Have a deep view into what people are curious about.

🔗 Video games 🔗 Computing 🔗 Books

Rules of Play: Game Design Fundamentals is a book on game design by Katie Salen and Eric Zimmerman, published by MIT Press.

🔗 Visual arts 🔗 Morocco

Zellige (Arabic: [zˈliʑ]; Arabic: الزليج‎; also zelige or zellij or zileej) is mosaic tilework made from individually chiseled geometric tiles set into a plaster base. This form of Islamic art is one of the main characteristics of Moroccan architecture. It consists of geometrically patterned mosaics, used to ornament walls, ceilings, fountains, floors, pools and tables. The Moroccan traditional patterns and styles are found inside famous buildings such as Al-Qarawiyyin Mosque in Fez, the Alhambra in Granada, Spain, the Great Mosque of Cordoba, the Ben Youssef Madrasa in Marrakech, and the Hassan II mosque in Casablanca, which adds a new color palette with traditional designs.

🔗 Psychology

Transactional analysis (TA) is a psychoanalytic theory and method of therapy wherein social transactions are analyzed to determine the ego state of the patient (whether parent-like, childlike, or adult-like) as a basis for understanding behavior. In transactional analysis, the patient is taught to alter the ego state as a way to solve emotional problems. The method deviates from Freudian psychoanalysis which focuses on increasing awareness of the contents of unconsciously held ideas. Eric Berne developed the concept and paradigm of transactional analysis in the late 1950s.

🔗 Fire Service 🔗 Forestry 🔗 Wildfire

Smokejumpers are specially trained wildland firefighters who provide an initial attack response on remote wildland fires. They are inserted at the site of the fire by parachute.

Smokejumpers are trained and experienced wildland firefighters. In addition to performing the initial attack on wildfires, they may also provide leadership for extended attacks on wildland fires. Shortly after smokejumpers touch ground, they are supplied by parachute with food, water, and firefighting tools, making them self-sufficient for 48 hours. Smokejumpers are usually on duty from early spring through late fall.

🔗 Computing 🔗 Computing/Software 🔗 Computing/Amiga

Amiga Unix (informally known as Amix) is a discontinued full port of AT&T Unix System V Release 4 operating system developed by Commodore-Amiga, Inc. in 1990 for the Amiga computer family as an alternative to AmigaOS, which shipped by default. Bundled with the Amiga 3000UX, Commodore's Unix was one of the first ports of SVR4 to the 68k architecture. The Amiga A3000UX model even got the attention of Sun Microsystems, though ultimately nothing came of it.

Unlike Apple's A/UX, Amiga Unix contained no compatibility layer to allow AmigaOS applications to run under Unix. With few native applications available to take advantage of the Amiga's significant multimedia capabilities, it failed to find a niche in the quite-competitive Unix workstation market of the early 1990s. The A3000UX's price tag of $4,998 (equivalent to $9,382 in 2019) was also not very attractive compared to other Unix workstations at the time, such as the NeXTstation ($5,000 for a base system, with a full API and many times the number of applications available), the SGI Indigo (starting at $8,000), or the Personal DECstation 5000 Model 25 (starting at $5,000). Sun, HP, and IBM had similarly priced systems. The A3000UX's 68030 was noticeably underpowered compared to most of its RISC-based competitors.

Unlike typical commercial Unix distributions of the time, Amiga Unix included the source code to the vendor-specific enhancements and platform-dependent device drivers (essentially any part that wasn't owned by AT&T), allowing interested users to study or enhance those parts of the system. However this source code was subject to the same license terms as the binary part of the system – it was not free software. Amiga Unix also incorporated and depended upon many open source components, such as the GNU C Compiler and X Window System, and included their source code.

Like many other proprietary Unix variants with small market shares, Amiga Unix vanished into the mists of computer history when its vendor, Commodore, went out of business. Today, Unix-like operating systems such as Minix, NetBSD, and Linux are available for the Amiga platform.

