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71-576: Egbertville is at the center of the Staten Island Greenbelt , with the park system's administrative offices being located there. Richmond Creek flows through a ravine, named the Egbertville Ravine after the neighborhood, as it skims the eastern base of Lighthouse Hill . The community's main thoroughfare is Rockland Avenue, which provides a shortcut between New Dorp on the East Shore and

142-609: A face-centered cubic lattice and iron cations occupying interstitial sites . Half of the Fe cations occupy tetrahedral sites while the other half, along with Fe cations, occupy octahedral sites. The unit cell consists of thirty-two   O ions and unit cell length is a = 0.839 nm. As a member of the inverse spinel group, magnetite can form solid solutions with similarly structured minerals, including ulvospinel ( Fe 2 TiO 4 ) and magnesioferrite ( MgFe 2 O 4 ). Titanomagnetite, also known as titaniferous magnetite,

213-493: A mineral and one of the main iron ores , with the chemical formula Fe Fe 3+ 2 O 4 . It is one of the oxides of iron , and is ferrimagnetic ; it is attracted to a magnet and can be magnetized to become a permanent magnet itself. With the exception of extremely rare native iron deposits, it is the most magnetic of all the naturally occurring minerals on Earth. Naturally magnetized pieces of magnetite, called lodestone , will attract small pieces of iron, which

284-454: A citizen organization committed to the conservation and preservation of remaining natural area on Staten Island has, since the early 1970s, carried on the mission of its predecessor, SIGNAL. Today the "Protectors" continue the tradition of organizing people concerned about the island's fragile and threatened wilderness via lobbying and naturalist led hikes. A researchable archive of planning, legal, public relations, and other documents related to

355-566: A compass in Tasmania to keep navigation problems to the minimum. Magnetite crystals with a cubic habit are rare but have been found at Balmat, St. Lawrence County, New York , and at Långban, Sweden . This habit may be a result of crystallization in the presence of cations such as zinc. Magnetite can also be found in fossils due to biomineralization and are referred to as magnetofossils . There are also instances of magnetite with origins in space coming from meteorites . Biomagnetism

426-458: A component of protein plaques in the brain. Such plaques have been linked to Alzheimer's disease . Increased iron levels, specifically magnetic iron, have been found in portions of the brain in Alzheimer's patients. Monitoring changes in iron concentrations may make it possible to detect the loss of neurons and the development of neurodegenerative diseases prior to the onset of symptoms due to

497-528: A crystal structure phase transition from a monoclinic structure to a cubic structure known as the Verwey transition . Optical studies show that this metal to insulator transition is sharp and occurs around 120   K. The Verwey transition is dependent on grain size, domain state, pressure, and the iron-oxygen stoichiometry . An isotropic point also occurs near the Verwey transition around 130   K, at which point

568-527: A few path cut through it. When Davis, along with local historian Charles Leng , coauthored a history of Staten Island in 1896, they wrote: The crowning glory of Staten Island’s topography and scenery is the forest that springs from its rich, well-watered soil … Irregularity of contour and excessive wetness have saved such places from village development; and there is hope that some at least may ultimately become parklands, for which purpose they are eminently suited. Just one year later, at an 1897 public hearing on

639-430: A highly porous high-surface-area material, which enhances its effectiveness as a catalyst. Magnetite micro- and nanoparticles are used in a variety of applications, from biomedical to environmental. One use is in water purification: in high gradient magnetic separation, magnetite nanoparticles introduced into contaminated water will bind to the suspended particles (solids, bacteria, or plankton, for example) and settle to

710-431: A human health hazard, airborne magnetite is a result of pollution (specifically combustion). These nanoparticles can travel to the brain via the olfactory nerve, increasing the concentration of magnetite in the brain. In some brain samples, the nanoparticle pollution outnumbers the natural particles by as much as 100:1, and such pollution-borne magnetite particles may be linked to abnormal neural deterioration. In one study,

