Have a deep view into what people are curious about.

🔗 Mathematics

The Ulam spiral or prime spiral is a graphical depiction of the set of prime numbers, devised by mathematician Stanisław Ulam in 1963 and popularized in Martin Gardner's Mathematical Games column in Scientific American a short time later. It is constructed by writing the positive integers in a square spiral and specially marking the prime numbers.

Ulam and Gardner emphasized the striking appearance in the spiral of prominent diagonal, horizontal, and vertical lines containing large numbers of primes. Both Ulam and Gardner noted that the existence of such prominent lines is not unexpected, as lines in the spiral correspond to quadratic polynomials, and certain such polynomials, such as Euler's prime-generating polynomial x² − x + 41, are believed to produce a high density of prime numbers. Nevertheless, the Ulam spiral is connected with major unsolved problems in number theory such as Landau's problems. In particular, no quadratic polynomial has ever been proved to generate infinitely many primes, much less to have a high asymptotic density of them, although there is a well-supported conjecture as to what that asymptotic density should be.

In 1932, more than thirty years prior to Ulam's discovery, the herpetologist Laurence Klauber constructed a triangular, non-spiral array containing vertical and diagonal lines exhibiting a similar concentration of prime numbers. Like Ulam, Klauber noted the connection with prime-generating polynomials, such as Euler's.

🔗 Sociology

Toilet paper when used with a toilet roll holder with a horizontal axle parallel to both the wall and the floor has two possible orientations: the toilet paper may hang over (in front of) or under (behind) the roll.

Some people hold strong opinions on the matter; advice columnist Ann Landers said that the subject was the most responded to (15,000 letters in 1986) and controversial issue in her column's history. Defenders of either position cite advantages ranging from aesthetics, hospitality, and cleanliness to paper conservation, ease of detaching sheets, and compatibility with pets. Some writers have proposed connections to age, sex, or political philosophy, and survey evidence has shown a correlation with socioeconomic status.

Solutions where the views of household members differ include using separate dispensers or separate bathrooms and ignoring the issue. One man advocates a plan under which his country will standardize on a single forced orientation, and at least one inventor hopes to popularize a new kind of toilet roll holder which swivels from one orientation to the other.

🔗 Aviation 🔗 Aviation/aircraft 🔗 Aviation/gliding

The yaw string, also known as a slip string, is a simple device for indicating a slip or skid in an aircraft in flight. It performs the same function as the slip-skid indicator ball, but is more sensitive, and does not require the pilot to look down at the instrument panel. Technically, it measures sideslip angle, not yaw angle, but this indicates how the aircraft must be yawed to return the sideslip angle to zero.

It is typically constructed from a short piece or tuft of yarn placed in the free air stream where it is visible to the pilot. In closed-cockpit aircraft, it is usually taped to the aircraft canopy. It may also be mounted on the aircraft's nose, either directly on the skin, or elevated on a mast, in which case it may also be fitted with a small paper cone at the trailing end. They are commonly used on gliders, but may also be found on jet aircraft (especially fighters), ultralight aircraft, light-sport aircraft, autogyros, airplanes and helicopters. Its usefulness on airplanes with a tractor configuration (single propeller at the nose) is limited because the propeller creates turbulence and the spiral slipstream displaces the string to one side.

The yaw string is considered a primary flight reference instrument on gliders, which must be flown with near zero sideslip angle to reduce drag as much as possible. It is valued for its high sensitivity, and the fact that it is presented in a head-up display. Even the most sophisticated modern racing sailplanes are fitted with yaw strings by their pilots, who reference them constantly throughout the flight.

🔗 Computing 🔗 Statistics 🔗 Computational Biology

The following is a list of algorithms along with one-line descriptions for each.

🔗 Archaeology 🔗 Wiltshire

The Stonehenge Archer is the name given to a Bronze Age man whose body was discovered in the outer ditch of Stonehenge. Unlike most burials in the Stonehenge Landscape, his body was not in a barrow, although it did appear to have been deliberately and carefully buried in the ditch.

