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Topic Review
Sustainability in Brazil’s Beef Industry
Since the dawn of Brazilian trade, extensive cattle farming has predominated. Brazil’s extensive pasture-based system uses pasture plants adapted to climate and soil conditions with limited use of purchased inputs. Domestic and international stakeholders have prioritized sustainable agricultural development in Brazil’s beef sector to reduce deforestation and other natural-habitat conversions.
  • 573
  • 23 Mar 2023
Topic Review
Sulfate-Reducing Microorganisms
Sulfate-reducing microorganisms (SRM) or sulfate-reducing prokaryotes (SRP) are a group composed of sulfate-reducing bacteria (SRB) and sulfate-reducing archaea (SRA), both of which can perform anaerobic respiration utilizing sulfate (SO42–) as terminal electron acceptor, reducing it to hydrogen sulfide (H2S). Therefore, these sulfidogenic microorganisms "breathe" sulfate rather than molecular oxygen (O2), which is the terminal electron acceptor reduced to water (H2O) in aerobic respiration. Most sulfate-reducing microorganisms can also reduce some other oxidized inorganic sulfur compounds, such as sulfite (SO32–), dithionite (S2O42–), thiosulfate (S2O32–), trithionate (S3O62–), tetrathionate (S4O62−), elemental sulfur (S8), and polysulfides (Sn2−). Depending on the context, "sulfate-reducing microorganisms" can be used in a broader sense (including all species that can reduce any of these sulfur compounds) or in a narrower sense (including only species that reduce sulfate, and excluding strict thiosulfate and sulfur reducers, for example). Sulfate-reducing microorganisms can be traced back to 3.5 billion years ago and are considered to be among the oldest forms of microbes, having contributed to the sulfur cycle soon after life emerged on Earth. Many organisms reduce small amounts of sulfates in order to synthesize sulfur-containing cell components; this is known as assimilatory sulfate reduction. By contrast, the sulfate-reducing microorganisms considered here reduce sulfate in large amounts to obtain energy and expel the resulting sulfide as waste; this is known as dissimilatory sulfate reduction. They use sulfate as the terminal electron acceptor of their electron transport chain. Most of them are anaerobes; however, there are examples of sulfate-reducing microorganisms that are tolerant of oxygen, and some of them can even perform aerobic respiration. No growth is observed when oxygen is used as the electron acceptor. In addition, there are sulfate-reducing microorganisms that can also reduce other electron acceptors, such as fumarate, nitrate (NO3−), nitrite (NO2−), ferric iron [Fe(III)], and dimethyl sulfoxide. In terms of electron donor, this group contains both organotrophs and lithotrophs. The organotrophs oxidize organic compounds, such as carbohydrates, organic acids (e.g., formate, lactate, acetate, propionate, and butyrate), alcohols (methanol and ethanol), aliphatic hydrocarbons (including methane), and aromatic hydrocarbons (benzene, toluene, ethylbenzene, and xylene). The lithotrophs oxidize molecular hydrogen (H2), for which they compete with methanogens and acetogens in anaerobic conditions. Some sulfate-reducing microorganisms can directly utilize metallic iron [Fe(0)] as electron donor, oxidizing it to ferrous iron [Fe(II)].
  • 1.1K
  • 04 Nov 2022
Topic Review
Stone Mountain
Stone Mountain is a quartz monzonite dome monadnock and the site of Stone Mountain Park near Stone Mountain, Georgia. At its summit, the elevation is 1,686 feet (514 m) above sea level and 825 feet (251 m) above the surrounding area. Stone Mountain is well known for not only its geology, but also the enormous rock relief on its north face, the largest bas-relief in the world. The carving depicts three Confederate figures, Jefferson Davis, Robert E. Lee and Stonewall Jackson, and has been the subject of widespread controversy. Stone Mountain was once owned by the Venable Brothers. It was purchased by the State of Georgia in 1958 "as a memorial to the Confederacy." Stone Mountain Park officially opened on April 14, 1965 – 100 years to the day after Lincoln's assassination, although the park had been in use for a few years. It is the most visited destination in the state of Georgia. Stone Mountain is more than 5 miles (8 km) in circumference at its base. The summit of the mountain can be reached by a walk-up trail on the west side of the mountain or by the Skyride aerial tram.
  • 2.3K
  • 04 Nov 2022
Topic Review
Steamboat Springs (Nevada)
Steamboat Springs is a small volcanic field of rhyolitic lava domes and flows in western Nevada, located south of Reno. There is extensive geothermal activity in the area, including numerous hot springs, steam vents, and fumaroles. The residential portions of this area, located mostly east of Steamboat Creek and south of modern-day SR 341, are now known simply as Steamboat. The state of Nevada has a Steamboat Springs Historical Marker (#198) situated along the eastern shoulder of the busy Carson–Reno Highway (US 395 Alt.), approximately 1.65 miles (2.66 km) south of the Mount Rose Junction (the intersection with SR 341 and SR 431). There were once several mineral spas operating here along Steamboat Creek, with at least one still in business called Steamboat Hot Springs Healing Center & Spa. The water from the springs contains many minerals including: calcium carbonate, magnesium, sodium sulfate, carbon dioxide, lithia, soda and silica.