781-462: A location on Staten Island , New York is a stub . You can help Misplaced Pages by expanding it . Staten Island Greenbelt The Staten Island Greenbelt is a system of contiguous public parkland and natural areas in the central hills of the New York City borough of Staten Island . It is the second largest component of the parks owned by the government of New York City and is maintained by

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852-499: A science important in understanding plate tectonics and as historic data for magnetohydrodynamics and other scientific fields . The relationships between magnetite and other iron oxide minerals such as ilmenite , hematite, and ulvospinel have been much studied; the reactions between these minerals and oxygen influence how and when magnetite preserves a record of the Earth's magnetic field . At low temperatures, magnetite undergoes

923-525: A vast deposit of magnetite-bearing sand dunes in Peru . The dune field covers 250 square kilometers (100 sq mi), with the highest dune at over 2,000 meters (6,560 ft) above the desert floor. The sand contains 10% magnetite. In large enough quantities magnetite can affect compass navigation . In Tasmania there are many areas with highly magnetized rocks that can greatly influence compasses. Extra steps and repeated observations are required when using

994-404: A vehicle for rallying community opposition to the highway construction. From 1966 until the early 1970s, SIGNAL organized thousands of citizens and elected officials (including Planning Commissioner Eleanor Guggenheimer, Parks Commissioner Thomas Hoving , Mayor John V. Lindsay , and U.S. Senator Jacob Javits ) to participate in annual winter walks through the highland forests, tracing the route of

1065-416: Is Fe (Fe ) 2 (O ) 4 . This indicates that magnetite contains both ferrous ( divalent ) and ferric ( trivalent ) iron, suggesting crystallization in an environment containing intermediate levels of oxygen. The main details of its structure were established in 1915. It was one of the first crystal structures to be obtained using X-ray diffraction . The structure is inverse spinel , with O ions forming

1136-517: Is a solid solution between magnetite and ulvospinel that crystallizes in many mafic igneous rocks. Titanomagnetite may undergo oxy-exsolution during cooling, resulting in ingrowths of magnetite and ilmenite. Natural and synthetic magnetite occurs most commonly as octahedral crystals bounded by {111} planes and as rhombic-dodecahedra . Twinning occurs on the {111} plane. Hydrothermal synthesis usually produces single octahedral crystals which can be as large as 10 mm (0.39 in) across. In

1207-703: Is also a chemical basis for cellular sensitivity to electric and magnetic fields ( galvanotaxis ). Pure magnetite particles are biomineralized in magnetosomes , which are produced by several species of magnetotactic bacteria . Magnetosomes consist of long chains of oriented magnetite particle that are used by bacteria for navigation. After the death of these bacteria, the magnetite particles in magnetosomes may be preserved in sediments as magnetofossils. Some types of anaerobic bacteria that are not magnetotactic can also create magnetite in oxygen free sediments by reducing amorphic ferric oxide to magnetite. Several species of birds are known to incorporate magnetite crystals in

1278-426: Is burnt (oxidized) to give magnetite or wüstite of a defined particle size. The magnetite (or wüstite) particles are then partially reduced, removing some of the oxygen in the process. The resulting catalyst particles consist of a core of magnetite, encased in a shell of wüstite, which in turn is surrounded by an outer shell of iron metal. The catalyst maintains most of its bulk volume during the reduction, resulting in

1349-726: Is how ancient peoples first discovered the property of magnetism. Magnetite is black or brownish-black with a metallic luster, has a Mohs hardness of 5–6 and leaves a black streak . Small grains of magnetite are very common in igneous and metamorphic rocks . The chemical IUPAC name is iron(II,III) oxide and the common chemical name is ferrous-ferric oxide . In addition to igneous rocks, magnetite also occurs in sedimentary rocks , including banded iron formations and in lake and marine sediments as both detrital grains and as magnetofossils . Magnetite nanoparticles are also thought to form in soils, where they probably oxidize rapidly to maghemite . The chemical composition of magnetite

