Random Articles (Page 255)
Have a deep view into what people are curious about.
π Alan L. Hart
Alan L. Hart (born Alberta Lucille Hart, October 4, 1890Β β July 1, 1962) was an American physician, radiologist, tuberculosis researcher, writer and novelist. He was in 1917β18 one of the first trans men to undergo hysterectomy in the United States, and lived the rest of his life as a man. He pioneered the use of x-ray photography in tuberculosis detection, and helped implement TB screening programs that saved thousands of lives.
Discussed on
- "Alan L. Hart" | 2020-05-02 | 43 Upvotes 2 Comments
π Peirce Quincuncial Projection
The Peirce quincuncial projection is a conformal map projection developed by Charles Sanders Peirce in 1879. The projection has the distinctive property that it can be tiled ad infinitum on the plane, with edge-crossings being completely smooth except for four singular points per tile. The projection has seen use in digital photography for portraying 360Β° views. The description quincuncial refers to the arrangement of four quadrants of the globe around the center hemisphere in an overall square pattern. Typically the projection is oriented such that the north pole lies at the center.
Discussed on
- "Peirce Quincuncial Projection" | 2021-07-01 | 26 Upvotes 2 Comments
π US Gold Reserve Act
The United States Gold Reserve Act of January 30, 1934 required that all gold and gold certificates held by the Federal Reserve be surrendered and vested in the sole title of the United States Department of the Treasury. It also prohibited the Treasury and financial institutions from redeeming dollar bills for gold, established the Exchange Stabilization Fund under control of the Treasury to control the dollarβs value without the assistance (or approval) of the Federal Reserve, and authorized the president to establish the gold value of the dollar by proclamation.
Immediately following passage of the Act, the President, Franklin D. Roosevelt, changed the statutory price of gold from $20.67 per troy ounce to $35. This price change incentivized gold miners globally to expand production and foreigners to export their gold to the United States, while simultaneously devaluing the U.S. dollar by increasing inflation. The increase in gold reserves due to the price change resulted in a large accumulation of gold in the Federal Reserve and U.S. Treasury, much of which was stored in the United States Bullion Depository at Fort Knox and other locations. The increase in gold reserves increased the money supply, lowering real interest rates which in turn increased investment in durable goods.
A year earlier, in 1933, Executive Order 6102 had made it a criminal offense for U.S. citizens to own or trade gold anywhere in the world, with exceptions for some jewelry and collector's coins. These prohibitions were relaxed starting in 1964 β gold certificates were again allowed for private investors on April 24, 1964, although the obligation to pay the certificate holder on demand in gold specie would not be honored. By 1975 Americans could again freely own and trade gold.
Discussed on
- "US Gold Reserve Act" | 2021-10-05 | 15 Upvotes 39 Comments
π Confocal microscopy
Confocal microscopy, most frequently confocal laser scanning microscopy (CLSM) or laser scanning confocal microscopy (LSCM), is an optical imaging technique for increasing optical resolution and contrast of a micrograph by means of using a spatial pinhole to block out-of-focus light in image formation. Capturing multiple two-dimensional images at different depths in a sample enables the reconstruction of three-dimensional structures (a process known as optical sectioning) within an object. This technique is used extensively in the scientific and industrial communities and typical applications are in life sciences, semiconductor inspection and materials science.
Light travels through the sample under a conventional microscope as far into the specimen as it can penetrate, while a confocal microscope only focuses a smaller beam of light at one narrow depth level at a time. The CLSM achieves a controlled and highly limited depth of field.
Discussed on
- "Confocal microscopy" | 2024-01-22 | 44 Upvotes 19 Comments
π Xinjiang Re-Education Camps
The Xinjiang re-education camps, officially called Vocational Education and Training Centers by the government of the People's Republic of China, are internment camps that have been operated by the Xinjiang Uygur Autonomous Region government for the purpose of indoctrinating Uyghurs since 2017 as part of a "people's war on terror" announced in 2014. The camps were established under General Secretary Xi Jinping's administration and led by party secretary, Chen Quanguo. These camps are reportedly operated outside the legal system; many Uyghurs have reportedly been interned without trial and no charges have been levied against them. Local authorities are reportedly holding hundreds of thousands of Uyghurs in these camps as well as other ethnic minority groups, for the stated purpose of countering extremism and terrorism and promoting sinicization.
As of 2018, it was estimated that the Chinese authorities may have detained hundreds of thousands, perhaps a million, Uyghurs, Kazakhs, Kyrgyz and other ethnic Turkic Muslims, Christians as well as some foreign citizens such as Kazakhstanis, who are being held in these secretive internment camps which are located throughout the region. In May 2018, Randall Schriver of the United States Department of Defense claimed that "at least a million but likely closer to three million citizens" were imprisoned in detention centers in a strong condemnation of the "concentration camps". In August 2018, a United Nations human rights panel said that it had received many credible reports that 1 million ethnic Uyghurs in China have been held in "re-education camps". There have also been multiple reports from media, politicians and researchers comparing the camps to the Chinese Cultural Revolution.
In 2019, the United Nations ambassadors from 22 nations, including Australia, Canada, France, Germany, Japan, and the United Kingdom signed a letter condemning China's mass detention of the Uyghurs and other minority groups, urging the Chinese government to close the camps. Conversely, a joint statement was signed by 37 states commending China's counter-terrorism program in Xinjiang, including Algeria, the DR Congo, Russia, Saudi Arabia, Syria, Iran, Iraq, Pakistan, North Korea, Egypt, Nigeria, the Philippines and Sudan.
