by composers including Richard Strauss, Johann Strauss II, Aram Khachaturian, and György Ligeti.

The film received diverse critical responses, ranging from those who saw it as darkly apocalyptic to those who saw it as an optimistic reappraisal of the hopes of humanity. Critics noted its exploration of themes such as human evolution, technology, artificial intelligence, and the possibility of extraterrestrial life. It was nominated for four Academy Awards, winning Kubrick the award for his direction of the visual effects. The film is now widely regarded as one of the greatest and most influential films ever made. In 1991, it was selected by the United States Library of Congress for preservation in the National Film Registry. In 2022, 2001: A Space Odyssey placed in the top ten of Sight & Sound's decennial critics' poll, and topped their directors' poll.

🔗 United Kingdom 🔗 Trains 🔗 Ireland

In British and Irish rail transport, a slip coach or slip carriage is passenger rolling stock that is uncoupled from an express train while the train is in motion, then slowed by a guard in the coach using the brakes, bringing it to a stop at the next station. The coach was thus said to be slipped from its train. This allowed passengers to alight at an intermediate station without the main train having to stop, thus improving the journey time of the main train. In an era when the railway companies were highly competitive, they strove to keep journey times as short as possible, avoiding intermediate stops wherever possible.