rajpurkar/squad huggingface dataset:
Title: Great_Plains

The rural Plains have lost a third of their population since 1920. Several hundred thousand square miles (several hundred thousand square kilometers) of the Great Plains have fewer than 6 inhabitants per square mile (2.3 inhabitants per square kilometer)—the density standard Frederick Jackson Turner used to declare the American frontier "closed" in 1893. Many have fewer than 2 inhabitants per square mile (0.77 inhabitants per square kilometer). There are more than 6,000 ghost towns in the state of Kansas alone, according to Kansas historian Daniel Fitzgerald. This problem is often exacerbated by the consolidation of farms and the difficulty of attracting modern industry to the region. In addition, the smaller school-age population has forced the consolidation of school districts and the closure of high schools in some communities. The continuing population loss has led some to suggest that the current use of the drier parts of the Great Plains is not sustainable, and there has been a proposal - the "Buffalo Commons" - to return approximately 139,000 square miles (360,000 km2) of these drier parts to native prairie land.

Question: how much of the population have the rural plains lost since 1920? 
Answer: a third

Question: who declated the American frontier "closed" in 1893?
Answer: Frederick Jackson Turner

Question: how many ghost towns are in the state of Kansas?
Answer: more than 6,000

Question: how much prarie land does the "Buffalo Commons" want to return?
Answer: 139,000 square miles
Title: Great_Plains

Although the eastern image of farm life in the prairies emphasized the isolation of the lonely farmer and wife, plains residents created busy social lives for themselves. They often sponsored activities that combined work, food and entertainment such as barn raisings, corn huskings, quilting bees, Grange meetings, church activities and school functions. Women organized shared meals and potluck events, as well as extended visits between families. The Grange was a nationwide farmers' organization, they reserved high offices for women, and gave them a voice in public affairs.

Question: who usually organized shared meals and potluck events?
Answer: Women
Title: Great_Plains

From the 1950s on, many areas of the Great Plains have become productive crop-growing areas because of extensive irrigation on large landholdings. The United States is a major exporter of agricultural products. The southern portion of the Great Plains lies over the Ogallala Aquifer, a huge underground layer of water-bearing strata dating from the last ice age. Center pivot irrigation is used extensively in drier sections of the Great Plains, resulting in aquifer depletion at a rate that is greater than the ground's ability to recharge.

Question: around when did the great plains become productive for crop growing
Answer: 1950s

Question: what is the large underground layer of water in the great plains called?
Answer: Ogallala Aquifer

Question: what type of irrigation is used in the great plains?
Answer: Center pivot irrigation
Title: Great_Plains

The Great Plains is the broad expanse of flat land (a plain), much of it covered in prairie, steppe and grassland, that lies west of the Mississippi River tallgrass prairie states and east of the Rocky Mountains in the United States and Canada. This area covers parts, but not all, of the states of Colorado, Kansas, Montana, Nebraska, New Mexico, North Dakota, Oklahoma, South Dakota, Texas, and Wyoming, and the Canadian provinces of Alberta, Manitoba and Saskatchewan. The region is known for supporting extensive cattle ranching and dry farming.

Question: what is the great plains?
Answer: broad expanse of flat land

Question: where does the great plains lie?
Answer: west of the Mississippi River

Question: what is the region known for?
Answer: extensive cattle ranching
Title: Great_Plains

The North American Environmental Atlas, produced by the Commission for Environmental Cooperation, a NAFTA agency composed of the geographical agencies of the Mexican, American, and Canadian governments uses the "Great Plains" as an ecoregion synonymous with predominant prairies and grasslands rather than as physiographic region defined by topography. The Great Plains ecoregion includes five sub-regions: Temperate Prairies, West-Central Semi-Arid Prairies, South-Central Semi-Arid Prairies, Texas Louisiana Coastal Plains, and Tamaulipus-Texas Semi-Arid Plain, which overlap or expand upon other Great Plains designations.

