Ozone depletion consists of two related events observed since the late 1970s: a steady lowering of about four percent in the total amount of ozone in Earth's atmosphere, a much larger springtime decrease in stratospheric ozone around Earth's polar regions. The latter phenomenon is referred to as the ozone hole. There are springtime polar tropospheric ozone depletion events in addition to these stratospheric events. In 2019, NASA announced the "ozone hole" was the smallest since it was first discovered in 1982; the main cause of ozone depletion and the ozone hole is manufactured chemicals manufactured halocarbon refrigerants, solvents and foam-blowing agents, referred to as ozone-depleting substances. These compounds are transported into the stratosphere by turbulent mixing after being emitted from the surface, mixing much faster than the molecules can settle. Once in the stratosphere, they release halogen atoms through photodissociation, which catalyze the breakdown of ozone into oxygen. Both types of ozone depletion were observed to increase.
Ozone depletion and the ozone hole have generated worldwide concern over increased cancer risks and other negative effects. The ozone layer prevents most harmful UV wavelengths of ultraviolet light from passing through the Earth's atmosphere; these wavelengths cause skin cancer and cataracts, which were projected to increase as a result of thinning ozone, as well as harming plants and animals. These concerns led to the adoption of the Montreal Protocol in 1987, which bans the production of CFCs, halons and other ozone-depleting chemicals; the ban came into effect in 1989. Ozone levels began to recover in the 2000s. Recovery is projected to continue over the next century, the ozone hole is expected to reach pre-1980 levels by around 2075; the Montreal Protocol is considered the most successful international environmental agreement to date. Three forms of oxygen are involved in the ozone-oxygen cycle: oxygen atoms, oxygen gas, ozone gas. Ozone is formed in the stratosphere when oxygen molecules photodissociate after absorbing ultraviolet photons.
This converts a single O2 into two atomic oxygen radicals. The atomic oxygen radicals combine with separate O2 molecules to create two O3 molecules; these ozone molecules absorb ultraviolet light, following which ozone splits into a molecule of O2 and an oxygen atom. The oxygen atom joins up with an oxygen molecule to regenerate ozone; this is a continuing process that terminates when an oxygen atom recombines with an ozone molecule to make two O2 molecules. O + O3 → 2 O2 The total amount of ozone in the stratosphere is determined by a balance between photochemical production and recombination. Ozone can be destroyed by a number of free radical catalysts; the dot is a notation to indicate that each species has an unpaired electron and is thus reactive. All of these have both man-made sources; these elements are found in stable organic compounds chlorofluorocarbons, which can travel to the stratosphere without being destroyed in the troposphere due to their low reactivity. Once in the stratosphere, the Cl and Br atoms are released from the parent compounds by the action of ultraviolet light, e.g. CFCl3 + electromagnetic radiation → Cl· + ·CFCl2 Ozone is a reactive molecule that reduces to the more stable oxygen form with the assistance of a catalyst.
Cl and Br atoms destroy ozone molecules through a variety of catalytic cycles. In the simplest example of such a cycle, a chlorine atom reacts with an ozone molecule, taking an oxygen atom to form chlorine monoxide and leaving an oxygen molecule; the ClO can react with a second molecule of ozone, releasing the chlorine atom and yielding two molecules of oxygen. The chemical shorthand for these gas-phase reactions is: Cl· + O3 → ClO + O2 A chlorine atom removes an oxygen atom from an ozone molecule to make a ClO molecule ClO + O3 → Cl· + 2 O2 This ClO can remove an oxygen atom from another ozone molecule. More complicated mechanisms have been discovered that lead to ozone destruction in the lower stratosphere. A single chlorine atom would continuously destroy ozone for up to two years were it not for reactions that remove them from this cycle by forming reservoir species such as hydrogen chloride and chlorine nitrate. Bromine is more efficient than chlorine at destroying ozone on a per atom basis, but there is much less bromine in the atmosphere at present.
