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🔗 Telecommunications

Digital mobile radio (DMR) is a limited open digital mobile radio standard defined in the European Telecommunications Standards Institute (ETSI) Standard TS 102 361 parts 1–4 and used in commercial products around the world. DMR, along with P25 phase II and NXDN are the main competitor technologies in achieving 6.25 kHz equivalent bandwidth using the proprietary AMBE+2 vocoder. DMR and P25 II both use two-slot TDMA in a 12.5 kHz channel, while NXDN uses discrete 6.25 kHz channels using frequency division and TETRA uses a four-slot TDMA in a 25 kHz channel.

DMR was designed with three tiers. DMR tiers I and II (conventional) were first published in 2005, and DMR III (Trunked version) was published in 2012, with manufacturers producing products within a few years of each publication.

The primary goal of the standard is to specify a digital system with low complexity, low cost and interoperability across brands, so radio communications purchasers are not locked into a proprietary solution. In practice, given the current limited scope of the DMR standard, many vendors have introduced proprietary features that make their product offerings non-interoperable with other brands.

🔗 International relations 🔗 Human rights 🔗 Russia 🔗 Military history 🔗 Crime 🔗 Death 🔗 Ukraine 🔗 Russia/Russian, Soviet, and CIS military history 🔗 Military history/Russian, Soviet and CIS military history

In March 2022, a series of war crimes were committed by Russian occupation forces in the Ukrainian city of Bucha during the Battle of Bucha, following the Russian invasion of Ukraine. Ukrainian authorities said that more than 300 inhabitants of the town had been killed.

🔗 Lists 🔗 Transport 🔗 Transport/Maritime

Fifty-eight selected navigational stars are given a special status in the field of celestial navigation. Of the approximately 6,000 stars visible to the naked eye under optimal conditions, the selected stars are among the brightest and span 38 constellations of the celestial sphere from the declination of −70° to +89°. Many of the selected stars were named in antiquity by the Babylonians, Greeks, Romans, and Arabs.

The star Polaris, often called the "North Star", is treated specially due to its proximity to the north celestial pole. When navigating in the Northern Hemisphere, special techniques can be used with Polaris to determine latitude or gyrocompass error. The other 57 selected stars have daily positions given in nautical almanacs, aiding the navigator in efficiently performing observations on them. A second group of 115 "tabulated stars" can also be used for celestial navigation, but are often less familiar to the navigator and require extra calculations.

For purposes of identification, the positions of navigational stars — expressed as declination and sidereal hour angle — are often rounded to the nearest degree. In addition to tables, star charts provide an aid to the navigator in identifying the navigational stars, showing constellations, relative positions, and brightness.

🔗 Religion 🔗 Central Asia 🔗 Archaeology 🔗 Visual arts 🔗 Buddhism 🔗 World Heritage Sites 🔗 Religion/Interfaith 🔗 Public Art 🔗 Afghanistan 🔗 Sculpture 🔗 Hazara

The Buddhas of Bamiyan were two 6th-century monumental statues of Vairocana Buddha and Gautama Buddha carved into the side of a cliff in the Bamyan valley of central Afghanistan, 130 kilometres (81 mi) northwest of Kabul at an elevation of 2,500 metres (8,200 ft). Carbon dating of the structural components of the Buddhas has determined that the smaller 38 m (125 ft) "Eastern Buddha" was built around 570 AD, and the larger 55 m (180 ft) "Western Buddha" was built around 618 AD.

The statues represented a later evolution of the classic blended style of Gandhara art. The statues consisted of the male Salsal ("light shines through the universe") and the (smaller) female Shamama ("Queen Mother"), as they were called by the locals. The main bodies were hewn directly from the sandstone cliffs, but details were modeled in mud mixed with straw, coated with stucco. This coating, practically all of which wore away long ago, was painted to enhance the expressions of the faces, hands, and folds of the robes; the larger one was painted carmine red and the smaller one was painted multiple colors. The lower parts of the statues' arms were constructed from the same mud-straw mix supported on wooden armatures. It is believed that the upper parts of their faces were made from great wooden masks or casts. The rows of holes that can be seen in photographs held wooden pegs that stabilized the outer stucco.

