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Topic Review
Cairn
A cairn is a man-made pile (or stack) of stones. The word cairn comes from the Scottish Gaelic: càrn [ˈkʰaːrˠn̪ˠ] (plural càirn [ˈkʰaːrˠɲ]). Cairns have been and are used for a broad variety of purposes, from prehistoric times to the present. In modern times, cairns are often erected as landmarks, a use they have had since ancient times. However, since prehistory, they have also been built and used as burial monuments; for defense and hunting; for ceremonial purposes, sometimes relating to astronomy; to locate buried items, such as caches of food or objects; and to mark trails, among other purposes. Cairns are used as trail markers in many parts of the world, in uplands, on moorland, on mountaintops, near waterways and on sea cliffs, as well as in barren deserts and tundras. They vary in size from small stone markers to entire artificial hills, and in complexity from loose conical rock piles to delicately balanced sculptures and elaborate feats of megalithic engineering. Cairns may be painted or otherwise decorated, whether for increased visibility or for religious reasons. An ancient example is the inuksuk (plural inuksuit), used by the Inuit, Inupiat, Kalaallit, Yupik, and other peoples of the Arctic region of North America. Inuksuit are found from Alaska to Greenland. This region, above the Arctic Circle, is dominated by the tundra biome and has areas with few natural landmarks.
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  • 30 Nov 2022
Topic Review
Global Warming Policy Foundation
The Global Warming Policy Foundation (GWPF) is a lobby group in the United Kingdom whose stated aims are to challenge "extremely damaging and harmful policies" envisaged by governments to mitigate anthropogenic global warming. While their position is that the science of global warming or climate change is "not yet settled," the GWPF claims that its membership comes from a broad spectrum ranging from "the IPCC position through agnosticism to outright scepticism." The GWPF as well as some of its prominent members have been characterized as promoting climate change denial. In 2014, when the Charity Commission ruled that the GWPF had breached rules on impartiality, a non-charitable organisation called the "Global Warming Policy Forum" was created as a wholly owned subsidiary, to do lobbying that a charity could not. The GWPF website carries an array of articles "sceptical" of scientific findings of anthropogenic global warming and its impacts.
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Topic Review
Sulphur Mountain Formation
The Sulphur Mountain Formation is a geologic formation of Early to Middle Triassic age. It is present on the western edge of the Western Canada Sedimentary Basin in the foothills and Rocky Mountains of western Alberta and northeastern British Columbia. It includes marine fossils from the time shortly after the Permian-Triassic extinction event. The Sulphur Mountain Formation was first described as a member of the Spray River Formation by P.S. Warren in 1945, who named it for Sulphur Mountain in Banff National Park. It was later raised to formation status. Its type section is located in the Spray River gorge at the southern end of Sulphur Mountain.
  • 544
  • 30 Nov 2022
Topic Review
Carbon-Based Nanomaterials Biodegradation
Carbon-based nanomaterials (CNMs) have attracted a growing interest over the last decades. They have become a material commonly used in industry, consumer products, water purification, and medicine. The knowledge about the biodegradation of nanomaterials will facilitate the development of the principals of “biodegradable-by-design” nanoparticles which have promising application in medicine as nano-carriers and represent lower toxicity and risks for living species and the environment.
  • 450
  • 30 Nov 2022
Topic Review
Artificial Intelligence in Archaeology
Artificial Intelligence (AI), due to its increasingly powerful predictive capabilities, is showing an increasing trend in attracting widespread interest in many sciences. Archaeologists now can more fully exploit the knowledge from an extensive amount of archaeological data with the use of artificial intelligence in such a way as to make decisions related to appropriate strategies for the preservation and protection of archaeological elements, as well as to decide on the most ideal point excavation in a complex cultural landscape. 
  • 4.5K
  • 30 Nov 2022
Topic Review
Energy Transitions Commission
The Energy Transition Commission (ETC) is an international think tank, focusing on economic growth and climate change mitigation. It was created in September 2015 and is based in London. The commission currently contains 32 commissioners from a selection of individuals and company and government leaders.