1420-734: Is one of the most biologically diverse places in New York City. It is home to several species of amphibians; such as the eastern redback salamander, the green frog, the American bullfrog , and the grey tree frog; reptiles; such as the eastern garter snake , the eastern box turtle , and the northern water snake , as well as New York's state reptile, the common snapping turtle . On occasion northern "black" racer and eastern milksnakes are reported here. Both species are threatened elsewhere on Staten Island due to habitat destruction due to development. The Greenbelt provides year-round habitat native mammals like

1491-595: Is sometimes found in large quantities in beach sand. Such black sands (mineral sands or iron sands ) are found in various places, such as Lung Kwu Tan in Hong Kong; California , United States; and the west coast of the North Island of New Zealand. The magnetite, eroded from rocks, is carried to the beach by rivers and concentrated by wave action and currents. Huge deposits have been found in banded iron formations. These sedimentary rocks have been used to infer changes in

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1562-453: Is still not well understood, and there has been a general lag in applying more modern, interdisciplinary techniques to the study of biomagnetism. Electron microscope scans of human brain-tissue samples are able to differentiate between magnetite produced by the body's own cells and magnetite absorbed from airborne pollution, the natural forms being jagged and crystalline, while magnetite pollution occurs as rounded nanoparticles . Potentially

1633-543: Is the highest elevation south of Maine along the Eastern Seaboard . This and other surface features are the result of glacial activity from the Pleistocene epoch; the metamorphic and igneous rocks below the surface – schist , sandstone, serpentine , magnetite , iron oxide – are the result of tectonic activity from the much earlier Paleozoic era and volcanic activity from subsequent geologic eras. The Greenbelt

1704-452: Is usually related to the presence of biogenic crystals of magnetite, which occur widely in organisms. These organisms range from magnetotactic bacteria (e.g., Magnetospirillum magnetotacticum ) to animals, including humans, where magnetite crystals (and other magnetically sensitive compounds) are found in different organs, depending on the species. Biomagnetites account for the effects of weak magnetic fields on biological systems. There

1775-615: The New York City Planning Commission the strategic and detailed documentation to support this designation. When the work was halted by the city, excavations were used to construct what was known as "Moses Mountain" and now "Paulo's Peak," a 200-foot rise and viewpoint adjacent to the Manor Road - Rockland Avenue interchange. Other remnants of construction can be seen from the Staten Island Expressway between

1846-649: The Raritan Bay and the New York Harbor , offered timber for ship building, iron ore for the production of cannonballs, and a staging ground for British troops during the War for Independence. In the 1800s, several centuries after European settlers had come to, named, deforested, and farmed large portions of Staten Island, travelers of a different sort arrived. Henry David Thoreau - in his furthest journey from his native Massachusetts – came for one year in 1843 in order to tutor

1917-771: The Staten Island Institute of Arts & Sciences ; and New York Times staff writer Alan Oser. Summoning their many and diverse talents, their strategy involved developing and advocating for an alternate route in the press, before public officials, and, when necessary, the courts. One year into the SICPC's legal fight against the original route of the Richmond Parkway, the Staten Island Greenbelt Natural Areas League (SIGNAL), spearheaded by another resident-journalist, John G. Mitchell , formed as

1988-683: The Unitarian Universalist Church of Staten Island, issued the first of many position papers beginning by invoking Olmsted's plea for a linear park; it concluded by presenting an alternate parkway plan that would spare what has come to be known as the Staten Island Greenbelt, a term proposed by landscape architect, Bradford Greene, one of the group's founding members. Greene was familiar with this policy or land use designation from previous work he had been involved with in Maryland . At

2059-536: The gray squirrel , eastern chipmunk , eastern cottontail , and the white-tailed deer . Permanent bird residents include the blue jay , northern cardinal , downy woodpecker, and black-capped chickadee, while northern flickers and other migrants use the Greenbelt as a stopover on seasonal migration routes. Raptors such as Cooper's hawks, redtail hawks, and great horned owls also call the greenbelt home. The waterways are rich in fish life, and such species found here include

2130-457: The largemouth bass , bluegill , green sunfish , brown bullhead , black crappie , yellow perch , chain pickerel , as well as several darter species. The native Lenni- Lenape , who inhabited the island centuries before the arrival of the Dutch, reportedly dubbed Staten Island Aquehonga Monocknong or "the place of bad woods" perhaps because of the spirits they believed dwelled there. Then, as today,

