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🔗 Mathematics 🔗 Percussion

To hear the shape of a drum is to infer information about the shape of the drumhead from the sound it makes, i.e., from the list of overtones, via the use of mathematical theory.

"Can One Hear the Shape of a Drum?" is the title of a 1966 article by Mark Kac in the American Mathematical Monthly which made the question famous, though this particular phrasing originates with Lipman Bers. Similar questions can be traced back all the way to Hermann Weyl . For his paper, Kac was given the Lester R. Ford Award in 1967 and the Chauvenet Prize in 1968.

The frequencies at which a drumhead can vibrate depend on its shape. The Helmholtz equation calculates the frequencies if the shape is known. These frequencies are the eigenvalues of the Laplacian in the space. A central question is whether the shape can be predicted if the frequencies are known; for example, whether a circle-shaped triangle can be recognized in this way. Kac admitted he did not know if it was possible for two different shapes to yield the same set of frequencies. The question of whether the frequencies determine the shape was finally answered in the negative in the early 1990s by Gordon, Webb and Wolpert.

🔗 Military history 🔗 Military history/Military science, technology, and theory 🔗 Military history/Weaponry 🔗 Elements 🔗 Military history/Cold War

Red mercury is purportedly a substance of uncertain composition used in the creation of nuclear weapons, as well as other weapons systems. Because of the great secrecy surrounding the development and manufacture of nuclear weapons, there is no proof that red mercury exists. However, all samples of alleged "red mercury" analyzed in the public literature have proven to be well-known, common red substances of no interest to weapons makers.

Red mercury is therefore considered a hoax, perpetrated by con artists who sought to take advantage of gullible buyers on the black market for arms. There have been reports of "red mercury" on the international black markets since 1979, but the hoax seems to have been most common in the early 1990s, with very high asking prices.

🔗 Military history 🔗 Heraldry and vexillology 🔗 Catholicism 🔗 Military history/Crusades 🔗 Military history/Medieval warfare 🔗 Countries 🔗 Former countries 🔗 Military history/National militaries 🔗 Malta 🔗 Orders, decorations, and medals

The Sovereign Military Order of Malta (SMOM), officially the Sovereign Military Hospitaller Order of Saint John of Jerusalem, of Rhodes and of Malta (Italian: Sovrano Militare Ordine Ospedaliero di San Giovanni di Gerusalemme di Rodi e di Malta; Latin: Supremus Militaris Ordo Hospitalarius Sancti Ioannis Hierosolymitani Rhodiensis et Melitensis), commonly known as the Order of Malta, Malta Order or Knights of Malta, is a Catholic lay religious order, traditionally of military, chivalric and noble nature. Though it possesses no territory, the order is a sovereign entity of international law and maintains diplomatic relations with many countries.

SMOM claims continuity with the Knights Hospitaller, a chivalric order that was founded c. 1099 by the Blessed Gerard in the Kingdom of Jerusalem. The order is led by an elected Prince and Grand Master. Its motto is Tuitio fidei et obsequium pauperum ('defence of the faith and assistance to the poor'). The order venerates the Virgin Mary as its patroness, under the title of Our Lady of Philermos. Its modern-day role is largely focused on providing humanitarian assistance and assisting with international humanitarian relations, for which purpose it has had permanent observer status at the United Nations General Assembly since 1994.

🔗 Computing 🔗 Computing/Early computers

The TX-0, for Transistorized Experimental computer zero, but affectionately referred to as tixo (pronounced "tix oh"), was an early fully transistorized computer and contained a then-huge 64K of 18-bit words of magnetic core memory. Construction of the TX-0 began in 1955 and ended in 1956. It was used continually through the 1960s at MIT. The TX-0 incorporated around 3600 Philco high-frequency surface-barrier transistors, the first transistor suitable for high-speed computers. The TX-0 and its direct descendant, the original PDP-1, were platforms for pioneering computer research and the development of what would later be called computer "hacker" culture.

🔗 Computing

Simula is the name of two simulation programming languages, Simula I and Simula 67, developed in the 1960s at the Norwegian Computing Center in Oslo, by Ole-Johan Dahl and Kristen Nygaard. Syntactically, it is a fairly faithful superset of ALGOL 60, also influenced by the design of Simscript.

Simula 67 introduced objects, classes, inheritance and subclasses, virtual procedures, coroutines, and discrete event simulation, and features garbage collection. Also other forms of subtyping (besides inheriting subclasses) were introduced in Simula derivatives.