Question: who is the North American Environmental Atlas made by?
Answer: Commission for Environmental Cooperation

Question: what countries is the Commission for Environmental Cooperation made up of?
Answer: Mexican, American, and Canadian governments
Title: Great_Plains

The railroads opened up the Great Plains for settlement, for now it was possible to ship wheat and other crops at low cost to the urban markets in the East, and Europe. Homestead land was free for American settlers. Railroads sold their land at cheap rates to immigrants in expectation they would generate traffic as soon as farms were established. Immigrants poured in, especially from Germany and Scandinavia. On the plains, very few single men attempted to operate a farm or ranch by themselves; they clearly understood the need for a hard-working wife, and numerous children, to handle the many chores, including child-rearing, feeding and clothing the family, managing the housework, feeding the hired hands, and, especially after the 1930s, handling paperwork and financial details. During the early years of settlement, farm women played an integral role in assuring family survival by working outdoors. After approximately one generation, women increasingly left the fields, thus redefining their roles within the family. New technology including sewing and washing machines encouraged women to turn to domestic roles. The scientific housekeeping movement, promoted across the land by the media and government extension agents, as well as county fairs which featured achievements in home cookery and canning, advice columns for women regarding farm bookkeeping, and home economics courses in the schools.

Question: what mainly opened the great plains for settlement?
Answer: railroads

Question: what did the railroads make it easy to do?
Answer: ship wheat and other crops

Question: who did the railroads sell cheap lands to?
Answer: immigrants

Question: who two new technologies were introducted in the 1930s?
Answer: sewing and washing machines
Title: Great_Plains

During the Cenozoic era, specifically about 25 million years ago during the Miocene and Pliocene epochs, the continental climate became favorable to the evolution of grasslands. Existing forest biomes declined and grasslands became much more widespread. The grasslands provided a new niche for mammals, including many ungulates and glires, that switched from browsing diets to grazing diets. Traditionally, the spread of grasslands and the development of grazers have been strongly linked. However, an examination of mammalian teeth suggests that it is the open, gritty habitat and not the grass itself which is linked to diet changes in mammals, giving rise to the "grit, not grass" hypothesis.

Question: about how long ago did the climate become favorable?
Answer: about 25 million years ago

Question: what animals did the grasslands provide a new home for?
Answer: mammals

Question: what diet did the mammals switch to from browsing diets?
Answer: grazing diets

Question: the spread of grasslands and what have been strongly linked?
Answer: development of grazers
Title: Great_Plains

To allow for agricultural development of the Great Plains and house a growing population, the US passed the Homestead Acts of 1862: it allowed a settler to claim up to 160 acres (65 ha) of land, provided that he lived on it for a period of five years and cultivated it. The provisions were expanded under the Kinkaid Act of 1904 to include a homestead of an entire section. Hundreds of thousands of people claimed such homesteads, sometimes building sod houses out of the very turf of their land. Many of them were not skilled dryland farmers and failures were frequent. Much of the Plains were settled during relatively wet years. Government experts did not understand how farmers should cultivate the prairies and gave advice counter to what would have worked[citation needed]. Germans from Russia who had previously farmed, under similar circumstances, in what is now Ukraine were marginally more successful than other homesteaders. The Dominion Lands Act of 1871 served a similar function for establishing homesteads on the prairies in Canada.

Question: when did the US pass the Homestead ACt?
Answer: 1862

Question: how much land did the Homestead Act allow a person to claim?
Answer: up to 160 acres

Question: how long did the person have to live on the land?
Answer: five years

Question: when was the Kinkaid Act brought about? 
Answer: 1904

Question: the dominion act was passed in what year
Answer: 1871
Title: Infrared

Infrared radiation is used in industrial, scientific, and medical applications. Night-vision devices using active near-infrared illumination allow people or animals to be observed without the observer being detected. Infrared astronomy uses sensor-equipped telescopes to penetrate dusty regions of space, such as molecular clouds; detect objects such as planets, and to view highly red-shifted objects from the early days of the universe. Infrared thermal-imaging cameras are used to detect heat loss in insulated systems, to observe changing blood flow in the skin, and to detect overheating of electrical apparatus.