  • 519
  • 29 Nov 2022
Topic Review
Deforestation and Global Warming
Deforestation is a primary contributor to climate change. Land use changes, especially in the form of deforestation, are the second largest anthropogenic source of atmospheric carbon dioxide emissions, after fossil fuel combustion. Greenhouse gases are emitted during combustion of forest biomass and decomposition of remaining plant material and soil carbon. Global models and national greenhouse gas inventories give similar results for deforestation emissions. Although deforestation and peatland degradation are only about 10% of global carbon dioxide emissions (As of 2019), growing forests are also a carbon sink with additional potential to mitigate the effects of climate change. Some of the effects of climate change, such as more wildfires, may increase deforestation. Deforestation comes in many forms: wildfire, agricultural clearcutting, livestock ranching, and logging for timber, among others. The vast majority of agricultural activity resulting in deforestation is subsidized by government tax revenue. Forests cover 31% of the land area on Earth and annually 75,700 square kilometers (18.7 million acres) of the forest is lost. Mass deforestation continues to threaten tropical forests, their biodiversity and the ecosystem services they provide. The main area of concern of deforestation is in tropical rain forests since they are home to the majority of the planet's biodiversity.
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  • 29 Nov 2022
Topic Review
Scientific Opinion on Climate Change
Scientific opinion on climate change is a judgment of scientists regarding the degree to which global warming is occurring, its likely causes, and its probable consequences. A related—but not identical—term, "scientific consensus on climate change," is the prevailing view on climate change within the scientific community. The consensus is that:
  • 1.1K
  • 29 Nov 2022
Topic Review
Temperature Record of the Past 1000 Years
The temperature record of the past 1,000 years or longer is reconstructed using data from climate proxy records in conjunction with the modern instrumental temperature record which only covers the last 170 years at a global scale. Large-scale reconstructions covering part or all of the 1st millennium and 2nd millennium have shown that recent temperatures are exceptional: the Intergovernmental Panel on Climate Change Fourth Assessment Report of 2007 concluded that "Average Northern Hemisphere temperatures during the second half of the 20th century were very likely higher than during any other 50-year period in the last 500 years and likely the highest in at least the past 1,300 years." The curve shown in graphs of these reconstructions is widely known as the hockey stick graph because of the sharp increase in temperatures during the last century. As of 2010 this broad pattern was supported by more than two dozen reconstructions, using various statistical methods and combinations of proxy records, with variations in how flat the pre-20th-century "shaft" appears. Sparseness of proxy records results in considerable uncertainty for earlier periods. Individual proxy records, such as tree ring widths and densities used in dendroclimatology, are calibrated against the instrumental record for the period of overlap. Networks of such records are used to reconstruct past temperatures for regions: tree ring proxies have been used to reconstruct Northern Hemisphere extratropical temperatures (within the tropics trees do not form rings) but are confined to land areas and are scarce in the Southern Hemisphere which is largely ocean. Wider coverage is provided by multiproxy reconstructions, incorporating proxies such as lake sediments, ice cores and corals which are found in different regions, and using statistical methods to relate these sparser proxies to the greater numbers of tree ring records. The "Composite Plus Scaling" (CPS) method is widely used for large-scale multiproxy reconstructions of hemispheric or global average temperatures; this is complemented by Climate Field Reconstruction (CFR) methods which show how climate patterns have developed over large spatial areas, making the reconstruction useful for investigating natural variability and long-term oscillations as well as for comparisons with patterns produced by climate models. During the 1,900 years before the 20th century, it is likely that the next warmest period was from 950 to 1100, with peaks at different times in different regions. This has been called the Medieval Warm Period, and some evidence suggests widespread cooler conditions during a period around the 17th century known as the Little Ice Age. In the hockey stick controversy, contrarians have asserted that the Medieval Warm Period was warmer than at present, and have disputed the data and methods of climate reconstructions.
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Topic Review
Impact of High-Temperature Treatment on Granite
Temperature changes have significant effects on rock properties. The changes in properties vary for different rocks with different temperature ranges. Granite is an igneous type of rock that is common in India and is frequently used for construction and domestic purposes. Granite is mainly composed of quartz and feldspar and shows a considerable response to temperature changes. The heating effects of granite on its physical and mechanical properties become increasingly pronounced with increasing pick temperatures. 
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