Both chlorine and bromine contribute to overall ozone depletion. Laboratory studies have shown that fluorine and iodine atoms participate in analogous catalytic cycles. However, fluorine atoms react with water and methane to form bound HF in the Earth's stratosphere, while organic molecules containing iodine react so in the lower atmosphere that they do not reach the stratosphere in significant quantities. A single chlorine atom is able to react with an average of 100,000 ozone molecules before it
Maja Komorowska-Tyszkiewicz is a Polish film actress. She has appeared in over 35 films since 1970. Family Life A Woman's Decision Budapest Tales Spiral The Maids of Wilko A Year of the Quiet Sun Decalogue I Inventory A Tale of Adam Mickiewicz's'Forefathers' Eve' At Full Gallop Katyń Gold Cross of Merit Grand Cross of the Order of Polonia Restituta Silver Medal of Merit for National Defence Gold Medal for Merit to Culture Gloria Artis - Award of the Minister of Culture and National Heritage in the theatre Maja Komorowska on IMDb
The Macau national basketball team is the national basketball team in Macau and run by the Macau - China Basketball Association. They have not appeared in the FIBA World Championship, but have made two appearances in the FIBA Asia Championship. Roster at the FIBA Asia Cup 2021 Pre-Qualifiers: Roster at the 2017 EABA Championship: Roster at the 2014 Lusophony Games: Team in 2013: Li Jin – 2012-2013 Sports in Macau Macau national under-19 basketball team Macau national under-17 basketball team Macau national 3x3 team Macau women's national basketball team Macau-China Basketball Association Macau Basketball Records at FIBA Archive Asia-Basket.com – Macau Men National Team
In geometry, the truncated order-6 square tiling is a uniform tiling of the hyperbolic plane. It has Schläfli symbol of t; the dual tiling represents the fundamental domains of the *443 orbifold symmetry. There are two reflective subgroup kaleidoscopic constructed from by removing one or two of three mirrors. In these images fundamental domains are alternately colored black and cyan, mirrors exist on the boundaries between colors. A larger subgroup is constructed, index 6, as with gyration points removed, becomes; the symmetry can be doubled as 642 symmetry by adding a mirror bisecting the fundamental domain. From a Wythoff construction there are eight hyperbolic uniform tilings that can be based from the regular order-4 hexagonal tiling. Drawing the tiles colored as red on the original faces, yellow at the original vertices, blue along the original edges, there are 8 forms, it can be generated from the hyperbolic tilings: Square tiling Tilings of regular polygons List of uniform planar tilings List of regular polytopes John H. Conway, Heidi Burgiel, Chaim Goodman-Strass, The Symmetries of Things 2008, ISBN 978-1-56881-220-5 "Chapter 10: Regular honeycombs in hyperbolic space".
The Beauty of Geometry: Twelve Essays. Dover Publications. 1999. ISBN 0-486-40919-8. LCCN 99035678. Weisstein, Eric W. "Hyperbolic tiling". MathWorld. Weisstein, Eric W. "Poincaré hyperbolic disk". MathWorld. Hyperbolic and Spherical Tiling Gallery KaleidoTile 3: Educational software to create spherical and hyperbolic tilings Hyperbolic Planar Tessellations, Don Hatch
The 1990 Intercontinental Final was the sixteenth running of the Intercontinental Final as part of the qualification for the 1990 Speedway World Championship. The 1990 Final was run on 12 August at the Hele Fyns Speedway Center in Fjelsted and was the last qualifying stage for riders from Scandinavia, the USA and from the Commonwealth nations for the World Final to be held at the Odsal Stadium in Bradford, England. 12 August Fjelsted, Hele Fyns Speedway Center Qualification: Top 11 plus 1 reserve to the World Final in Bradford, England* Richard Knight replaced the injured Simon Cross Motorcycle Speedway
Maytown was the main township on the Palmer River goldfields in Far North Queensland, Australia. It is now a ghost town within locality of Palmer in the Shire of Cook, having been active from c. 1874 to the 1920s. It was added to the Queensland Heritage Register on 1 June 2004. Kuku Yalanji is an Australian Aboriginal language of the Mossman and Daintree areas of North Queensland; the language region includes areas within the local government area of Shire of Douglas and Shire of Cook the localities of Mossman, Bloomfield River, China Camp, Palmer, Cape Tribulation and Wujal Wujal. Yalanji is an Australian Aboriginal language of Far North Queensland; the traditional language region is Mossman River in the south to the Annan River in the north, bordered by the Pacific Ocean in the east and extending inland to west of Mount Mulgrave. This includes the local government boundaries of the Shire of Douglas, the Shire of Cook and the Aboriginal Shire of Wujal Wujal and the towns and localities of Cooktown, Daintree, Cape Tribulation and Wujal Wujal.