Question: What technology is used by night-vision devices?
Answer: active near-infrared illumination

Question: What discipline uses infrared telescopes to see through molecular clouds?
Answer: Infrared astronomy

Question: What color shift indicates that space objects date from the early days of the universe?
Answer: red

Question: What devices are used to observe insulated system heat loss?
Answer: Infrared thermal-imaging cameras

Question: Along with industrial and medical, in what applications is infrared radiation used?
Answer: scientific
Title: Infrared

The onset of infrared is defined (according to different standards) at various values typically between 700 nm and 800 nm, but the boundary between visible and infrared light is not precisely defined. The human eye is markedly less sensitive to light above 700 nm wavelength, so longer wavelengths make insignificant contributions to scenes illuminated by common light sources. However, particularly intense near-IR light (e.g., from IR lasers, IR LED sources, or from bright daylight with the visible light removed by colored gels) can be detected up to approximately 780 nm, and will be perceived as red light. Sources providing wavelengths as long as 1050 nm can be seen as a dull red glow in intense sources, causing some difficulty in near-IR illumination of scenes in the dark (usually this practical problem is solved by indirect illumination). Leaves are particularly bright in the near IR, and if all visible light leaks from around an IR-filter are blocked, and the eye is given a moment to adjust to the extremely dim image coming through a visually opaque IR-passing photographic filter, it is possible to see the Wood effect that consists of IR-glowing foliage.

Question: At what wavelength does the human eye become significantly less sensitive to light?
Answer: 700 nm

Question: What sort of light is generated by IR lasers?
Answer: near-IR

Question: Up to what wavelength does the human eye perceive IR LED sources as red?
Answer: 780 nm

Question: Up to what wavelength does the human eye perceive certain intense lights as being dull red in color?
Answer: 1050 nm

Question: What objects are notably bright in near IR?
Answer: Leaves
Title: Infrared

The concept of emissivity is important in understanding the infrared emissions of objects. This is a property of a surface that describes how its thermal emissions deviate from the ideal of a black body. To further explain, two objects at the same physical temperature will not show the same infrared image if they have differing emissivity. For example, for any pre-set emissivity value, objects with higher emissivity will appear hotter, and those with a lower emissivity will appear cooler. For that reason, incorrect selection of emissivity will give inaccurate results when using infrared cameras and pyrometers.

Question: What is the term for the property that describes how a surface's thermal emissions deviate from the ideal of a black body?
Answer: emissivity

Question: How will the infrared image of an object with a higher emissivity appear in relation to one with lower emissivity?
Answer: hotter

Question: Along with pyrometers, what devices can receive inaccurate results if emissivity is not set correctly?
Answer: infrared cameras
Title: Infrared

Infrared vibrational spectroscopy (see also near-infrared spectroscopy) is a technique that can be used to identify molecules by analysis of their constituent bonds. Each chemical bond in a molecule vibrates at a frequency characteristic of that bond. A group of atoms in a molecule (e.g., CH2) may have multiple modes of oscillation caused by the stretching and bending motions of the group as a whole. If an oscillation leads to a change in dipole in the molecule then it will absorb a photon that has the same frequency. The vibrational frequencies of most molecules correspond to the frequencies of infrared light. Typically, the technique is used to study organic compounds using light radiation from 4000–400 cm−1, the mid-infrared. A spectrum of all the frequencies of absorption in a sample is recorded. This can be used to gain information about the sample composition in terms of chemical groups present and also its purity (for example, a wet sample will show a broad O-H absorption around 3200 cm−1).

