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🔗 Highways 🔗 Road transport 🔗 Highways/Road transport

A diverging diamond interchange (DDI), also called a double crossover diamond interchange (DCD), is a type of diamond interchange in which the two directions of traffic on the non-freeway road cross to the opposite side on both sides of the bridge at the freeway. It is unusual in that it requires traffic on the freeway overpass (or underpass) to briefly drive on the opposite side of the road from what is customary for the jurisdiction. The crossover "X" sections can either be traffic-light intersections or one-side overpasses to travel above the opposite lanes without stopping, to allow nonstop traffic flow when relatively sparse traffic.

Like the continuous flow intersection, the diverging diamond interchange allows for two-phase operation at all signalized intersections within the interchange. This is a significant improvement in safety, since no long turns (e.g. left turns where traffic drives on the right side of the road) must clear opposing traffic and all movements are discrete, with most controlled by traffic signals. Its at-grade variant can be seen as a two-leg continuous flow intersection.

Additionally, the design can improve the efficiency of an interchange, as the lost time for various phases in the cycle can be redistributed as green time—there are only two clearance intervals (the time for traffic signals to change from green to yellow to red) instead of the six or more found in other interchange designs.

A diverging diamond can be constructed for limited cost, at an existing straight-line bridge, by building crisscross intersections outside the bridge ramps to switch traffic lanes before entering the bridge. The switchover lanes, each with 2 side ramps, introduce a new risk of drivers turning onto an empty, wrong-way, do-not-enter, exit lane and driving the wrong way down a freeway exit ramp to confront high-speed, oncoming traffic. Studies have analyzed various roadsigns to reduce similar driver errors.

Diverging diamond roads have been used in France since the 1970s. However, the diverging diamond interchange was listed by Popular Science magazine as one of the best innovations in 2009 (engineering category) in "Best of What's New 2009".

The design also is promoted as part of the Federal Highway Administration's Every Day Counts initiative which started in 2011.

🔗 Philosophy 🔗 Psychology 🔗 Philosophy/Ancient philosophy 🔗 Philosophy/Ethics

Akrasia (; Greek ἀκρασία, "lacking command" or "weakness", occasionally transliterated as acrasia or Anglicised as acrasy or acracy) is a lack of self-control, or acting against one's better judgment. Beginning with Plato, a variety of philosophers have attempted to determine whether or not akrasia exists and how to best define it.

🔗 Internet 🔗 Computing 🔗 Internet culture 🔗 Freedom of speech 🔗 Computing/Software 🔗 Computing/Computer Security 🔗 Popular Culture 🔗 Lincolnshire

The Scunthorpe problem is the unintentional blocking of websites, e-mails, forum posts or search results by a spam filter or search engine because their text contains a string of letters that appear to have an obscene or otherwise unacceptable meaning. Names, abbreviations, and technical terms are most often cited as being affected by the issue.

The problem arises since computers can easily identify strings of text within a document, but interpreting words of this kind requires considerable ability to interpret a wide range of contexts, possibly across many cultures, which is an extremely difficult task. As a result, broad blocking rules may result in false positives affecting innocent phrases.

🔗 Literature

The Thirty-Six Dramatic Situations is a descriptive list which was first proposed by Georges Polti in 1895 to categorize every dramatic situation that might occur in a story or performance. Polti analyzed classical Greek texts, plus classical and contemporaneous French works. He also analyzed a handful of non-French authors. In his introduction, Polti claims to be continuing the work of Carlo Gozzi, who also identified 36 situations.

🔗 History 🔗 Mathematics 🔗 Books 🔗 Greece 🔗 History of Science

The Archimedes Palimpsest is a parchment codex palimpsest, originally a Byzantine Greek copy of a compilation of Archimedes and other authors. It contains two works of Archimedes that were thought to have been lost (the Ostomachion and the Method of Mechanical Theorems) and the only surviving original Greek edition of his work On Floating Bodies. The first version of the compilation is believed to have been produced by Isidorus of Miletus, the architect of the geometrically complex Hagia Sophia cathedral in Constantinople, sometime around AD 530. The copy found in the palimpsest was created from this original, also in Constantinople, during the Macedonian Renaissance (c. AD 950), a time when mathematics in the capital was being revived by the former Greek Orthodox bishop of Thessaloniki Leo the Geometer, a cousin of the Patriarch.

Following the sack of Constantinople by Western crusaders in 1204, the manuscript was taken to an isolated Greek monastery in Palestine, possibly to protect it from occupying crusaders, who often equated Greek script with heresy against their Latin church and either burned or looted many such texts (including at least two other copies of Archimedes). The complex manuscript was not appreciated at this remote monastery and was soon overwritten (1229) with a religious text. In 1899, nine hundred years after it was written, the manuscript was still in the possession of the Greek church, and back in Istanbul, where it was catalogued by the Greek scholar Papadopoulos-Kerameus, attracting the attention of Johan Heiberg. Heiberg visited the church library and was allowed to make detailed photographs in 1906. Most of the original text was still visible, and Heiberg published it in 1915. In 1922 the manuscript went missing in the midst of the evacuation of the Greek Orthodox library in Istanbul, during a tumultuous period following the World War I. Concealed for over 70 years by a Western businessman, forged pictures were painted on top of some text to increase resale value. Unable to sell the book privately, in 1998 the businessman's daughter risked a public auction in New York contested by the Greek church; the U.S. court ruled for the auction, and the manuscript was purchased by an anonymous buyer (rumored to be Jeff Bezos). The texts under the forged pictures, and previously unreadable texts, were revealed by analyzing images produced by ultraviolet, infrared, visible and raking light, and X-ray.