🔗 Geography 🔗 Romania 🔗 Ecology 🔗 Caves

Movile Cave (Romanian: Peștera Movile) is a cave near Mangalia, Constanța County, Romania discovered in 1986 by Cristian Lascu a few kilometers from the Black Sea coast. It is notable for its unique groundwater ecosystem abundant in hydrogen sulfide and carbon dioxide, but low in oxygen. Life in the cave has been separated from the outside for the past 5.5 million years and it is based completely on chemosynthesis rather than photosynthesis.

🔗 Molecular and Cell Biology 🔗 Neuroscience 🔗 Physiology 🔗 Physiology/cell

Brainbow is a process by which individual neurons in the brain can be distinguished from neighboring neurons using fluorescent proteins. By randomly expressing different ratios of red, green, and blue derivatives of green fluorescent protein in individual neurons, it is possible to flag each neuron with a distinctive color. This process has been a major contribution to the field of connectomics, traditionally known as hodology, which is the study of neural connections in the brain.

The technique was originally developed in 2007 by a team led by Jeff W. Lichtman and Joshua R. Sanes, both at Harvard University. The original technique has recently been adapted for use with other model organisms including Drosophila melanogaster, Caenorhabditis elegans, and Arabidopsis thaliana.

While earlier labeling techniques allowed for the mapping of only a few neurons, this new method allows more than 100 differently mapped neurons to be simultaneously and differentially illuminated in this manner. The resulting images can be quite striking and have won awards in science photography competitions.

🔗 United States/U.S. Government 🔗 United States 🔗 Mass surveillance 🔗 Cryptography 🔗 Cryptography/Computer science

The Clipper chip was a chipset that was developed and promoted by the United States National Security Agency (NSA) as an encryption device that secured “voice and data messages" with a built-in backdoor. It was intended to be adopted by telecommunications companies for voice transmission. It can encipher and decipher messages. It was part of a Clinton Administration program to “allow Federal, State, and local law enforcement officials the ability to decode intercepted voice and data transmissions." “Each clipper chip ha[d] a unique serial number and a secret ‘unit key,’ programmed into the chip when manufactured." This way, each device was meant to be different from the next.

It was announced in 1993 and by 1996 was entirely defunct.

🔗 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.

🔗 Spaceflight

The Nuclear Engine for Rocket Vehicle Application (NERVA) was a nuclear thermal rocket engine development program that ran for roughly two decades. Its principal objective was to "establish a technology base for nuclear rocket engine systems to be utilized in the design and development of propulsion systems for space mission application". It was a joint effort of the Atomic Energy Commission (AEC) and the National Aeronautics and Space Administration (NASA), and was managed by the Space Nuclear Propulsion Office (SNPO) until the program ended in January 1973. SNPO was led by NASA's Harold Finger and AEC's Milton Klein.

NERVA had its origins in Project Rover, an AEC research project at the Los Alamos Scientific Laboratory (LASL) with the initial aim of providing a nuclear-powered upper stage for the United States Air Force intercontinental ballistic missiles. Nuclear thermal rocket engines promised to be more efficient than chemical ones. After the formation of NASA in 1958, Project Rover was continued as a civilian project and was reoriented to producing a nuclear powered upper stage for NASA's Saturn V Moon rocket. Reactors were tested at very low power before being shipped to Jackass Flats in the Nevada Test Site. While LASL concentrated on reactor development, NASA built and tested complete rocket engines.

The AEC, SNPO, and NASA considered NERVA a highly successful program in that it met or exceeded its program goals. It demonstrated that nuclear thermal rocket engines were a feasible and reliable tool for space exploration, and at the end of 1968 SNPO deemed that the latest NERVA engine, the XE, met the requirements for a human mission to Mars. It had strong political support from Senators Clinton P. Anderson and Margaret Chase Smith but was cancelled by President Richard Nixon in 1973. Although NERVA engines were built and tested as much as possible with flight-certified components and the engine was deemed ready for integration into a spacecraft, they never flew in space.