The Buddhas are surrounded by numerous caves and surfaces decorated with paintings. It is thought that the period of florescence was from the 6th to 8th century AD, until the onset of Islamic invasions. These works of art are considered as an artistic synthesis of Buddhist art and Gupta art from India, with influences from the Sasanian Empire and the Byzantine Empire, as well as the country of Tokharistan.

The statues were blown up and destroyed in March 2001 by the Taliban, on orders from leader Mullah Mohammed Omar, after the Taliban government declared that they were idols. International and local opinion strongly condemned the destruction of the Buddhas. Some Taliban sources credited Omar's decision to blow up the Buddha statues to the growing influence of Osama bin Laden.

🔗 Spaceflight 🔗 Spaceflight/Timeline of spaceflight working group

This article documents notable spaceflight events during the year 2019.

🔗 Medicine

The Krukenberg procedure, also known as the Krukenberg operation, is a surgical technique that converts a forearm stump into a pincer. It was first described in 1917 by the German army surgeon Hermann Krukenberg. It remains in use today for certain special cases but is considered controversial and some surgeons refuse to perform it.

🔗 Electronics

The term All American Five (abbreviated AA5) is a colloquial name for mass-produced, superheterodyne radio receivers that used five vacuum tubes in their design. These radio sets were designed to receive amplitude modulation (AM) broadcasts in the medium wave band, and were manufactured in the United States from the mid-1930s until the early 1960s. By eliminating a power transformer, cost of the units was kept low; the same principle was later applied to television receivers. Variations in the design for lower cost, shortwave bands, better performance or special power supplies existed, although many sets used an identical set of vacuum tubes.

🔗 Technology 🔗 Canada 🔗 Guild of Copy Editors 🔗 Engineering

A screw drive is a system used to turn a screw. At a minimum, it is a set of shaped cavities and protrusions on the screw head that allows torque to be applied to it. Usually, it also involves a mating tool, such as a screwdriver, that is used to turn it. The following heads are categorized based on commonality, with some of the less-common drives being classified as "tamper-resistant".

Most heads come in a range of sizes, typically distinguished by a number, such as "Phillips #00". These sizes do not necessarily describe a particular dimension of the drive shape, but rather are arbitrary designations.

🔗 Military history 🔗 Military history/Military science, technology, and theory 🔗 Military history/Weaponry 🔗 Cold War

Blue Peacock, renamed from Blue Bunny and originally Brown Bunny, was a British tactical nuclear weapon project in the 1950s.

The project's goal was to store a number of ten-kiloton nuclear mines in Germany, to be placed on the North German Plain and, in the event of Soviet invasion from the east, detonated by wire or an eight-day timer to:

... not only destroy facilities and installations over a large area, but ... deny occupation of the area to an enemy for an appreciable time due to contamination ...

🔗 International relations 🔗 Disaster management 🔗 Medicine 🔗 Death

A pandemic (from Greek πᾶν pan "all" and δῆμος demos "people") is a disease epidemic that has spread across a large region, for instance multiple continents, or worldwide. A widespread endemic disease with a stable number of infected people is not a pandemic. Further, flu pandemics generally exclude recurrences of seasonal flu.

Throughout history, there have been a number of pandemics of diseases such as smallpox and tuberculosis. One of the most devastating pandemics was the Black Death (also known as The Plague), which killed an estimated 75–200 million people in the 14th century. Other notable pandemics include the 1918 influenza pandemic (Spanish flu) and the 2009 flu pandemic (H1N1). Current pandemics include HIV/AIDS and the 2019 coronavirus disease, which was declared a pandemic on 11 March 2020 by the World Health Organization (WHO).