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🔗 China

"I would rather cry in a BMW" is a quotation that became an online sensation in the People's Republic of China in 2010. The old, long-familiar phrase was made famous by Ma Nuo, a 20-year-old female contestant on the television show Fei Cheng Wu Rao (also known in English as If You Are the One). The line was in response to a question by an unemployed suitor who asked if Ma would "ride a bicycle with him" on a date. The series of events have been summed up in the media with the quip "I would rather cry in a BMW than smile on a bicycle."

🔗 United States 🔗 Aviation 🔗 Military history 🔗 Military history/Military aviation 🔗 Military history/North American military history 🔗 Military history/United States military history 🔗 Aviation/aircraft

The Lockheed CL-1201 was a design study by Lockheed for a giant 6,000 ton nuclear-powered transport aircraft in the late 1960s. One envisioned use of the concept was as an airborne aircraft carrier.

🔗 Biology 🔗 Molecular and Cell Biology 🔗 Genetics

DNA origami is the nanoscale folding of DNA to create non-arbitrary two- and three-dimensional shapes at the nanoscale. The specificity of the interactions between complementary base pairs make DNA a useful construction material, through design of its base sequences. DNA is a well-understood material that is suitable for creating scaffolds that hold other molecules in place or to create structures all on its own.

DNA origami was the cover story of Nature on March 16, 2006. Since then, DNA origami has progressed past an art form and has found a number of applications from drug delivery systems to uses as circuitry in plasmonic devices; however, most applications remain in a concept or testing phase.

🔗 London 🔗 British Museum 🔗 BBC 🔗 Classical Greece and Rome 🔗 Archaeology 🔗 Rome 🔗 East Anglia 🔗 East Anglia/Suffolk

The Hoxne Hoard ( HOK-sən) is the largest hoard of late Roman silver and gold discovered in Britain, and the largest collection of gold and silver coins of the fourth and fifth centuries found anywhere within the former Roman Empire. It was found by Eric Lawes, a metal detectorist in the village of Hoxne in Suffolk, England in 1992. The hoard consists of 14,865 Roman gold, silver, and bronze coins and approximately 200 items of silver tableware and gold jewellery. The objects are now in the British Museum in London, where the most important pieces and a selection of the rest are on permanent display. In 1993, the Treasure Valuation Committee valued the hoard at £1.75 million (about £3.79 million in 2021).

The hoard was buried in an oak box or small chest filled with items in precious metal, sorted mostly by type, with some in smaller wooden boxes and others in bags or wrapped in fabric. Remnants of the chest and fittings, such as hinges and locks, were recovered in the excavation. The coins of the hoard date it after AD 407, which coincides with the end of Britain as a Roman province. The owners and reasons for burial of the hoard are unknown, but it was carefully packed and the contents appear consistent with what a single very wealthy family might have owned. It is likely that the hoard represents only a part of the wealth of its owner, given the lack of large silver serving vessels and of some of the most common types of jewellery.

The Hoxne Hoard contains several rare and important objects, such as a gold body-chain and silver-gilt pepper-pots (piperatoria), including the Empress pepper pot. The hoard is also of particular archaeological significance because it was excavated by professional archaeologists with the items largely undisturbed and intact. The find helped to improve the relationship between metal detectorists and archaeologists, and influenced a change in English law regarding finds of treasure.

🔗 Electronic music

The Atari Punk Console (commonly shortened to APC) is a popular circuit that utilizes two 555 timer ICs or a single 556 dual timer IC. The original circuit, called a "Sound Synthesizer", was published in a Radio Shack booklet: "Engineer's Notebook: Integrated Circuit Applications" in 1980 and later called "Stepped Tone Generator" in "Engineer's Mini-Notebook - 555 Circuits" by its designer, Forrest M. Mims III (Siliconcepts, 1984). It was named "Atari Punk Console" (APC) by Kaustic Machines crew because its "low-fi" sounds resemble classic Atari console games from the 1980s, with a square wave output similar to the Atari 2600. Kaustic Machines added a -4db line level output with volume control to the circuit which was originally designed to drive a small 8-ohm speaker.

The Atari Punk console is an astable square wave oscillator driving a monostable oscillator that creates a single (square) pulse. There are two controls, one for the frequency of the oscillator and one to control the pulse width. The controls are usually potentiometers but the circuit can also be controlled by light, temperature, pressure etc. by replacing a potentiometer with a suitable sensor (e.g., photoresistor for light sensitivity). Most of the time there is also a power switch (often a toggle switch) and a volume knob.

The circuit is a simple DIY noisemaker circuit that is relatively inexpensive and easy to build, easily adaptable and is configurable in many ways. It has been built into a wide variety of cases. Its flexibility has led to wide scale popularity among electronics enthusiasts. It is often suggested as a good circuit to build for beginners.

🔗 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.

🔗 Mathematics

Actuarial notation is a shorthand method to allow actuaries to record mathematical formulas that deal with interest rates and life tables.

Traditional notation uses a halo system where symbols are placed as superscript or subscript before or after the main letter. Example notation using the halo system can be seen below.

Various proposals have been made to adopt a linear system where all the notation would be on a single line without the use of superscripts or subscripts. Such a method would be useful for computing where representation of the halo system can be extremely difficult. However, a standard linear system has yet to emerge.

🔗 Musical Instruments 🔗 Percussion

A lithophone is a musical instrument consisting of a rock or pieces of rock which are struck to produce musical notes. Notes may be sounded in combination (producing harmony) or in succession (melody). The lithophone is an idiophone comparable to instruments such as the glockenspiel, vibraphone, xylophone and marimba.

In the Hornbostel-Sachs classification system, lithophones are designated as '111.22' – directly-struck percussion plaques.

🔗 Trains 🔗 Trains/Operations

Signalling block systems enable the safe and efficient operation of railways by preventing collisions between trains. The basic principle is that a route is broken up into a series of sections or "blocks". Only one train may occupy a block at a time, and the blocks are sized to allow a train to stop within them. That ensures that a train always has time to stop before getting dangerously close to another train on the same line. The block system is referred to in the UK as the method of working, in the US as the method of operation, and in Australia as safeworking.

In most situations, a system of signals is used to control the passage of trains between the blocks. When a train enters a block, signals at both ends change to indicate that the block is occupied, typically using red lamps or indicator flags. When a train first enters a block, the rear of the same train has not yet left the previous block, so both blocks are marked as occupied. That ensures there is slightly less than one block length on either end of the train that is marked as occupied, so any other train approaching that section will have enough room to stop in time, even if the first train has stopped dead on the tracks. The previously-occupied block will only be marked unoccupied when the end of the train has entirely left it, leaving the entire block clear.

Block systems have the disadvantage that they limit the number of trains on a particular route to something fewer than the number of blocks. Since the route has a fixed length, increasing the number of trains requires the creation of more blocks, which means the blocks are shorter and trains have to operate at lower speeds in order to stop safely. As a result, the number and size of blocks are closely related to the overall route capacity, and cannot be changed easily because expensive alterations to the signals along the line would be required.

Block systems are used to control trains between stations and yards, but not normally within the yards, where some other method is used. Any block system is defined by its associated physical equipment and by the application of a relevant set of rules. Some systems involve the use of signals while others do not. Some systems are specifically designed for single track railways, on which there is a danger of both head-on and rear-end collision, as opposed to double track, on which the main danger is rear-end collisions.

🔗 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.