2201-649: The Clove Road and Bradley Avenue exits, which are referred to as the abandoned bridges. They are a little west of the Petrides School Complex. This abandoned interchange was removed as part of a $ 140 million overhaul of the Expressway. In 1982, 25 acres (10 ha) of city-owned land, which heretofore had belonged to the New York City Farm Colony , were added to the Greenbelt; this tract is located on

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2272-521: The QFM buffer. At still lower oxygen levels, magnetite forms a buffer with wüstite known as the MW buffer. The QFM and MW buffers have been used extensively in laboratory experiments on rock chemistry. The QFM buffer, in particular, produces an oxygen fugacity close to that of most igneous rocks. Commonly, igneous rocks contain solid solutions of both titanomagnetite and hemoilmenite or titanohematite. Compositions of

2343-545: The Staten Island Greenbelt, its ecology and history, is housed at the library of the College of Staten Island , a campus of the City University of New York. Containing an extensive system of connected trails and covering 2,800 acres (1,100 ha), its forested hills run the length of Staten Island's midsection while wetlands and kettle ponds fill much of the low-lying areas. Four hundred and ten feet above sea level, Todt Hill

2414-568: The Staten Island Improvement Commission, Olmsted made the following proposal for Staten Island: ...it would be a simple plan to form a park … four miles in length … It would occupy a moderately central position and turn to good use a large extent of land … This ridge extends from the Fresh Kills near Richmondtown to Stapleton . But while its altitude is melted away in gentle slopes to the northward…permitting it that quarter

2485-570: The acreage of which had originally been a part of Pouch Boy Scout Camp, including Orbach Lake, to the north. With a $ 35,000 grant from the State of New York it was bought from the Boy Scouts and established as Camp High Rock for Girls. For thirteen years, the camp served girl scouts from throughout the five boroughs of New York City. However, in 1964, the Girl scout Council of Greater New York secretly decided to sell

2556-460: The bottom of the fluid, allowing the contaminants to be removed and the magnetite particles to be recycled and reused. This method works with radioactive and carcinogenic particles as well, making it an important cleanup tool in the case of heavy metals introduced into water systems. Another application of magnetic nanoparticles is in the creation of ferrofluids . These are used in several ways. Ferrofluids can be used for targeted drug delivery in

2627-414: The boulder-littered moraines were covered with many species of trees: oak, hickory, maple, beech, as well as lesser quantities of birch, sweet gum, ash, black walnut, wild cherry, and tulip. Below the canopy of this sub-climax forest grew dogwood, ironwood, spicebush, blackberry, wild grape, Virginia creeper, and sassafras, along with royal and cinnamon ferns, skunk cabbage, lady slipper, and trout lilies in

2698-410: The brain – magnetite, hemoglobin (blood) and ferritin (protein), and areas of the brain related to motor function generally contain more iron. Magnetite can be found in the hippocampus . The hippocampus is associated with information processing, specifically learning and memory. However, magnetite can have toxic effects due to its charge or magnetic nature and its involvement in oxidative stress or

2769-503: The busy New Springville section of Mid-Island . The Jacques Marchais Center of Tibetan Art and Moore-McMillen House are listed on the National Register of Historic Places . Egbertville is served by the S54 , S57 , S74 and S84 local buses. 40°34′41″N 74°07′31″W  /  40.57806°N 74.12528°W  / 40.57806; -74.12528 This article about

2840-629: The camp to a developer for $ 1 million. Upon learning about this sale, the New York City Parks Department and the State of New York, with the help of the Open Lands Foundation, raised over $ 1.3 million to buy back the land from the developer, thus creating High Rock Park. Then, on November 22, 1965, the Staten Island Citizens Planning Committee (SICPC), which had begun in 1954 as an ad hoc committee of