It includes the head of the Palmer River, the Bloomfield River, China Camp and Palmerville. After James Venture Mulligan's discovery of gold on the Palmer River in August 1873, a rush followed and was sustained for several years by further alluvial finds. An estimated twenty to thirty thousand people made their way to the field or Cooktown in the early years, it was regarded as an ideal "small man's field" for diggers without capital and experience had the opportunity to get rich quickly. The alluvial mining communities tended to concentrate in ephemeral canvas camps; the most substantial were Palmerville, on the eastern edges of Kokomini territory and Byerstown, whose establishment reflected an eastward movement of the mining population along the river. In May 1875 Maytown became the administrative and business centre of the field. Called Edwardstown after the local butcher, John Edwards, the town was surveyed in 1875 by Archibald Campbell MacMillan, it has been claimed. In 1876 there were 12 hotels, 6 stores, 3 bakers, 3 tobacconists and stationers, Edwards the butcher, lemonade factory and a surgeon.
The sheer size of the population, estimated in May 1877 at 19,500 for the field, kept money circulating among commercial houses for essentials and luxury goods, but at the same time, there was little financial investment in the permanent manifestations of settlement. By 1882 the number of hotels had declined to six, there were two European Stores, 10 Chinese stores, two banks, two butchers, blacksmith, chemist, lemonade factory and printer. A post office existed from 1876 to 1945. By 1877, the Golden Age newspaper was printed followed by the Palmer Chronicle in 1883. Mining Warden Philip Frederic Sellheim, an educated family man residing at Maytown, bemoaned the lack of social institutions and initiated the establishment of a hospital and Miners' Institute Library, although these did not eventuate until the 1880s when most of Maytown's population had departed. In 1886 the population was 450 Chinese. There was no Christian church. By the turn of the century the town had a branch of the Queensland Government Savings Bank, a state school, school of arts, police barracks, one hotel, eight stores - four of which were Chinese, a baker and Miners Institute.
In 1900, the town had a population of 674. By 1924 only Wah Chong and Company's store remained operating. Buildings like the school, which closed in 1925, remained abandoned until World War II in the hope of a mining revival; the town was abandoned by 1945. Today there are only the remains of the baker's oven, stone kerb and channeling along the former Leslie Street, telegraph poles, floor paving, a cemetery with 16 headstones from 1875 to 1986 remaining and in Duff Street a replica hut built by the Palmer River Historical Preservation Society; the township is located on the north bank of the Palmer River near the junction of Butcher's Creek. The area contains a high concentration of building footings; some street alignments are discernible and one street contains laid stone kerbing and gutters. Dominant structural remains include a brick baker's oven, timber uprights for the school, a Chinese temple site, burnt timber stumps and corrugated iron sheets of the police station. A stone commemorative cairn and an replica of a miner's hut have been constructed in the centre of the town site.
The cemetery contains about 40 identifiable graves including 16 with headstones. The earliest headstone is dated 1875; the latest headstone is dated 1986 marking Sam Elliott's grave. There is no surviving plant. Maytown Township was listed on the Queensland Heritage Register on 1 June 2004 having satisfied the following criteria; the place is important in demonstrating the pattern of Queensland's history. Maytown Township is significant as the major settlement on the Palmer goldfield. Founded beyond the frontier of pastoral occupation, it became an important centre for administration and cultural contact with local Aboriginal people and Chinese miners; the town site contains building footings associated with commerce. The place demonstrates uncommon or endangered aspects of Queensland's cultural heritage; the presence of stone kerb and channelling is rare on far northern gold