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Chrism
Chrism, also called myrrh, myron, holy anointing oil, and consecrated oil, is a consecrated oil used in the Anglican, Armenian, Assyrian, Catholic and Old Catholic, Eastern and Oriental Orthodox, and Nordic Lutheran Churches in the administration of certain sacraments and ecclesiastical functions.
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  • 23 Nov 2022
Topic Review
Reggiane Re.2000
The Reggiane Re 2000 Falco I was an Italian all metal, low-wing monoplane developed and manufactured by aircraft company Reggiane. The type was used extensively by the Regia Aeronautica (Italian Air Force) and the Swedish Air Force during the first part of the Second World War. The Re 2000 was developed by a team headed by aircraft designers Roberto Longhi and Antonio Alessio to be a lightly-built and highly maneuverable interceptor/fighter aircraft. The emergent design, which had been designated as the Re 2000 Falco I, was equipped with a Curtiss-Wright-style retractable undercarriage, bore substantial similarities to the American-built Seversky P-35. On 24 May 1939, the prototype performed its maiden flight. Flight testing of the prototype revealed it to be able to outfight several significant combat aircraft of the time, including even the more modern Macchi C 200 and the German Messerschmitt Bf 109E fighters. During the run up to and following the outbreak of the Second World War, the aircraft was ordered by several nations, including the Hungarian, Swedish, United Kingdom and Italian governments. Upon entering squadron service, the Re 2000 soon proved to be a technically advanced aircraft, being well balanced and extremely aerodynamic during flight, but was not without its faults. Although the aircraft was potentially superior to Italian contemporary fighters (Fiat G 50 and Macchi C 200), the Re 2000 was not considered to be satisfactory by Italian military authorities. Consequently, the manufacturer built the type for export and almost all of the first production served with the Swedish Air Force and Hungarian Air Force , rather than in the Regia Aeronautica. The Re.2000 served as the starting point for several derivatives, including the MÁVAG Héja, Reggiane Re.2001, Re.2002, Re.2003, Re.2004, Re.2005, Re.2006 and Re.2007 combat aircraft.
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  • 23 Nov 2022
Topic Review
Active Pixel Sensor
An active-pixel sensor (APS) is an image sensor where each picture element ("pixel") has a photodetector and an active amplifier. There are many types of integrated circuit active pixel sensors including the complementary metal–oxide–semiconductor (CMOS) APS used most commonly in cell phone cameras, web cameras, most digital pocket cameras since 2010, in most digital single-lens reflex cameras (DSLRs) and Mirrorless interchangeable-lens cameras (MILCs). Such an image sensor is produced using CMOS technology (and is hence also known as a CMOS sensor), and has emerged as an alternative to charge-coupled device (CCD) image sensors. The term 'active pixel sensor' is also used to refer to the individual pixel sensor itself, as opposed to the image sensor; in that case the image sensor is sometimes called an active pixel sensor imager, or active-pixel image sensor.
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  • 23 Nov 2022
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HMS Lady Nelson (1798)
His Majesty's Armed Survey Vessel Lady Nelson was commissioned in 1799 to survey the coast of Australia. At the time large parts of the Australian coast were unmapped and Britain had claimed only part of the continent. The British Government were concerned that, in the event of settlers of another European power becoming established in Australia, any future conflict in Europe would lead to a widening of the conflict into the southern hemisphere to the detriment of the trade that Britain sought to develop. It was against this background that Lady Nelson was chosen to survey and establish sovereignty over strategic parts of the continent. Lady Nelson left Portsmouth on 18 March 1800 and arrived at Sydney on 16 December 1800 after having been the first vessel to reach the east coast of Australia via Bass Strait. Prior to that date all vessels had sailed around the southern tip of Tasmania to reach their destination. Lady Nelson's survey work commenced shortly after her arrival at Sydney, initially in the Bass Strait area. She was involved in the discovery of Port Phillip, on the coast of Victoria, in establishing settlements on the River Derwent and at Port Dalrymple in Tasmania, at Newcastle and Port Macquarie in New South Wales, and on Melville Island off the north coast of the continent.
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  • 23 Nov 2022
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Song of Ascents
Song of Ascents is a title given to fifteen of the Psalms, 120–134 (119–133 in the Septuagint and the Vulgate), each starting with the superscription Shir Hama'aloth (שיר המעלות šîr ha-ma‘ălōṯ, meaning "Song of the Ascents"), or, in the case of Psalm 121, Shir Lama'aloth (שיר למעלות šîr la-ma‘ălōṯ, "a song regarding ascents"). They are also variously called Gradual Psalms, Fifteen Psalms, Songs of Degrees, Songs of Steps, songs for going up to worship or Pilgrim Songs. Four of them (Psalms 122, 124, 131, and 133) are linked in their ascriptions to David, and one (127) to Solomon. Three of them (Psalms 131, 133, and 134) have only three verses. The longest is Psalm 132 (18 verses).
