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🔗 Mathematics

The expression "casting out nines" may refer to any one of three arithmetical procedures:

• Adding the decimal digits of a positive whole number, while optionally ignoring any 9s or digits which sum to a multiple of 9. The result of this procedure is a number which is smaller than the original whenever the original has more than one digit, leaves the same remainder as the original after division by nine, and may be obtained from the original by subtracting a multiple of 9 from it. The name of the procedure derives from this latter property.
• Repeated application of this procedure to the results obtained from previous applications until a single-digit number is obtained. This single-digit number is called the "digital root" of the original. If a number is divisible by 9, its digital root is 9. Otherwise, its digital root is the remainder it leaves after being divided by 9.
• A sanity test in which the above-mentioned procedures are used to check for errors in arithmetical calculations. The test is carried out by applying the same sequence of arithmetical operations to the digital roots of the operands as are applied to the operands themselves. If no mistakes are made in the calculations, the digital roots of the two resultants should be the same. If they are different, therefore, one or more mistakes must have been made in the calculations.

🔗 Environment 🔗 Urban studies and planning 🔗 Chicago 🔗 Illinois

The Tunnel and Reservoir Plan (abbreviated TARP and more commonly known as the Deep Tunnel Project or the Chicago Deep Tunnel) is a large civil engineering project that aims to reduce flooding in the metropolitan Chicago area, and to reduce the harmful effects of flushing raw sewage into Lake Michigan by diverting storm water and sewage into temporary holding reservoirs. The megaproject is one of the largest civil engineering projects ever undertaken in terms of scope, cost and timeframe. Commissioned in the mid-1970s, the project is managed by the Metropolitan Water Reclamation District of Greater Chicago. Completion of the system is not anticipated until 2029, but substantial portions of the system have already opened and are currently operational. Across 30 years of construction, over $3 billion has been spent on the project.

🔗 Africa 🔗 Cats 🔗 Mammals 🔗 Africa/Western Sahara

The sand cat (Felis margarita), also known as the sand dune cat, is the only cat living chiefly in true deserts. This small cat is widely distributed in the deserts of North Africa, the Middle East and Central Asia. Starting in 2002, it was listed as near threatened on the IUCN Red List because the population was considered fragmented and small with a declining trend. It was downlisted to least concern in 2016.

Owing to long hairs covering the soles of its feet, the sand cat is well adapted to the extremes of a desert environment and tolerant of extremely hot and cold temperatures. It inhabits both sandy and stony deserts, in areas far from water sources.

🔗 Russia 🔗 Russia/mass media in Russia 🔗 Radio Stations

The Pip is the nickname given by radio listeners to a shortwave radio station that broadcasts on the frequency 5448 kHz by day, and 3756 kHz during the night. It broadcasts short, repeated beeps at a rate of around 50 per minute, for 24 hours per day. The beep signal is occasionally interrupted by voice messages in Russian. The Pip has been active since around 1985, when its distinctive beeping sound was first recorded by listeners.

The station is commonly referred to as "The Pip" among English-speaking radio listeners. In Russia, it is known as Капля (Kaplya) "the drop". While its official name or callsign is not known, some of the voice transmissions begin with the code 8S1Shch (Cyrillic: 8С1Щ), which is generally considered to be the name of the station. However, this code may not be a callsign, but instead serve some other purpose. Radioscanner.ru identifies the owner of this station as a North-Caucasian military district communication center with callsign "Akacia" (ex-72nd communication center, Russian "72 узел связи штаба СКВО").

🔗 Electronics

The Williams tube, or the Williams–Kilburn tube after inventors Freddie Williams and Tom Kilburn, is an early form of computer memory. It was the first random-access digital storage device, and was used successfully in several early computers.

The Williams tube works by displaying a grid of dots on a cathode ray tube (CRT). Due to the way CRTs work, this creates a small charge of static electricity over each dot. The charge at the location of each of the dots is read by a thin metal sheet just in front of the display. Since the display faded over time, it was periodically refreshed. It cycles faster than earlier acoustic delay line memory, at the speed of the electrons inside the vacuum tube, rather than at the speed of sound. However, the system was adversely affected by any nearby electrical fields, and required constant alignment to keep operational. Williams–Kilburn tubes were used primarily on high-speed computer designs.

Williams and Kilburn applied for British patents on 11 December 1946, and 2 October 1947, followed by United States patent applications on 10 December 1947, and 16 May 1949.

🔗 Video games 🔗 Computer science 🔗 Science

A human-based computation game or game with a purpose (GWAP) is a human-based computation technique of outsourcing steps within a computational process to humans in an entertaining way (gamification).