Question: What is the technique that analyzes the constituent bonds of molecules to identify them?
Answer: Infrared vibrational spectroscopy

Question: What happens to a molecule if an oscillation results in a dipole being changed?
Answer: it will absorb a photon that has the same frequency

Question: What do the vibrational frequencies of molecules usually correspond to?
Answer: the frequencies of infrared light

Question: What is the term for light radiation in the 4000–400 cm−1 spectrum?
Answer: the mid-infrared
Title: Infrared

In infrared photography, infrared filters are used to capture the near-infrared spectrum. Digital cameras often use infrared blockers. Cheaper digital cameras and camera phones have less effective filters and can "see" intense near-infrared, appearing as a bright purple-white color. This is especially pronounced when taking pictures of subjects near IR-bright areas (such as near a lamp), where the resulting infrared interference can wash out the image. There is also a technique called 'T-ray' imaging, which is imaging using far-infrared or terahertz radiation. Lack of bright sources can make terahertz photography more challenging than most other infrared imaging techniques. Recently T-ray imaging has been of considerable interest due to a number of new developments such as terahertz time-domain spectroscopy.

Question: What is used in infrared photography to capture the near-infrared spectrum?
Answer: infrared filters

Question: What devices are often equipped with infrared blockers?
Answer: Digital cameras

Question: What is the technique that involves imaging with terahertz radiation?
Answer: 'T-ray' imaging

Question: What is another name for terahertz radiation?
Answer: far-infrared

Question: What is a notable recent development in T-ray imaging?
Answer: terahertz time-domain spectroscopy
Title: Infrared

Infrared reflectography (fr; it; es), as called by art conservators, can be applied to paintings to reveal underlying layers in a completely non-destructive manner, in particular the underdrawing or outline drawn by the artist as a guide. This often reveals the artist's use of carbon black, which shows up well in reflectograms, as long as it has not also been used in the ground underlying the whole painting. Art conservators are looking to see whether the visible layers of paint differ from the underdrawing or layers in between – such alterations are called pentimenti when made by the original artist. This is very useful information in deciding whether a painting is the prime version by the original artist or a copy, and whether it has been altered by over-enthusiastic restoration work. In general, the more pentimenti the more likely a painting is to be the prime version. It also gives useful insights into working practices.

Question: What technique is used in art to examine underlying layers of a painting without damaging it?
Answer: Infrared reflectography

Question: What shows up particularly well in reflectograms?
Answer: carbon black

Question: What is the term for differences in the painting and underdrawing made by the original artist?
Answer: pentimenti
Title: Infrared

The discovery of infrared radiation is ascribed to William Herschel, the astronomer, in the early 19th century. Herschel published his results in 1800 before the Royal Society of London. Herschel used a prism to refract light from the sun and detected the infrared, beyond the red part of the spectrum, through an increase in the temperature recorded on a thermometer. He was surprised at the result and called them "Calorific Rays". The term 'Infrared' did not appear until late in the 19th century.

Question: Who discovered infrared radiation?
Answer: William Herschel

Question: To whom did Herschel present his work on infrared radiation?
Answer: the Royal Society of London

Question: In what year did Herschel publish his work on infrared radiation?
Answer: 1800

Question: What device did Herschel use to discover the infrared?
Answer: a prism

Question: What did Herschel call the infrared spectrum?
Answer: Calorific Rays
Title: Infrared

Infrared radiation is popularly known as "heat radiation"[citation needed], but light and electromagnetic waves of any frequency will heat surfaces that absorb them. Infrared light from the Sun accounts for 49% of the heating of Earth, with the rest being caused by visible light that is absorbed then re-radiated at longer wavelengths. Visible light or ultraviolet-emitting lasers can char paper and incandescently hot objects emit visible radiation. Objects at room temperature will emit radiation concentrated mostly in the 8 to 25 µm band, but this is not distinct from the emission of visible light by incandescent objects and ultraviolet by even hotter objects (see black body and Wien's displacement law).