Examination of the skeleton indicated that the man was local to the area and aged about 30 when he died. Radiocarbon dating suggests that he died around 2300 BCE, making his death roughly contemporary with the Amesbury Archer and the Boscombe Bowmen buried 3 miles away in Amesbury.

He came to be known as an archer because of the stone wrist-guard and a number of flint arrowheads buried with him. In fact, several of the arrowheads' tips were located in the skeleton's bones, suggesting that the man had been killed by them.

His body was excavated in 1978 by Richard Atkinson and John G. Evans who had been re-examining an older trench in the ditch and bank of Stonehenge. His remains are now housed in the Salisbury Museum in Salisbury.

🔗 Companies 🔗 Finance & Investment 🔗 Lists 🔗 Business 🔗 Business/Accounting

This page lists the largest annual and quarterly earnings and losses in corporate history. In general terms the oil and gas industry is the one generating both largest annual and quarterly earnings. In contrast, both the annual and quarterly losses are more distributed across industries.

🔗 Death 🔗 Law 🔗 Romania

The trial of Nicolae and Elena Ceaușescu was held on 25 December 1989 by an Exceptional Military Tribunal, a drumhead court-martial created at the request of a newly formed group called the National Salvation Front. Its outcome was pre-determined, and it resulted in guilty verdicts and death sentences for former Romanian President and Romanian Communist Party General Secretary, Nicolae Ceaușescu, and his wife, Elena Ceaușescu.

The main charge was genocide— namely, murdering "over 60,000 people" during the revolution in Timișoara. Other sources put the death toll between 689 and 1,200. Nevertheless, the charges did not affect the trial. General Victor Stănculescu had brought with him a specially selected team of paratroopers from a crack regiment, handpicked earlier in the morning to act as a firing squad. Before the legal proceedings began, Stănculescu had already selected the spot where the execution would take place: along one side of the wall in the barracks' square.

Nicolae Ceaușescu refused to recognize the tribunal, arguing its lack of constitutional basis and claiming that the revolutionary authorities were part of a Soviet plot.

🔗 Aviation

A cyclorotor, cycloidal rotor, cycloidal propeller or cyclogiro, is a fluid propulsion device that converts shaft power into the acceleration of a fluid using a rotating axis perpendicular to the direction of fluid motion. It uses several blades with a spanwise axis parallel to the axis of rotation and perpendicular to the direction of fluid motion. These blades are cyclically pitched twice per revolution to produce force (thrust or lift) in any direction normal to the axis of rotation. Cyclorotors are used for propulsion, lift, and control on air and water vehicles. An aircraft using cyclorotors as the primary source of lift, propulsion, and control is known as a cyclogyro or cyclocopter. A unique aspect is that it can change the magnitude and direction of thrust without the need of tilting any aircraft structures. The patented application, used on ships with particular actuation mechanisms both mechanical or hydraulic, is named after German company Voith Turbo.

🔗 Extinction

An endling is the last known individual of a species or subspecies. Once the endling dies, the species becomes extinct. The word was coined in correspondence in the scientific journal Nature. Alternative names put forth for the last individual of its kind include ender and terminarch.

The word relict may also be used, but usually refers to a population, rather than an individual, that is the last of a species.

🔗 Ancient Near East 🔗 Novels 🔗 Novels/Science fiction 🔗 Science Fiction 🔗 Skepticism 🔗 Literature 🔗 Classical Greece and Rome 🔗 Greece 🔗 Comedy 🔗 Assyria

A True Story (Ancient Greek: Ἀληθῆ διηγήματα, Alēthē diēgēmata; Latin: Vera Historia or Latin: Verae Historiae) is a novel written in the second century AD by Lucian of Samosata, a Greek-speaking author of Assyrian descent. The novel is a satire of outlandish tales which had been reported in ancient sources, particularly those which presented fantastic or mythical events as if they were true. It is Lucian's best-known work.

It is the earliest known work of fiction to include travel to outer space, alien lifeforms, and interplanetary warfare. As such, A True Story has been described as "the first known text that could be called science fiction". However the work does not fit into typical literary genres: its multilayered plot and characters have been interpreted as science fiction, fantasy, satire or parody, and have been the subject of much scholarly debate.