All images and transcriptions are now freely available on the web at the Archimedes Digital Palimpsest under the Creative Commons License CC BY.

In 2011, Randall Munroe in his comic xkcd coined the term "citogenesis" to describe the creation of "reliable" sources through circular reporting. This is a list of some well-documented cases where Wikipedia has been the source.

🔗 Electronics

In signal processing, the Nyquist frequency (or folding frequency), named after Harry Nyquist, is a characteristic of a sampler, which converts a continuous function or signal into a discrete sequence. For a given sampling rate (samples per second), the Nyquist frequency (cycles per second) is the frequency whose cycle-length (or period) is twice the interval between samples, thus 0.5 cycle/sample. For example, audio CDs have a sampling rate of 44100 samples/second. At 0.5 cycle/sample, the corresponding Nyquist frequency is 22050 cycles/second (Hz). Conversely, the Nyquist rate for sampling a 22050 Hz signal is 44100 samples/second.

When the highest frequency (bandwidth) of a signal is less than the Nyquist frequency of the sampler, the resulting discrete-time sequence is said to be free of the distortion known as aliasing, and the corresponding sample rate is said to be above the Nyquist rate for that particular signal.

In a typical application of sampling, one first chooses the highest frequency to be preserved and recreated, based on the expected content (voice, music, etc.) and desired fidelity. Then one inserts an anti-aliasing filter ahead of the sampler. Its job is to attenuate the frequencies above that limit. Finally, based on the characteristics of the filter, one chooses a sample rate (and corresponding Nyquist frequency) that will provide an acceptably small amount of aliasing. In applications where the sample rate is pre-determined (such as the CD rate), the filter is chosen based on the Nyquist frequency, rather than vice versa.

🔗 Architecture 🔗 Classical Greece and Rome

The Roman architectural revolution, also known as the concrete revolution, is the name sometimes given to the widespread use in Roman architecture of the previously little-used architectural forms of the arch, vault, and dome. For the first time in history, their potential was fully exploited in the construction of a wide range of civil engineering structures, public buildings, and military facilities. These included amphitheatres, aqueducts, baths, bridges, circuses, dams, roads, and temples.

A crucial factor in this development that saw a trend to monumental architecture was the invention of Roman concrete (also called opus caementicium), which led to the liberation of the shape from the dictate of the traditional materials of stone and brick.

For the first time in recorded history we find evidence of an interest in the shapes of the space contained strong enough to outweigh the functional logic of the masonry masses that contained it. There was nothing new in the employment of curvilinear or polygonal forms, as such...But in so far as such buildings incorporated curvilinear or polygonal rooms and corridors, the shapes of these were determined by the form of the building as a whole, not by any aesthetic principle.

The development of Roman architecture, however, did not remain limited to these new forms and materials. An unrelated process of architectural innovation continued unabated, which, although less conspicuous, proved their usefulness for solving structural problems and found their way permanently into Western architecture, such as the lintel arch, the independent corbel, and the metal-tie.

During the Age of Augustus, almost the entire city of Rome was rebuilt causing an influx of craftsman and architects from all across Europe. Emperor Augustus aimed to develop new ideas in the construction of his buildings that would forever defy the limits that were ever thought possible. The Mausoleum in Campus Martius was one of the major monuments built by Augustus during his reign that was made almost entirely of concrete using updated construction techniques. The concrete is used in concentric rings that support the structure of the building like walls. The Theatre of Marcellus was another concrete triumph completed during the Age of Augustus, dedicated to the nephew of the emperor. The brick-faced concrete structure construction started under Julius Caesar but was completed under Augustus. It was this building that shows the integration of new concrete building techniques of Augustus's architects as opposed to those of Caesar. The Theatre of Marcellus uses a variety of materials that aid in the growth of the concrete revolution using readily available volcanic stones such as Tuscolo tuff and Tufo Lionato as aggregates in pozzolanic concretes.

These newly concocted recipes for concrete provided durability to walls and barrelled vaults as well as a unique aesthetic appeal. The integrated stone and masonry design illustrate a refinement that came with the concrete revolution as a result of the new techniques and styles developed under Augustus. The craftsmanship of the Theatre Marcellus demonstrated a skilled employment as well as rigorous technical supervision.

🔗 Agriculture 🔗 Indigenous peoples of North America

The Three Sisters are the three main agricultural crops of various Indigenous peoples of North America: squash, maize ("corn"), and climbing beans (typically tepary beans or common beans). In a technique known as companion planting, the maize and beans are often planted together in mounds formed by hilling soil around the base of the plants each year; squash is typically planted between the mounds. The cornstalk serves as a trellis for climbing beans, the beans fix nitrogen in their root nodules and stabilize the maize in high winds, and the wide leaves of the squash plant shade the ground, keeping the soil moist and helping prevent the establishment of weeds.

Indigenous peoples throughout North America cultivated different varieties of the Three Sisters, adapted to varying local environments. The individual crops and their use in polyculture originated in Mesoamerica; where squash was domesticated first, followed by maize and then beans, over a period of 5,000–6,500 years. European records from the sixteenth century describe highly productive Indigenous agriculture based on cultivation of the Three Sisters throughout what are now the Eastern United States and Canada, where the crops were used for both food and trade. Geographer Carl O. Sauer described the Three Sisters as "a symbiotic plant complex of North and Central America without an equal elsewhere".