Simula is considered the first object-oriented programming language. As its name suggests, the first Simula version by 1962 was designed for doing simulations; Simula 67 though was designed to be a general-purpose programming language and provided the framework for many of the features of object-oriented languages today.

Simula has been used in a wide range of applications such as simulating very-large-scale integration (VLSI) designs, process modeling, communication protocols, algorithms, and other applications such as typesetting, computer graphics, and education. The influence of Simula is often understated, and Simula-type objects are reimplemented in C++, Object Pascal, Java, C#, and many other languages. Computer scientists such as Bjarne Stroustrup, creator of C++, and James Gosling, creator of Java, have acknowledged Simula as a major influence.

🔗 Aviation

Balloonomania was a strong public interest or fad in balloons that originated in France in the late 18th century and continued into the 19th century, during the advent of balloon flights. The interest began with the first flights of the Montgolfier brothers in 1783 (in a balloon inflated with hot air). Soon afterwards Jacques Alexandre César Charles flew another type of balloon (inflated with hydrogen) and both types of balloon were in use from then on. The fad quickly spread in France and across the channel in England.

🔗 Mass surveillance 🔗 Computing 🔗 Internet culture 🔗 Philosophy 🔗 Cryptography 🔗 Cryptography/Computer science 🔗 Numismatics 🔗 Sociology 🔗 Numismatics/Cryptocurrency 🔗 Computing/Computer Security 🔗 Philosophy/Anarchism 🔗 Anarchism

Crypto-anarchism (or crypto-anarchy) is a political ideology focusing on protection of privacy, political freedom and economic freedom, the adherents of which use cryptographic software for confidentiality and security while sending and receiving information over computer networks.

By using cryptographic software, the association between the identity of a certain user or organization and the pseudonym they use is made difficult to find, unless the user reveals the association. It is difficult to say which country's laws will be ignored, as even the location of a certain participant is unknown. However, participants may in theory voluntarily create new laws using smart contracts or, if the user is pseudonymous, depend on online reputation.

🔗 Computing 🔗 Computing/Software 🔗 Numismatics 🔗 Numismatics/Cryptocurrency 🔗 Cryptocurrency

Gridcoin (ticker: GRC) is an open source cryptocurrency which securely rewards volunteer computing performed on the BOINC, a distributed computing platform that is home to over 30 science projects spanning a range of scientific disciplines.

Gridcoin attempts to address and ease the environmental energy impact of cryptocurrency mining through its proof-of-research and proof-of-stake protocols, as compared to the proof of work system used by Bitcoin.

🔗 United States/U.S. Government 🔗 United States 🔗 Finance & Investment 🔗 Economics 🔗 Numismatics

The everything bubble refers to the correlated impact of monetary easing by the Federal Reserve (and followed by the ECB and the BOJ), on asset prices in most asset classes, namely equities, housing, bonds, many commodities, and even exotic assets such as cryptocurrencies and SPACs. The term is related to the Fed put, being the tools of direct and indirect quantative easing that the Fed used to execute the monetary easing, and to modern monetary theory, which advocates use of such tools, even in non-crisis periods, to create economic growth through asset price inflation. The term first came in use during the chair of Janet Yellen, but it is most associated with the subsequent chair of Jerome Powell, and the 2020–2021 period of the coronavirus pandemic.

The everything bubble was not only notable for the simultaneous extremes in valuations recorded in a wide range of asset classes and the high level of speculation in the market, but also that this was achieved in a period of recession, high unemployment, trade wars, and political turmoil – leading to a realization that it was uniquely a central bank creation, with concerns on the independence and integrity of market pricing, and on the Fed's impact on wealth inequality.

Bloomberg attributed Powell's maintenance of monetary stimulus into 2021 (the final year of his first term as Fed chair), in spite of warnings of unprecedented levels of market risk and speculation, to his fear of repeating the crash in Q4 2018 when he started quantitative tightening; thus extending the bubble.

High up on his [President Biden] list, and sooner rather than later, will be dealing with the consequences of the biggest financial bubble in U.S. history. Why the biggest? Because it encompasses not just stocks but pretty much every other financial asset too. And for that, you may thank the Federal Reserve.

🔗 Food and drink 🔗 Open 🔗 Food and drink/Beverages

Open-source cola is any cola soft drink produced according to a published and shareable recipe. Unlike the secretive Coca-Cola formula, the recipes are openly published and their re-use is encouraged. The texts of OpenCola and Cube-Cola recipes are published under the GNU General Public License (GPL).