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🔗 Physics 🔗 Geology 🔗 Physics/Acoustics

Singing sand, also called whistling sand, barking sand or singing dune, is sand that produces sound. The sound emission may be caused by wind passing over dunes or by walking on the sand.

Certain conditions have to come together to create singing sand:

1. The sand grains have to be round and between 0.1 and 0.5 mm in diameter.
2. The sand has to contain silica.
3. The sand needs to be at a certain humidity.

The most common frequency emitted seems to be close to 450 Hz.

There are various theories about the singing sand mechanism. It has been proposed that the sound frequency is controlled by the shear rate. Others have suggested that the frequency of vibration is related to the thickness of the dry surface layer of sand. The sound waves bounce back and forth between the surface of the dune and the surface of the moist layer, creating a resonance that increases the sound's volume. The noise may be generated by friction between the grains or by the compression of air between them.

Other sounds that can be emitted by sand have been described as "roaring" or "booming".

🔗 Biography 🔗 Biography/arts and entertainment 🔗 Chicago 🔗 Photography 🔗 Photography/History of photography 🔗 Women artists

Vivian Dorothy Maier (February 1, 1926 – April 21, 2009) was an American street photographer whose work was not discovered and recognized until after her death. She worked for about forty years as a nanny, mostly in Chicago's North Shore, while she pursued her photography. She took more than 150,000 photographs during her lifetime, primarily of the people and architecture of Chicago, New York City, and Los Angeles, although she also traveled and photographed worldwide.

During her lifetime, Maier's photographs were unknown and unpublished; many of her negatives were never printed. A Chicago collector, John Maloof, acquired some of Maier's photos in 2007, while two other Chicago-based collectors, Ron Slattery and Randy Prow, also found some of Maier's prints and negatives in her boxes and suitcases around the same time. Maier's photographs were first published on the Internet in July 2008, by Slattery, but the work received little response. In October 2009, Maloof linked his blog to a selection of Maier's photographs on the image-sharing website Flickr, and the results went viral, with thousands of people expressing interest. Maier's work subsequently attracted critical acclaim, and since then, Maier's photographs have been exhibited around the world.

Her life and work have been the subject of books and documentary films, including the film Finding Vivian Maier (2013), which premiered at the Toronto International Film Festival, and was nominated for the Academy Award for Best Documentary Feature at the 87th Academy Awards.

🔗 Linguistics 🔗 Linguistics/Applied Linguistics

SHRDLU was an early natural language understanding computer program, developed by Terry Winograd at MIT in 1968–1970. In it, the user carries on a conversation with the computer, moving objects, naming collections and querying the state of a simplified "blocks world", essentially a virtual box filled with different blocks.

SHRDLU was written in the Micro Planner and Lisp programming language on the DEC PDP-6 computer and a DEC graphics terminal. Later additions were made at the computer graphics labs at the University of Utah, adding a full 3D rendering of SHRDLU's "world".

The name SHRDLU was derived from ETAOIN SHRDLU, the arrangement of the letter keys on a Linotype machine, arranged in descending order of usage frequency in English.

🔗 Statistics 🔗 Futures studies

The Delphi method or Delphi technique ( DEL-fy; also known as Estimate-Talk-Estimate or ETE) is a structured communication technique or method, originally developed as a systematic, interactive forecasting method which relies on a panel of experts. The technique can also be adapted for use in face-to-face meetings, and is then called mini-Delphi or Estimate-Talk-Estimate (ETE). Delphi has been widely used for business forecasting and has certain advantages over another structured forecasting approach, prediction markets.

Delphi is based on the principle that forecasts (or decisions) from a structured group of individuals are more accurate than those from unstructured groups. The experts answer questionnaires in two or more rounds. After each round, a facilitator or change agent provides an anonymised summary of the experts' forecasts from the previous round as well as the reasons they provided for their judgments. Thus, experts are encouraged to revise their earlier answers in light of the replies of other members of their panel. It is believed that during this process the range of the answers will decrease and the group will converge towards the "correct" answer. Finally, the process is stopped after a predefined stop criterion (e.g., number of rounds, achievement of consensus, stability of results), and the mean or median scores of the final rounds determine the results.

Special attention has to be paid to the formulation of the Delphi theses and the definition and selection of the experts in order to avoid methodological weaknesses that severely threaten the validity and reliability of the results.

🔗 Philosophy 🔗 Philosophy/Philosophical literature 🔗 Books 🔗 Philosophy/Contemporary philosophy

The Accursed Share: An Essay on General Economy (French: La Part maudite) is a 1949 book about political economy by the French intellectual Georges Bataille, in which the author presents a new economic theory which he calls "general economy". The work comprises Volume I: Consumption, Volume II: The History of Eroticism, and Volume III: Sovereignty. It was first published in France by Les Éditions de Minuit, and in the United States by Zone Books. It is considered one of the most important of Bataille's books.

🔗 Books 🔗 Transhumanism 🔗 Alternative Views

Engines of Creation: The Coming Era of Nanotechnology is a 1986 molecular nanotechnology book written by K. Eric Drexler with a foreword by Marvin Minsky. An updated version was released in 2007. The book has been translated into Japanese, French, Spanish, Italian, Russian, and Chinese.

🔗 France 🔗 Transport

The carrosses à cinq sols (English: five-sol coaches) were the first modern form of public transport in the world, developed by mathematician and philosopher Blaise Pascal.

🔗 Psychology 🔗 Women's History 🔗 Discrimination 🔗 Gender Studies 🔗 Men's Issues

The women-are-wonderful effect is the phenomenon found in psychological and sociological research which suggests that people associate more positive attributes with women compared to men. This bias reflects an emotional bias toward women as a general case. The phrase was coined by Alice Eagly and Antonio Mladinic in 1994 after finding that both male and female participants tend to assign positive traits to women, with female participants showing a far more pronounced bias. Positive traits were assigned to men by participants of both genders, but to a far lesser degree.

The authors supposed that the positive general evaluation of women might derive from the association between women and nurturing characteristics. This bias is suggested as a form of misandry/'benevolent misogyny', the latter being a concept within the theoretical framework of ambivalent sexism.

🔗 Biography 🔗 Russia 🔗 Biography/science and academia 🔗 Russia/science and education in Russia

Anatoli Petrovich Bugorski (Russian: Анатолий Петрович Бугорский), born 25 June 1942, is a Russian scientist.

🔗 Astronomy 🔗 Geology

The Eltanin impact is thought to be an asteroid impact in the eastern part of the South Pacific Ocean during the Pliocene-Pleistocene boundary around 2.51 ± 0.07  million years ago. The location was at the edge of the Bellingshausen Sea 1,500 km (950 mi) southwest of Chile. The asteroid was estimated to be about one to four km (0.6 to 2.5 mi) in diameter and the impact would have left a crater approximately 35 km (22 mi) across.