2911-559: The characteristic nanoparticles were found in the brains of 37 people: 29 of these, aged 3 to 85, had lived and died in Mexico City, a significant air pollution hotspot. Some of the further eight, aged 62 to 92, from Manchester, England, had died with varying severities of neurodegenerative diseases. Such particles could conceivably contribute to diseases like Alzheimer's disease . Though a causal link has not yet been established, laboratory studies suggest that iron oxides such as magnetite are

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2982-507: The city's Department of Parks and Recreation and the Greenbelt Conservancy, a not-for-profit organization that works in partnership with NYC Parks to care for the Greenbelt and raise funds for its maintenance and programs. The Greenbelt includes High Rock Park, LaTourette Park, William T. Davis Wildlife Refuge, and Willowbrook Park among others. The administrative headquarters of the Greenbelt and Greenbelt Conservancy are located at

3053-593: The commissioned report with a recommendation stating that the route to the west of what is today the Greenbelt, was the "least social cost corridor." Under duress from developers who were eager to begin building homes adjacent to the roadway, the Greenbelt's erstwhile supporters, Mayor John Lindsay and Governor Nelson A. Rockefeller , publicly backed a compromise route. In response, the two citizen organizations were willing to stop at nothing to preserve what John Mitchell, in one of his writings, referred to as "a fine patch of wild". With their combined memberships behind them,

3124-726: The construction of a sunken boulevard which would have sped traffic through the middle of the famed Washington Square Park, the Joint Committee to Stop the Lower Manhattan Expressway led by Jane Jacobs , defeated him again. In spite of opposition, road work began in 1965 on what became known as "Section 1". In 1966 Volmer Associates were hired by the city of New York to describe alternate routes to Section 1. They were proposed, studied, and debated by New York state and city officials, creating contention and divisions even within these governmental units. While travel distance between

3195-548: The early 1960s, though then- Triborough Bridge and Tunnel Authority chairman Robert Moses revealed plans for what is now the Korean War Veterans Parkway , a parkway that would connect Brooklyn with New Jersey , traversing the island from the soon to be opened Verrazano-Narrows Bridge on the island's North Shore to the Outerbridge Crossing on the southern shore of Staten Island . This original route of

3266-746: The entrance to High Rock Park (one of the many parks within the system) with a street address of 200 Nevada Avenue in the Egbertville neighborhood; in June 2004 a second facility, known as the Greenbelt Nature Center, was opened approximately 0.75 miles (1.21 km) away, at 700 Rockland Avenue. The Greenbelt Conservancy, which works in partnership with the NYC Parks Department, is a membership organization offering year-round nature-themed events for people of all ages. The Protectors of Pine Oak Woods,

3337-443: The greatest freedom in the location of roads, it descends toward the sea on the south in steep and broken declivities, totally unsuited, not to say impracticable, for roads for rapid travel. Other proposals on behalf of preserving wilderness on Staten Island were put forward in subsequent years. William T. Davis , a naturalist born on the island, believed: The best park is certainly a piece of woodland left as Nature arranged it, with

3408-489: The helm of the SICPC, an all-volunteer organization, were several "off-islanders" – young professionals who had moved to Staten Island's North Shore area in the 1950s largely because of the quality of life promised by the open space that still existed. In addition to Bradford Greene, there were Terrence Benbow and Frank Duffy, both attorneys practicing in Manhattan ; Robert Hagenhofer, a graphic designer; George Pratt, director of

3479-402: The human body. The magnetization of the particles bound with drug molecules allows "magnetic dragging" of the solution to the desired area of the body. This would allow the treatment of only a small area of the body, rather than the body as a whole, and could be highly useful in cancer treatment, among other things. Ferrofluids are also used in magnetic resonance imaging (MRI) technology. For

3550-535: The island's bridges was on paramount concern to the Triborough Bridge and Tunnel Authority, the City Park Department, led by August Hecksher, commissioned the planning firm Wallace, McHarg, Roberts and Todd. Ian McHarg, a Glasgow born landscape architect, who had stated in his much studied book Design with Nature that engineer road builders were "gouging and scarring the landscape without remorse," headed up