Luis von Ahn first proposed the idea of "human algorithm games", or games with a purpose (GWAPs), in order to harness human time and energy for addressing problems that computers cannot yet tackle on their own. He believes that human intellect is an important resource and contribution to the enhancement of computer processing and human computer interaction. He argues that games constitute a general mechanism for using brainpower to solve open computational problems. In this technique, human brains are compared to processors in a distributed system, each performing a small task of a massive computation. However, humans require an incentive to become part of a collective computation. Online games are used as a means to encourage participation in the process.

The tasks presented in these games are usually trivial for humans, but difficult for computers. These tasks include labeling images, transcribing ancient texts, common sense or human experience based activities, and more. Human-based computation games motivate people through entertainment rather than an interest in solving computation problems. This makes GWAPs more appealing to a larger audience. GWAPs can be used to help build the semantic web, annotate and classify collected data, crowdsource general knowledge, and improving other general computer processes. GWAPs have a vast range of applications in variety of areas such as security, computer vision, Internet accessibility, adult content filtering, and Internet search. In applications such as these, games with a purpose have lowered the cost of annotating data and increased the level of human participation.

🔗 Military history 🔗 Military history/North American military history 🔗 Military history/United States military history 🔗 Food and drink 🔗 Military history/Russian, Soviet and CIS military history 🔗 Food and drink/Beverages

White Coke (Russian: Бесцветная кока-кола, tr. Bestsvetnaya koka-kola, lit. "colorless Coca-Cola") is a nickname for a clear variant of Coca-Cola produced in the 1940s at the request of Marshal of the Soviet Union Georgy Zhukov. Like other clear colas, it was of the same original flavor, virtually unchanged by the absence of caramel coloring.

🔗 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.

🔗 Biography 🔗 Syria

Bassel Khartabil (Arabic: باسل خرطبيل‎), also known as Bassel Safadi (Arabic: باسل صفدي‎), (22 May 1981, Damascus – 3 October 2015) was a Palestinian Syrian open-source software developer. On 15 March 2012, the one-year anniversary of the Syrian uprising, he was detained by the Syrian government at Adra Prison in Damascus. Between then and 3 October 2015, he had been transferred to an unknown location, probably to be judged by a military court. On 7 October 2015, Human Rights Watch and 30 other human rights organizations issued a letter demanding that Khartabil's whereabouts be disclosed. On 11 November 2015, rumors surfaced that Khartabil had been secretly sentenced to death. In August 2017, his wife made public that Khartabil had been executed by the Syrian regime shortly after his disappearance in 2015.

Khartabil was born in Damascus and raised in Syria, where he specialized in open source software development. He was chief technology officer (CTO) and co-founder of collaborative research company Aiki Lab and was CTO of Al-Aous, a publishing and research institution dedicated to archaeological sciences and arts in Syria. He has served as project lead and public affiliate for Creative Commons Syria, and has contributed to Mozilla Firefox, Wikipedia, Openclipart, Fabricatorz, and Sharism. He "is credited with opening up the Internet in Syria and vastly extending online access and knowledge to the Syrian people."

His last work included an open, 3D virtual reconstruction of the ancient city of Palmyra in Syria, real time visualization, and development with Fabricatorz for the web programming framework Aiki Framework. This was later created and displayed in his honor.

On February 7, 2018, the Bassel Khartabil Free Culture Fellowship was announced in Bassel's memory. The fellowship awards $50,000, including additional support, to outstanding individuals developing open culture in their communities. The fellowship was created by Creative Commons, Fabricatorz Foundation, Jimmy Wales Foundation, Mozilla, #NEWPALMYRA, and Wikimedia.

🔗 Technology 🔗 Africa 🔗 Finance & Investment 🔗 Africa/Tanzania 🔗 Afghanistan 🔗 Africa/Kenya

M-Pesa (M for mobile, pesa is Swahili for money) is a mobile phone-based money transfer, financing and microfinancing service, launched in 2007 by Vodafone for Safaricom and Vodacom, the largest mobile network operators in Kenya and Tanzania. It has since expanded to Afghanistan, South Africa, India and in 2014 to Romania and in 2015 to Albania. M-Pesa allows users to deposit, withdraw, transfer money and pay for goods and services (Lipa na M-Pesa) easily with a mobile device.

The service allows users to deposit money into an account stored on their cell phones, to send balances using PIN-secured SMS text messages to other users, including sellers of goods and services, and to redeem deposits for regular money. Users are charged a small fee for sending and withdrawing money using the service.

M-Pesa is a branchless banking service; M-Pesa customers can deposit and withdraw money from a network of agents that includes airtime resellers and retail outlets acting as banking agents.

M-Pesa has spread quickly, and by 2010 had become the most successful mobile-phone-based financial service in the developing world. By 2012, a stock of about 17 million M-Pesa accounts had been registered in Kenya. By June 2016, a total of 7 million M-Pesa accounts have been opened in Tanzania by Vodacom. The service has been lauded for giving millions of people access to the formal financial system and for reducing crime in otherwise largely cash-based societies.