Have a deep view into what people are curious about.

🔗 Writing systems 🔗 Archaeology 🔗 Romania

The Vinča symbols, sometimes known as the Danube script, Vinča signs, Vinča script, Vinča–Turdaș script, Old European script, etc., are a set of symbols found on Neolithic era (6th to 5th millennia BC) artifacts from the Vinča culture of Central Europe and Southeastern Europe. The vast majority of historians agree that those symbols are not a writing system, but private symbols or ornaments of some kind. A minority of historians claim that this is the earliest known writing system that has influenced other early writing systems.

🔗 Spaceflight

StarTram is a proposed space launch system propelled by maglev. The initial Generation 1 facility would launch cargo only, launching from a mountain peak at an altitude of 3 to 7 kilometres (1.9 to 4.3 mi) with an evacuated tube staying at local surface level; it has been claimed that about 150,000 tons could be lifted to orbit annually. More advanced technology would be required for the Generation 2 system for passengers, with a longer track instead gradually curving up at its end to the thinner air at 22 kilometres (14 mi) altitude, supported by magnetic levitation, reducing g-forces when each capsule transitions from the vacuum tube to the atmosphere. A SPESIF 2010 presentation stated that Generation 1 could be completed by the year 2020 or later if funding began in 2010, and Generation 2 by 2030 or later.

🔗 Chemicals 🔗 Plants

Cucurbitacin is a class of biochemical compounds that some plants – notably members of the pumpkin and gourd family, Cucurbitaceae – produce and which function as a defence against herbivores. Cucurbitacins are chemically classified as triterpenes, formally derived from cucurbitane, a triterpene hydrocarbon – specifically, from the unsaturated variant cucurbit-5-ene, or 19(10→9β)-abeo-10α-lanost-5-ene. They often occur as glycosides. They and their derivatives have been found in many plant families (including Brassicaceae, Cucurbitaceae, Scrophulariaceae, Begoniaceae, Elaeocarpaceae, Datiscaceae, Desfontainiaceae, Polemoniaceae, Primulaceae, Rubiaceae, Sterculiaceae, Rosaceae, and Thymelaeaceae), in some mushrooms (including Russula and Hebeloma) and even in some marine mollusks.

Cucurbitacins may be a taste deterrent in plants foraged by some animals and in some edible plants preferred by humans, like cucumbers and zucchinis. In laboratory research, cucurbitacins have cytotoxic properties and are under study for their potential biological activities.

The Ramer–Douglas–Peucker algorithm, also known as the Douglas–Peucker algorithm and iterative end-point fit algorithm, is an algorithm that decimates a curve composed of line segments to a similar curve with fewer points.

🔗 Apple Inc./Macintosh 🔗 Apple Inc. 🔗 Computing 🔗 Computing/Software

GEOS (Graphic Environment Operating System) is a discontinued operating system from Berkeley Softworks (later GeoWorks). Originally designed for the Commodore 64 with its version being released in 1986, enhanced versions of GEOS later became available in 1987 for the Commodore 128 and in 1988 for the Apple II family of computers. A lesser-known version was also released for the Commodore Plus/4.

GEOS closely resembles early versions of the classic Mac OS and includes a graphical word processor (geoWrite) and paint program (geoPaint).

A December 1987 survey by the Commodore-dedicated magazine Compute!'s Gazette found that nearly half of respondents used GEOS. For many years, Commodore bundled GEOS with its redesigned and cost-reduced C64, the C64C. At its peak, GEOS was the third-most-popular microcomputer operating system in the world in terms of units shipped, trailing only MS-DOS and Mac OS (besides the original Commodore 64's KERNAL).

Other GEOS-compatible software packages were available from Berkeley Softworks or from third parties, including a reasonably sophisticated desktop publishing application called geoPublish and a spreadsheet called geoCalc. While geoPublish is not as sophisticated as Aldus Pagemaker and geoCalc not as sophisticated as Microsoft Excel, the packages provide reasonable functionality, and Berkeley Softworks founder Brian Dougherty claimed the company ran its business using its own software on Commodore 8-bit computers for several years.

🔗 Biography 🔗 Soviet Union 🔗 Russia 🔗 Biography/sports and games 🔗 Russia/sports and games in Russia 🔗 Armenia 🔗 Underwater diving 🔗 Swimming

Shavarsh Vladimiri (Vladimirovich) Karapetyan (Armenian: Շավարշ Կարապետյան; born May 19, 1953) is a retired former Soviet finswimmer, best known for saving the lives of 20 people in a 1976 incident in Yerevan.

🔗 Computer science 🔗 Mathematics

Tupper's self-referential formula is a formula that visually represents itself when graphed at a specific location in the (x, y) plane.

🔗 Biography 🔗 California 🔗 California/San Francisco Bay Area 🔗 Apple Inc. 🔗 Biography/science and academia 🔗 LGBT studies

Ronald Wayne (born May 17, 1934) is a retired American electronics industry businessman. He co-founded Apple Computer Company (now Apple Inc.) as a partnership with Steve Wozniak and Steve Jobs, providing administrative oversight and documentation for the new venture. Twelve days later, he sold his 10% share of the new company back to Jobs and Wozniak for US$800, and one year later accepted a final US$1,500 to forfeit any potential future claims against the newly legally incorporated Apple, totaling $2,300.

🔗 Energy

A black start is the process of restoring an electric power station or a part of an electric grid to operation without relying on the external electric power transmission network to recover from a total or partial shutdown.

Normally, the electric power used within the plant is provided from the station's own generators. If all of the plant's main generators are shut down, station service power is provided by drawing power from the grid through the plant's transmission line. However, during a wide-area outage, off-site power from the grid is not available. In the absence of grid power, a so-called black start needs to be performed to bootstrap the power grid into operation.

To provide a black start, some power stations have small diesel generators, normally called the black start diesel generator (BSDG), which can be used to start larger generators (of several megawatts capacity), which in turn can be used to start the main power station generators. Generating plants using steam turbines require station service power of up to 10% of their capacity for boiler feedwater pumps, boiler forced-draft combustion air blowers, and for fuel preparation. It is uneconomical to provide such a large standby capacity at each station, so black-start power must be provided over designated tie lines from another station. Often hydroelectric power plants are designated as the black-start sources to restore network interconnections. A hydroelectric station needs very little initial power for starting purposes (just enough to open the intake gates and provide excitation current to the generator field coils), and can put a large block of power on line very quickly to allow start-up of fossil-fuel or nuclear stations. Certain types of combustion turbine can be configured for black start, providing another option in places without suitable hydroelectric plants. In 2017, a utility in Southern California successfully demonstrated the use of a battery-based energy-storage system to provide a black start, firing up a combined-cycle gas turbine from an idle state.