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🔗 Mathematics

A hinged dissection, also known as a swing-hinged dissection or Dudeney dissection, is a kind of geometric dissection in which all of the pieces are connected into a chain by "hinged" points, such that the rearrangement from one figure to another can be carried out by swinging the chain continuously, without severing any of the connections. Typically, it is assumed that the pieces are allowed to overlap in the folding and unfolding process; this is sometimes called the "wobbly-hinged" model of hinged dissection.

🔗 Computing 🔗 Computing/Software 🔗 Computing/Free and open-source software

Coherent is a clone of the Unix operating system for IBM PC compatibles and other microcomputers, developed and sold by the now-defunct Mark Williams Company (MWC). Historically, the operating system was a proprietary product, but it became open source in 2015, released under a 3-clause BSD License.

🔗 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".

🔗 Sociology

Computational sociology is a branch of sociology that uses computationally intensive methods to analyze and model social phenomena. Using computer simulations, artificial intelligence, complex statistical methods, and analytic approaches like social network analysis, computational sociology develops and tests theories of complex social processes through bottom-up modeling of social interactions.

It involves the understanding of social agents, the interaction among these agents, and the effect of these interactions on the social aggregate. Although the subject matter and methodologies in social science differ from those in natural science or computer science, several of the approaches used in contemporary social simulation originated from fields such as physics and artificial intelligence. Some of the approaches that originated in this field have been imported into the natural sciences, such as measures of network centrality from the fields of social network analysis and network science.

In relevant literature, computational sociology is often related to the study of social complexity. Social complexity concepts such as complex systems, non-linear interconnection among macro and micro process, and emergence, have entered the vocabulary of computational sociology. A practical and well-known example is the construction of a computational model in the form of an "artificial society", by which researchers can analyze the structure of a social system.

🔗 Psychology 🔗 Education 🔗 Homeschooling 🔗 Alternative education

Autodidacticism (also autodidactism) or self-education (also self-learning and self-teaching) is education without the guidance of masters (such as teachers and professors) or institutions (such as schools). Generally, an autodidact is an individual who chooses the subject they will study, their studying material, and the studying rhythm and time. An autodidact may or may not have formal education, and their study may be either a complement or an alternative to formal education. Many notable contributions have been made by autodidacts.

🔗 Computing 🔗 Libraries

"As We May Think" is a 1945 essay by Vannevar Bush which has been described as visionary and influential, anticipating many aspects of information society. It was first published in The Atlantic in July 1945 and republished in an abridged version in September 1945—before and after the atomic bombings of Hiroshima and Nagasaki. Bush expresses his concern for the direction of scientific efforts toward destruction, rather than understanding, and explicates a desire for a sort of collective memory machine with his concept of the memex that would make knowledge more accessible, believing that it would help fix these problems. Through this machine, Bush hoped to transform an information explosion into a knowledge explosion.

🔗 Biography 🔗 France 🔗 Philosophy 🔗 Biography/science and academia 🔗 Philosophy/Philosophers 🔗 Philosophy/Epistemology 🔗 Philosophy/Modern philosophy 🔗 Libertarianism

Michel Eyquem, Seigneur de Montaigne ( mon-TAYN; French: [miʃɛl ekɛm də mɔ̃tɛɲ]; 28 February 1533 – 13 September 1592), known as Michel de Montaigne, was one of the most significant philosophers of the French Renaissance. He is known for popularizing the essay as a literary genre. His work is noted for its merging of casual anecdotes and autobiography with intellectual insight. Montaigne had a direct influence on numerous Western writers; his massive volume Essais contains some of the most influential essays ever written.

During his lifetime, Montaigne was admired more as a statesman than as an author. The tendency in his essays to digress into anecdotes and personal ruminations was seen as detrimental to proper style rather than as an innovation, and his declaration that "I am myself the matter of my book" was viewed by his contemporaries as self-indulgent. In time, however, Montaigne came to be recognized as embodying, perhaps better than any other author of his time, the spirit of freely entertaining doubt that began to emerge at that time. He is most famously known for his skeptical remark, ''Que sçay-je?" ("What do I know?", in Middle French; now rendered as "Que sais-je?" in modern French).

🔗 Computing 🔗 Time

The Day of the Programmer is an international professional day that is celebrated on the 256th (hexadecimal 100th, or the 2⁸th) day of each year (September 13 during common years and on September 12 in leap years). It is officially recognized in Russia.

The number 256 (2⁸) was chosen because it is the number of distinct values that can be represented with a byte, a value well known to programmers. 256 is also the highest power of two that is less than 365, the number of days in a common year.

🔗 Biography 🔗 Mathematics 🔗 Philosophy 🔗 Philosophy/Logic 🔗 Philosophy/Social and political philosophy 🔗 Biography/science and academia 🔗 Philosophy/Philosophy of science 🔗 Linguistics 🔗 Linguistics/Theoretical Linguistics 🔗 Philosophy/Philosophers 🔗 Philosophy/Epistemology 🔗 Sociology 🔗 Politics of the United Kingdom 🔗 Philosophy/Philosophy of language 🔗 Chicago 🔗 Philosophy/Metaphysics 🔗 Linguistics/Philosophy of language 🔗 Philosophy/Analytic philosophy 🔗 Atheism 🔗 Biography/Peerage and Baronetage

Bertrand Arthur William Russell, 3rd Earl Russell, (18 May 1872 – 2 February 1970) was a British philosopher, logician, mathematician, historian, writer, essayist, social critic, political activist, and Nobel laureate. At various points in his life, Russell considered himself a liberal, a socialist and a pacifist, although he also confessed that his sceptical nature had led him to feel that he had "never been any of these things, in any profound sense." Russell was born in Monmouthshire into one of the most prominent aristocratic families in the United Kingdom.

In the early 20th century, Russell led the British "revolt against idealism". He is considered one of the founders of analytic philosophy along with his predecessor Gottlob Frege, colleague G. E. Moore and protégé Ludwig Wittgenstein. He is widely held to be one of the 20th century's premier logicians. With A. N. Whitehead he wrote Principia Mathematica, an attempt to create a logical basis for mathematics, the quintessential work of classical logic. His philosophical essay "On Denoting" has been considered a "paradigm of philosophy". His work has had a considerable influence on mathematics, logic, set theory, linguistics, artificial intelligence, cognitive science, computer science (see type theory and type system) and philosophy, especially the philosophy of language, epistemology and metaphysics.

Russell was a prominent anti-war activist and he championed anti-imperialism. Occasionally, he advocated preventive nuclear war, before the opportunity provided by the atomic monopoly had passed and he decided he would "welcome with enthusiasm" world government. He went to prison for his pacifism during World War I. Later, Russell concluded that war against Adolf Hitler's Nazi Germany was a necessary "lesser of two evils" and criticised Stalinist totalitarianism, attacked the involvement of the United States in the Vietnam War and was an outspoken proponent of nuclear disarmament. In 1950, Russell was awarded the Nobel Prize in Literature "in recognition of his varied and significant writings in which he champions humanitarian ideals and freedom of thought".