  • 318
  • 24 Oct 2022
Topic Review
Stadt Huys Site
The Stadt Huys (an old Dutch spelling, meaning city hall) was the very first city hall in New York City built in 17th-century during Dutch settlement (New Amsterdam). It stopped function in 1679 due to safety. It is located at the 71 Pearl Street today. The Stadt Huys block archaeology project was the first large scale archaeological excavation in New York City in 1979-1980. At the time it was excavated, it was one of the most expensive and most productive projects of urban archeology undertaken in an American city. A lot of logistical procedures for urban archaeology had to be developed as the project evolved. Most of these procedures have become a model for performing large-scale excavations in the city.
  • 545
  • 28 Nov 2022
Topic Review
St. Mary's Islands
St. Mary's Islands, also known as Coconut Island and Thonsepar, are a set of four small islands in the Arabian Sea off the coast of Malpe in Udipi, Karnataka, India. They are known for their distinctive geological formation of columnar rhyolitic lava (pictured). Scientific studies indicate that the basalt of the St. Mary's Islands was formed by sub-aerial subvolcanic activity, because at that time Madagascar was attached to India. The rifting of Madagascar took place around 88 million years ago. Columnar rhyolite Lava here form one of the four geological monuments in Karnataka state, one of the 34 National Geological Monuments of India declared by the Geological Survey of India in 2016 for their protection, maintenance, promotion and enhancement of geotourism. The monument is considered an important site for "Geo Tourism".
  • 714
  • 14 Oct 2022
Topic Review
Spruce-fir Forests
Fir and spruce forests are greatly affected by slight fluctuations in climate. Temperature is the primary determinate for spatial patterns of fir and spruce. The two dominant trees in this type of forest are Picea engelmannii (Engelmann spruce) and Abies lasiocarpa (subalpine fir). Although thick-barked trees, such as the Pinus resinosa, frequently survive fire, the thin bark of spruce make them more vulnerable. Trees such as the Douglas fir withstand much of the fire due to the thicker bark they have. The scale of the burn mosaic during a fire, relative to species niche requirements and mobility, can have major impacts on flora and fauna dynamics.
  • 393
  • 17 Oct 2022
Topic Review
Southern European People
Southern European people are a pan-ethnic group, or multi-ethnic regional grouping, and the inhabitants of Southern Europe. South or Southern Europeans can usually trace back full or partial heritage to Greece, Italy, Spain , Portugal, as well as nations bordering with, or ethnoculturally related to, the region. As the pan-ethnic group is also culturally defined, rather than exclusively a geographical category, it often includes peoples inhabiting areas that are, at times, considered outside of the region. This can include people with heritage from Southern France, the Mediterranean islands of Corsica (also part of France ), Malta and Cyprus (geographically part of West Asia), Southeastern Europe's Albania and European Turkey. There are also descriptions of Southern Europeans which include ancestry from other nations in Southeast Europe, and countries of the South Slavs, particularly in diasporic identification. As Slavs, they are also often identified as Eastern Europeans. There is a large Southern European diaspora, with significant concentrations in the United Kingdom, North America (Southern European Americans and Canadians), and Southern European Australians in Oceania. Other subgroups of Europeans include Eastern European people and Northwestern European people.
  • 5.9K
  • 29 Sep 2022
Topic Review
Soufrière Hills Volcano
User:RMCD bot/subject notice The Soufrière Hills volcano is an active, complex stratovolcano with many lava domes forming its summit on the Caribbean island of Montserrat. Many volcanoes in the Caribbean are named Soufrière (French: "sulfur outlet"). These include La Soufrière or Soufrière Saint Vincent on the island of Saint Vincent, and La Grande Soufrière on Guadeloupe. After a long period of dormancy, the Soufrière Hills volcano became active in 1995 and has continued to erupt ever since. Its eruptions have rendered more than half of Montserrat uninhabitable, destroying the capital city, Plymouth, and causing widespread evacuations: about two thirds of the population have left the island. It is andesitic in nature, and the current pattern of activity includes periods of lava dome growth, punctuated by brief episodes of dome collapse which result in pyroclastic flows, ash venting, and explosive eruption. The volcano is monitored by the Montserrat Volcano Observatory. Volcanic gas emissions from this volcano are measured by a Multi-Component Gas Analyzer System, which detects pre-eruptive degassing of rising magmas, improving prediction of volcanic activity.
  • 295
  • 25 Oct 2022
Topic Review
Solar Storm of August 1972
The solar storms of August 1972 were a historically powerful series of solar storms with intense to extreme solar flare, solar particle event, and geomagnetic storm components in early August 1972, during solar cycle 20. The storm caused widespread electric‐ and communication‐grid disturbances through large portions of North America as well as satellite disruptions. On August 4, 1972, the storm caused the accidental detonation of numerous U.S. naval mines near Haiphong, North Vietnam. The coronal cloud's transit time from the Sun to the Earth is the fastest ever recorded.
  • 1.8K
  • 05 Dec 2022
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