3621-596: The island's elected officials or residents. The parkway ends at the Greenbelt's southwestern edge, at Richmond Avenue and Arthur Kill Road , near the Fresh Kills Park . Conservation activists, given immediacy by the Federal Highway Act and hope in the person of President John F. Kennedy's Secretary of the Interior, Stewart Udall , mobilized in opposition to these plans. They first saved High Rock Girl Scout Camp,

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3692-577: The landmark study. Having pointed out that a method for displaying and factoring social values into highway design and planning had not been developed, McHarg set about creating just that. Long before GIS technology was available, McHarg used data rich maps and overlays which allowed planners to visually understand how social values – historic, residential, economic, recreational, scenic, ecological factors – synergistically interacted with and potentially impacted upon human activity, including road building. Using map transparencies he and his colleagues produced

3763-496: The magnetic fields the organism was exposed to, potentially allowing scientists to learn about the migration of the organism or about changes in the Earth's magnetic field over time. Living organisms can produce magnetite. In humans, magnetite can be found in various parts of the brain including the frontal , parietal , occipital , and temporal lobes , brainstem , cerebellum and basal ganglia . Iron can be found in three forms in

3834-454: The magnetite with needle-shaped particles of gamma ferric oxide (γ-Fe 2 O 3 ). Approximately 2–3% of the world's energy budget is allocated to the Haber Process for nitrogen fixation, which relies on magnetite-derived catalysts. The industrial catalyst is obtained from finely ground iron powder, which is usually obtained by reduction of high-purity magnetite. The pulverized iron metal

3905-418: The mineral pairs are used to calculate oxygen fugacity: a range of oxidizing conditions are found in magmas and the oxidation state helps to determine how the magmas might evolve by fractional crystallization . Magnetite also is produced from peridotites and dunites by serpentinization . Lodestones were used as an early form of magnetic compass . Magnetite has been a critical tool in paleomagnetism ,

3976-582: The mineral. In the municipalities of Molinaseca, Albares, and Rabanal del Camino, in the province of León (Spain), there is a magnetite deposit in Ordovician terrain, considered one of the largest in Europe. It was exploited between 1955 and 1982. Deposits are also found in Norway , Romania , and Ukraine . Magnetite-rich sand dunes are found in southern Peru. In 2005, an exploration company, Cardero Resources, discovered

4047-685: The nephews of his friend and fellow transcendentalist , Ralph Waldo Emerson . Some years later, landscape architect Frederick Law Olmsted , famed for his design of urban parks throughout the U.S., settled for a time on a 130 acres (53 ha) experimental farm overlooking the Raritan Bay, which he called Tosomock Farm. After 10 years, he and his new bride left the island only to return later in his life. After Olmsted left Tosomock Farm, businessman Erastus Wiman bought it, renaming it "The Woods of Arden", which stands today at 4515 Hylan Boulevard , near Woods of Arden. In 1871, in his capacity as consultant to

4118-399: The north side of Rockland Avenue, from Brielle Avenue almost to Forest Hill Road. In 1984, the Staten Island Greenbelt was officially recognized by the city, becoming one of the largest natural areas within the five boroughs of New York City and the second largest park in the city, behind Pelham Bay Park . Explanatory notes Citations Bibliography Magnetite Magnetite is

4189-554: The officers of the SICPC and SIGNAL sought injunctive relief in New York State Supreme Court, which meant suing both Lindsay and Rockefeller. The court decision found for the plaintiffs. The citizen planners and conservationists were victorious. The area was earmarked as one of two Special Natural Features Districts in the City of New York, and between 1972 and 1974 the urbanist and architect Peter Verity (now of PDRc) prepared for

4260-670: The oxygen content of the atmosphere of the Earth. Large deposits of magnetite are also found in the Atacama region of Chile ( Chilean Iron Belt ); the Valentines region of Uruguay; Kiruna , Sweden; the Tallawang region of New South Wales; and in the Adirondack Mountains of New York in the United States. Kediet ej Jill , the highest mountain of Mauritania , is made entirely of