Discussed on
- "Xinjiang Re-Education Camps" | 2019-10-03 | 46 Upvotes 24 Comments
π Apollo 11 missing tapes
The Apollo 11 missing tapes were those that were recorded from Apollo 11's slow-scan television (SSTV) telecast in its raw format on telemetry data tape at the time of the first Moon landing in 1969 and subsequently lost. The data tapes were recorded as a backup in case the live television broadcasts failed for any reason.
To broadcast the SSTV transmission on standard television, NASA ground receiving stations performed real-time scan conversion to the NTSC television format. The moonwalk's converted video signal was broadcast live around the world on July 21, 1969 (2:56 UTC). At the time, the NTSC broadcast was recorded on many videotapes and kinescope films. Many of these low-quality recordings remain intact. As the real-time broadcast worked and was widely recorded, preservation of the backup video was not deemed a priority in the years immediately following the mission. In the early 1980s, NASA's Landsat program was facing a severe data tape shortage and it is likely the tapes were erased and reused at this time.
A team of retired NASA employees and contractors tried to find the tapes in the early 2000s but was unable to do so. The search was sparked when several still photographs appeared in the late 1990s that showed the visually superior raw SSTV transmission on ground-station monitors. The research team conducted a multi-year investigation in the hopes of finding the most pristine and detailed video images of the moonwalk. If copies of the original SSTV format tapes were to be found, more modern digital technology could make a higher-quality conversion, yielding better images than those originally seen. The researchers concluded that the tapes containing the raw unprocessed Apollo 11 SSTV signal were erased and reused by NASA in the early 1980s, following standard procedure at the time.
Although the researchers never found the telemetry tapes, they did discover the best visual quality NTSC videotapes as well as Super 8 movie film taken of a video monitor in Australia, showing the SSTV transmission before it was converted. These visual elements were processed in 2009, as part of a NASA-approved restoration project of the first moonwalk. At a 2009 news conference in Washington, D.C., the research team released its findings regarding the tapes' disappearance. They also partially released newly enhanced footage obtained during the search. Lowry Digital completed the full moonwalk restoration project in late 2009.
π Tempest prognosticator
The tempest prognosticator, also known as the leech barometer, is a 19th-century invention by George Merryweather in which leeches are used in a barometer. The twelve leeches are kept in small bottles inside the device; when they become agitated by an approaching storm they attempt to climb out of the bottles and trigger a small hammer which strikes a bell. The likelihood of a storm is indicated by the number of times the bell is struck.
Discussed on
- "Tempest prognosticator" | 2019-09-27 | 47 Upvotes 6 Comments
π M.2
M.2, formerly known as the Next Generation Form Factor (NGFF), is a specification for internally mounted computer expansion cards and associated connectors. M.2 replaces the mSATA standard, which uses the PCI Express Mini Card physical card layout and connectors. Employing a more flexible physical specification, the M.2 allows different module widths and lengths, and, paired with the availability of more advanced interfacing features, makes the M.2 more suitable than mSATA in general for solid-state storage applications, and particularly in smaller devices such as ultrabooks and tablets.
Computer bus interfaces provided through the M.2 connector are PCI ExpressΒ 3.0 (up to four lanes), Serial ATAΒ 3.0, and USBΒ 3.0 (a single logical port for each of the latter two). It is up to the manufacturer of the M.2 host or module to select which interfaces are to be supported, depending on the desired level of host support and device type. The M.2 connector keying notches denote various purposes and capabilities of both M.2 hosts and devices. The unique key notches of M.2 modules also prevent them from being inserted into incompatible host connectors.
The M.2 specification supports NVM Express (NVMe) as the logical device interface for M.2 PCI Express SSDs, in addition to supporting legacy Advanced Host Controller Interface (AHCI) at the logical interface level. While the support for AHCI ensures software-level backward compatibility with legacy SATA devices and legacy operating systems, NVM Express is designed to fully utilize the capability of high-speed PCI Express storage devices to perform many I/O operations in parallel.
Discussed on
- "M.2" | 2018-06-03 | 17 Upvotes 4 Comments
π Atari STacy (1989)
The STacy is a portable computer version of the Atari ST.
The computer was originally designed to operate on 12 standard C cell flashlight batteries for portability. When Atari realized how quickly the machine would use up a set of batteries (especially when rechargeable batteries of the time supplied insufficient power compared to the intended alkalines), they simply glued the lid of the battery compartment shut.
The STacy has features similar to the Macintosh Portable, a version of Apple's Macintosh computer which contained a built in keyboard and monitor.
With built-in MIDI, the STacy enjoyed success for running music-sequencer software and as a controller of musical instruments among both amateurs and well-known musicians.
Discussed on
- "Atari STacy (1989)" | 2023-07-17 | 31 Upvotes 12 Comments
π Nikon F-Mount
The Nikon F-mount is a type of interchangeable lens mount developed by Nikon for its 35mm format single-lens reflex cameras. The F-mount was first introduced on the Nikon F camera in 1959, and features a three-lug bayonet mount with a 44Β mm throat and a flange to focal plane distance of 46.5Β mm. The company continues, with the 2020 D6 model, to use variations of the same lens mount specification for its film and digital SLR cameras.
Discussed on
- "Nikon F-Mount" | 2021-12-28 | 33 Upvotes 78 Comments