Question: What is a commonly used term for infrared radiation?
Answer: heat radiation

Question: What percentage of the Earth's heat is derived from the Sun's infrared light?
Answer: 49%

Question: What is the common range of emitted radiation of room temperature objects, in micrometers? 
Answer: 8 to 25

Question: Other than infrared light, what type of light is responsible for heating the Earth?
Answer: visible
Title: Infrared

Infrared tracking, also known as infrared homing, refers to a passive missile guidance system, which uses the emission from a target of electromagnetic radiation in the infrared part of the spectrum to track it. Missiles that use infrared seeking are often referred to as "heat-seekers", since infrared (IR) is just below the visible spectrum of light in frequency and is radiated strongly by hot bodies. Many objects such as people, vehicle engines, and aircraft generate and retain heat, and as such, are especially visible in the infrared wavelengths of light compared to objects in the background.

Question: What is another term for infrared homing?
Answer: Infrared tracking

Question: What devices make use of infrared homing?
Answer: Missiles

Question: What is a common name for missiles that make use of infrared seeking?
Answer: heat-seekers

Question: Along with aircraft and people, what objects notably create and retain heat?
Answer: vehicle engines

Question: What does IR stand for?
Answer: infrared
Title: Infrared

High, cold ice clouds such as Cirrus or Cumulonimbus show up bright white, lower warmer clouds such as Stratus or Stratocumulus show up as grey with intermediate clouds shaded accordingly. Hot land surfaces will show up as dark-grey or black. One disadvantage of infrared imagery is that low cloud such as stratus or fog can be a similar temperature to the surrounding land or sea surface and does not show up. However, using the difference in brightness of the IR4 channel (10.3–11.5 µm) and the near-infrared channel (1.58–1.64 µm), low cloud can be distinguished, producing a fog satellite picture. The main advantage of infrared is that images can be produced at night, allowing a continuous sequence of weather to be studied.

Question: Along with Cirrus, what types of clouds are cold and high?
Answer: Cumulonimbus

Question: What color do Cirrus clouds appear in infrared?
Answer: white

Question: Along with Stratus, what clouds are lower and warmer?
Answer: Stratocumulus

Question: What color are Strarus clouds in infrared?
Answer: grey

Question: What is the range of the near-infrared channel in micrometers?
Answer: 1.58–1.64
Title: Infrared

The sensitivity of Earth-based infrared telescopes is significantly limited by water vapor in the atmosphere, which absorbs a portion of the infrared radiation arriving from space outside of selected atmospheric windows. This limitation can be partially alleviated by placing the telescope observatory at a high altitude, or by carrying the telescope aloft with a balloon or an aircraft. Space telescopes do not suffer from this handicap, and so outer space is considered the ideal location for infrared astronomy.

Question: What limits the sensitivity of infrared telescopes on Earth?
Answer: water vapor in the atmosphere

Question: To somewhat avoid the water vapor in the atmosphere, where can an observatory be sited?
Answer: at a high altitude

Question: Along with aircraft, what object can be used to carry a telescope aloft?
Answer: balloon

Question: What sorts of telescopes completely avoid water vapor in Earth's atmosphere?
Answer: Space telescopes
Title: Infrared

Near-infrared is the region closest in wavelength to the radiation detectable by the human eye, mid- and far-infrared are progressively further from the visible spectrum. Other definitions follow different physical mechanisms (emission peaks, vs. bands, water absorption) and the newest follow technical reasons (the common silicon detectors are sensitive to about 1,050 nm, while InGaAs's sensitivity starts around 950 nm and ends between 1,700 and 2,600 nm, depending on the specific configuration). Unfortunately, international standards for these specifications are not currently available.

Question: What is the nearest wavelength to the radiation that a human eye can see?
Answer: Near-infrared

Question: Along with the emission peaks and vs. bands mechanisms, what other physical mechanism is used to define near-infrared?
Answer: water absorption

Question: In micrometers, when do common silicon detectors cease to be sensitive?
Answer: 1,050

Question: What is the lowest level of sensitivity, in micrometers, for InGaAs?
Answer: 950