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  • 23 Nov 2022
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Variable-Pitch Propeller
A variable-pitch propeller or controllable-pitch propeller (CPP) is a type of propeller with blades that can be rotated around their long axis to change the blade pitch. Reversible propellers—those where the pitch can be set to negative values—can also create reverse thrust for braking or going backwards without the need to change the direction of shaft revolution.
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  • 23 Nov 2022
Topic Review
Sultan
Sultan (/ˈsʌltən/; Arabic: سلطان sulṭān, pronounced [sʊlˈtˤɑːn, solˈtˤɑːn]) is a position with several historical meanings. Originally, it was an Arabic abstract noun meaning "strength", "authority", "rulership", derived from the verbal noun سلطة sulṭah, meaning "authority" or "power". Later, it came to be used as the title of certain rulers who claimed almost full sovereignty in practical terms (i.e., the lack of dependence on any higher ruler), albeit without claiming the overall caliphate, or to refer to a powerful governor of a province within the caliphate. The adjectival form of the word is "sultanic", and the state and territories ruled by a sultan, as well as his office, are referred to as a sultanate (سلطنة salṭanah). The term is distinct from king (ملك malik), despite both referring to a sovereign ruler. The use of "sultan" is restricted to Muslim countries, where the title carries religious significance, contrasting the more secular king, which is used in both Muslim and non-Muslim countries. Brunei and Oman are the only independent countries which retain the title "sultan" for their monarchs. In recent years, the title has been gradually replaced by "king" by contemporary hereditary rulers who wish to emphasize their secular authority under the rule of law. A notable example is Morocco, whose monarch changed his title from sultan to king in 1957.
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Transposon
Transposons are sequences of DNA that can move around to different positions within the genome of a single cell, a process called transposition. In the process, they can cause mutations and change the amount of DNA in the genome. Transposons are also called "jumping genes" or "mobile genetic elements". Discovered by Barbara McClintock early in her career, the topic went on to be a Nobel winning work in 1983. There are a variety of mobile genetic elements, and they can be grouped based on their mechanism of transposition. Class I mobile genetic elements, or retrotransposons, move in the genome by being transcribed to RNA and then back to DNA by reverse transcriptase, while class II mobile genetic elements move directly from one position to another within the genome using a transposase to "cut and paste" them within the genome. Transposons are very useful to researchers as a means to alter DNA inside of a living organism. Transposons make up a large fraction of genome sizes which is evident through the C-values of eukaryotic species. As an example about 45% of the human genome is composed of transposons and their defunct remnants.
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Marasuchus
Marasuchus (meaning "Mara crocodile") is a genus of basal dinosauriform archosaur which is possibly synonymous with Lagosuchus. Both genera lived during the Late Triassic in what is now La Rioja Province, Argentina . Marasuchus contains a single species, Marasuchus lilloensis. Marasuchus lilloensis was originally designated as Lagosuchus lilloensis in 1972. It was considered a new species of Lagosuchus, a contemporary archosaur described the previous year. However, a 1994 study argued that the original material of Lagosuchus was undiagnostic. This would mean that Lagosuchus and its original species (Lagosuchus talampayaensis) could be considered nomen dubia. Specimens of Lagosuchus stored at a museum in San Miguel de Tucuman were considered to be more diagnostic than those of L. talampayensis, and thus they were given a new genus: Marasuchus. A 2019 study redescribed the original material of Lagosuchus and concluded that it was valid and not readily distinguishable from Marasuchus lilloensis. This suggests that Marasuchus lilloensis is a junior synonym of Lagosuchus talampayensis. Specimens referred to the genus Marasuchus possessed some, but not all of the adaptations which traditionally characterized dinosaurs. For example, its proportions indicate that it was likely bipedal as in early dinosaurs. Also, it shared certain specific characteristics with that group, most relating to the hip and the head of the femur. Nevertheless, it lacked certain dinosaur-like features such as a perforated acetabulum, and it had several plesiomorphic ("primitive") features of the ankle.
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  • 23 Nov 2022
Topic Review
Lunar Outpost (NASA)
A lunar outpost is a concept of a permanent or semi-permanent presence of humans on the Moon, a moonbase, by the United States space administration NASA. NASA requested an increase in the 2020 budget of $1.6 billion, in order to make another crewed mission to the Moon by 2025 (originally 2024), followed by a sustained presence on the Moon by 2028.
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  • 23 Nov 2022
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