4331-403: The presence of mineralizers such as 0.1   M HI or 2   M NH 4 Cl and at 0.207   MPa at 416–800 °C, magnetite grew as crystals whose shapes were a combination of rhombic-dodechahedra forms. The crystals were more rounded than usual. The appearance of higher forms was considered as a result from a decrease in the surface energies caused by the lower surface to volume ratio in

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4402-405: The production of free radicals . Research suggests that beta-amyloid plaques and tau proteins associated with neurodegenerative disease frequently occur after oxidative stress and the build-up of iron. Some researchers also suggest that humans possess a magnetic sense, proposing that this could allow certain people to use magnetoreception for navigation. The role of magnetite in the brain

4473-517: The proposed "Richmond Parkway" would have bisected the swath of land on whose behalf Olmsted had pleaded including what is today Fresh Kills, William T. Davis Wildlife Refuge , Reed's Basket Willow Swamp, Willowbrook and High Rock Park. The 4.8-mile (7.7 km) parkway route going through the area has been de-mapped despite occasional proposals for its revival due to steadily increasing highway congestion on Staten Island. None of these proposals, however, have received any significant support from either

4544-472: The proposed (and already mapped) highway route. These two citizen organizations and their combined strategies of lobbying, public relations, and grassroots organizing challenged Robert Moses, who had been thwarted by community efforts only twice before: In 1956, mothers who frequented Manhattan's Central Park with their young children successfully had stopped a proposed parking lot expansion by challenging Moses in court. Two years later, when Robert Moses proposed

4615-534: The relationship between magnetite and ferritin . In tissue, magnetite and ferritin can produce small magnetic fields which will interact with magnetic resonance imaging (MRI) creating contrast. Huntington patients have not shown increased magnetite levels; however, high levels have been found in study mice. Due to its high iron content, magnetite has long been a major iron ore . It is reduced in blast furnaces to pig iron or sponge iron for conversion to steel . Audio recording using magnetic acetate tape

4686-427: The rounded crystals. Magnetite has been important in understanding the conditions under which rocks form. Magnetite reacts with oxygen to produce hematite , and the mineral pair forms a buffer that can control how oxidizing its environment is (the oxygen fugacity ). This buffer is known as the hematite-magnetite or HM buffer. At lower oxygen levels, magnetite can form a buffer with quartz and fayalite known as

4757-420: The sign of the magnetocrystalline anisotropy constant changes from positive to negative. The Curie temperature of magnetite is 580 °C (853 K; 1,076 °F). If magnetite is in a large enough quantity it can be found in aeromagnetic surveys using a magnetometer which measures magnetic intensities. Solid magnetite particles melt at about 1,583–1,597 °C (2,881–2,907 °F). Magnetite

4828-503: The topic of land preservation in Albany , the state's capital, Staten Island resident Erastus Wiman stated: [The land is] a wilderness of such beauty pervaded this region that no expenditure could improve upon. During the first half of the 20th century, several proposals for Staten Island parks and parkways were drafted first by the Borough of Staten Island and then by the City of New York. During

4899-453: The upper beak for magnetoreception , which (in conjunction with cryptochromes in the retina ) gives them the ability to sense the direction, polarity , and magnitude of the ambient magnetic field . Chitons , a type of mollusk, have a tongue-like structure known as a radula , covered with magnetite-coated teeth, or denticles . The hardness of the magnetite helps in breaking down food. Biological magnetite may store information about

4970-476: The wetter areas. Within the oak-mulch enriched soil that has been laid down over millennia, arrowheads have been found. These finds attest to both the Leni-Lenape's subsistence on and unsuccessful defense of their home, which contained the natural resources that made it so attractive to first Dutch and then British colonizers in the 17th and 18th centuries. Its forested hills, strategically located between and above

5041-476: Was developed in the 1930s. The German magnetophon first utilized magnetite powder that BASF coated onto cellulose acetate before soon switching to gamma ferric oxide for its superior morphology. Following World War II , 3M Company continued work on the German design. In 1946, the 3M researchers found they could also improve their own magnetite-based paper tape, which utilized powders of cubic crystals, by replacing

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