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🔗 Mathematics

Pentagramma mirificum (Latin for miraculous pentagram) is a star polygon on a sphere, composed of five great circle arcs, all of whose internal angles are right angles. This shape was described by John Napier in his 1614 book Mirifici logarithmorum canonis descriptio (Description of the wonderful rule of logarithms) along with rules that link the values of trigonometric functions of five parts of a right spherical triangle (two angles and three sides). The properties of pentagramma mirificum were studied, among others, by Carl Friedrich Gauss.

Rocky Mountain BASIC (also RMB or RM-BASIC) is a dialect of the BASIC programming language created by Hewlett-Packard. It was especially popular for control of automatic test equipment using GPIB. It has several features which are or were unusual in BASIC dialects, such as event-driven operation, extensive external I/O support, complex number support, and matrix manipulation functions. Today, RMB is mainly used in environments where an investment in RMB software, hardware, or expertise already exists.

🔗 Technology 🔗 Internet culture 🔗 Visual arts 🔗 Computer graphics 🔗 Artificial Intelligence

Slop is low-quality media—including writing and images—made using generative artificial intelligence technology. Coined in the 2020s, the term has a derogatory connotation akin to "spam".

It has been variously defined as "digital clutter", "filler content produced by AI tools that prioritize speed and quantity over substance and quality", and "shoddy or unwanted AI content in social media, art, books and, increasingly, in search results".

Jonathan Gilmore, Professor of Philosophy at the City University of New York, describes the "incredibly banal, realistic style" of AI slop as being "very easy to process".

🔗 Mathematics 🔗 Maps

The coastline paradox is the counterintuitive observation that the coastline of a landmass does not have a well-defined length. This results from the fractal curve-like properties of coastlines, i.e., the fact that a coastline typically has a fractal dimension (which in fact makes the notion of length inapplicable). The first recorded observation of this phenomenon was by Lewis Fry Richardson and it was expanded upon by Benoit Mandelbrot.

The measured length of the coastline depends on the method used to measure it and the degree of cartographic generalization. Since a landmass has features at all scales, from hundreds of kilometers in size to tiny fractions of a millimeter and below, there is no obvious size of the smallest feature that should be taken into consideration when measuring, and hence no single well-defined perimeter to the landmass. Various approximations exist when specific assumptions are made about minimum feature size.

The problem is fundamentally different from the measurement of other, simpler edges. It is possible, for example, to accurately measure the length of a straight, idealized metal bar by using a measurement device to determine that the length is less than a certain amount and greater than another amount—that is, to measure it within a certain degree of uncertainty. The more accurate the measurement device, the closer results will be to the true length of the edge. When measuring a coastline, however, the closer measurement does not result in an increase in accuracy—the measurement only increases in length; unlike with the metal bar, there is no way to obtain a maximum value for the length of the coastline.

In three-dimensional space, the coastline paradox is readily extended to the concept of fractal surfaces whereby the area of a surface varies, depending on the measurement resolution.

🔗 Physics

A Bessel beam is a wave whose amplitude is described by a Bessel function of the first kind. Electromagnetic, acoustic, gravitational, and matter waves can all be in the form of Bessel beams. A true Bessel beam is non-diffractive. This means that as it propagates, it does not diffract and spread out; this is in contrast to the usual behavior of light (or sound), which spreads out after being focused down to a small spot. Bessel beams are also self-healing, meaning that the beam can be partially obstructed at one point, but will re-form at a point further down the beam axis.

As with a plane wave, a true Bessel beam cannot be created, as it is unbounded and would require an infinite amount of energy. Reasonably good approximations can be made, however, and these are important in many optical applications because they exhibit little or no diffraction over a limited distance. Approximations to Bessel beams are made in practice either by focusing a Gaussian beam with an axicon lens to generate a Bessel–Gauss beam, by using axisymmetric diffraction gratings, or by placing a narrow annular aperture in the far field. High order Bessel beams can be generated by spiral diffraction gratings.

🔗 Food and drink 🔗 Iceland

Although Iceland is reliant upon fishing, tourism and aluminium production as the mainstays of its economy, the production of vegetables and fruit in greenhouses is a growing sector. Until the 1960s this included commercial production of bananas.

In 1941, the first bananas in Iceland were produced. They have been produced since that time, about 100 clusters a year each about 5–20 kg (11–44 lb), but are not currently sold. In the wake of World War II, the combination of inexpensive geothermal power (which had recently become available) and high prices for imported fruit led to the construction of a number of greenhouses where bananas were produced commercially from 1945 to as late as 1958 or 1959. In 1960, the government removed import duties on fruit. Domestically grown bananas were no longer able to compete with imported ones and soon disappeared from the market. Icelandic banana production was much slower due to low levels of sunlight; Icelandic bananas took two years to mature, while it only takes a few months near the equator.

The urban myth that Iceland is Europe’s largest producer or exporter of bananas has been propagated in various books and other media. It was mentioned, in an episode of the BBC quiz programme QI, and on a forum connected with the show. According to FAO statistics, the largest European producer of bananas is France (in Martinique and Guadeloupe), followed by Spain (primarily in the Canary Islands). Other banana-producing countries in Europe include Portugal (on Madeira), Greece, and Italy.

Although a small number of banana plants still exist in greenhouses and produce fruit every year, Iceland imports nearly all of the bananas consumed in the country, with imports now amounting to over 18 kg (40 lb) per capita per annum. The Agricultural University of Iceland maintains the last such farm with 600-700 banana plants in its tropical greenhouse, which were received as donations from producers when they shut down (then the Horticultural College). Bananas grown there are consumed by the students and staff and are not sold.

🔗 Engineering

Ephemeralization, a term coined by R. Buckminster Fuller in 1938, is the ability of technological advancement to do "more and more with less and less until eventually you can do everything with nothing," that is, an accelerating increase in the efficiency of achieving the same or more output (products, services, information, etc.) while requiring less input (effort, time, resources, etc.). Fuller's vision was that ephemeralization will result in ever-increasing standards of living for an ever-growing population despite finite resources. The concept has been embraced by those who argue against Malthusian philosophy. The subsequently coined economics term "dematerialization" refers to essentially the same concept as also does eco-economic decoupling.

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.

🔗 Technology 🔗 Computing 🔗 Electronics 🔗 Engineering

Electrochemical Random-Access Memory (ECRAM) is a type of non-volatile memory (NVM) with multiple levels per cell (MLC) designed for deep learning analog acceleration. An ECRAM cell is a three-terminal device composed of a conductive channel, an insulating electrolyte, an ionic reservoir, and metal contacts. The resistance of the channel is modulated by ionic exchange at the interface between the channel and the electrolyte upon application of an electric field. The charge-transfer process allows both for state retention in the absence of applied power, and for programming of multiple distinct levels, both differentiating ECRAM operation from that of a field-effect transistor (FET). The write operation is deterministic and can result in symmetrical potentiation and depression, making ECRAM arrays attractive for acting as artificial synaptic weights in physical implementations of artificial neural networks (ANN). The technological challenges include open circuit potential (OCP) and semiconductor foundry compatibility associated with energy materials. Universities, government laboratories, and corporate research teams have contributed to the development of ECRAM for analog computing. Notably, Sandia National Laboratories designed a lithium-based cell inspired by solid-state battery materials, Stanford University built an organic proton-based cell, and International Business Machines (IBM) demonstrated in-memory selector-free parallel programming for a logistic regression task in an array of metal-oxide ECRAM designed for insertion in the back end of line (BEOL). In 2022, researchers at Massachusetts Institute of Technology built an inorganic, CMOS-compatible protonic technology that achieved near-ideal modulation characteristics using nanosecond fast pulses

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

GNU Guix () is a functional cross-platform package manager and a tool to instantiate and manage Unix-like operating systems, based on the Nix package manager. Configuration and package recipes are written in Guile Scheme. GNU Guix is the default package manager of the GNU Guix System distribution.

Differing from traditional package managers, Guix (like Nix) utilizes a purely functional deployment model where software is installed into unique directories generated through cryptographic hashes. All dependencies for each software are included within each hash. This solves the problem of dependency hell, allows multiple versions of the same software to coexist and makes packages portable and reproducible. Performing scientific computations in a Guix setup has been proposed as a promising response to the replication crisis.

The development of GNU Guix is intertwined with the GNU Guix System, an installable operating system distribution using the Linux-libre kernel and GNU Shepherd init system.