People Grew Shorter Growing Crops
Analysis by Tim Wall
The dawn of agriculture around the world was accompanied by a surprising trend. From China to South America and everywhere in between, people in farming cultures became shorter and less healthy than their hunter-gathering ancestors.
Amanda Mummert, an anthropology graduate student at Emory University, led a first of its kind review of health and height statistics from the days when agriculture sprouted around the world.
“Many people have this image of the rise of agriculture and the dawn of modern civilization, and they just assume that a more stable food source makes you healthier,”
"Early agriculturists had a harder time adapting to stress," says anthropologist Amanda Mummert. (Credit: iStockphoto.com.)
By Carol Clark
When populations around the globe started turning to agriculture around 10,000 years ago, regardless of their locations and type of crops, a similar trend occurred: The height and health of the people declined.
“This broad and consistent pattern holds up when you look at standardized studies of whole skeletons in populations,” says Amanda Mummert, an Emory graduate student in anthropology.
Mummert (in photo at right) led the first comprehensive, global review of the literature regarding stature and health during the agriculture transition, to be published by the journal Economics and Human Biology.
“Many people have this image of the rise of agriculture and the dawn of modern civilization, and they just assume that a more stable food source makes you healthier,” Mummert says. “But early agriculturalists experienced nutritional deficiencies and had a harder time adapting to stress, probably because they became dependent on particular food crops, rather than having a more significantly diverse diet.”
She adds that growth in population density spurred by agriculture settlements led to an increase in infectious diseases, likely exacerbated by problems of sanitation and the proximity to domesticated animals and other novel disease vectors.
Eventually, the trend toward shorter stature reversed, and average heights for most populations began increasing. The trend is especially notable in the developed world during the past 75 years, following the industrialization of food systems.
“Culturally, we’re agricultural chauvinists. We tend to think that producing food is always beneficial, but the picture is much more complex than that,” says Emory anthropologist George Armelagos, co-author of the review. “Humans paid a heavy biological cost for agriculture, especially when it came to the variety of nutrients. Even now, about 60 percent of our calories come from corn, rice and wheat.”
"Humans paid a heavy biological cost for agriculture," says anthropologist George Armelagos. (Credit: iStockphoto.com.)
In 1984, Armelagos and M. N. Cohen wrote a groundbreaking book, “Paleopathology at the Origins of Agriculture,” which drew from more than 20 studies to describe an increase in declining health and nutritional diseases as societies shifted from foraging to agriculture.
The book was controversial at the time, but the link between the agricultural transition and declining health soon became widely accepted in what was then the emerging field of bioarcheology.
The current review was undertaken to compare data from more recent studies involving different world regions, crops and cultures. The studies included populations from areas of China, Southeast Asia, North and South America and Europe. All of the papers used standardized methods for assessing health at the individual level and examined how stressors were exhibited within the entire skeleton, rather than a concentration on a particular skeletal element or condition.
“Unless you’re considering a complete skeleton, you’re not getting a full picture of health,” Mummert says. “You could have an individual with perfect teeth, for example, but serious markers of infection elsewhere. You could see pitting on the skull, likely related to anemia or nutritional stress, but no marks at all on the long bones.”
Adult height, dental cavities and abscesses, bone density and healed fractures are some of the markers used to try to paint a more complete picture of an individual’s health.
“Bones are constantly remodeling themselves,” Mummert says. “Skeletons don’t necessarily tell you what people died of, but they can almost always give you a glimpse into their ability to adapt and survive.”
While the review further supports the link between early agricultural practices and declining stature and health, it’s important to keep re-evaluating the data as more studies are completed, Mummert says.
"Even now, about 60 percent of our calories come from corn, rice and wheat," Armelagos says. (Credit: iStockphoto.com.)
One confounding factor is that agriculture was not adopted in an identical fashion and time span across the globe. In some ancient societies, such as those of the North American coasts, crops may have merely supplemented a seafood diet. “In these cases, a more sedentary lifestyle, and not necessarily agriculture, could have perpetuated decreased stature,” Mummert says.
The way the human body adapted to changes we made in the environment 10,000 years ago could help us understand how our bodies are adapting now, she says.
Some economists and other scientists are using the rapid physiological increases in human stature during the 20th century as a key indicator of better health.
“I think it’s important to consider what exactly ‘good health’ means,” Mummert says. “The modernization and commercialization of food may be helping us by providing more calories, but those calories may not be good for us. You need calories to grow bones long, but you need rich nutrients to grow bones strong.”
Croatia does not have a reputation as a hotbed of ancient agriculture. But new excavations, described January 7 in San Antonio at the annual meeting of the Archaeological Institute of America, unveil a Mediterranean Sea -- hugging strip of southern Croatia as a hub for early farmers who spread their sedentary lifestyle from the Middle East into Europe.
Farming villages sprouted swiftly in this coastal region, called Dalmatia, nearly 8,000 years ago, apparently with the arrival of Middle Easterners already adept at growing crops and herding animals, says archaeologist Andrew Moore of Rochester Institute of Technology in New York.
Moore codirects an international research team, with archaeologist Marko Mendušic of Croatia’s Ministry of Culture in Šibenik, that has uncovered evidence of intensive farming at Pokrovnik and Danilo Bitinj, two Neolithic settlements in Dalmatia. Plant cultivation and animal raising started almost 8,000 years ago at Pokrovnik and lasted for close to a millennium, according to radiocarbon dating of charred seeds and bones from a series of occupation layers. Comparable practices at Danilo Bitinj lasted from about 7,300 to 6,800 years ago.
"Farming came to Dalmatia abruptly, spread rapidly and took hold immediately," Moore says.
Other evidence supports a fast spread of sophisticated farming methods from the Middle East into Europe (SN: 2/5/05, p. 88), remarks Harvard University archaeologist Ofer Bar-Yosef. Farming villages in western Greece date to about 9,000 years ago, he notes. Middle Eastern farmers exploited a wide array of domesticated plants and animals by 10,500 years ago, setting the stage for a westward migration, Bar-Yosef says.
Other researchers began excavating Pokrovnik and Danilo Bitinj more than 40 years ago. Only Moore and his colleagues dug deep enough to uncover signs of intensive farming.
Their discoveries support the idea that agricultural newcomers to southern Europe built villages without encountering local nomadic groups, Moore asserts. Earlier excavations at Neolithic sites in Germany and France raise the possibility that hunter-gatherers clashed with incoming villagers in northern Europe, he notes.
Surprisingly, Pokrovnik and Danilo Bitinj residents grew the same plants and raised the same animals, in the same proportions, as today’s Dalmatian farmers do, Moore says. Excavated seeds and plant parts show that ancient villagers grew nine different domestic plants -- including emmer, oats and lentils -- and gathered blackberries and other wild fruits.
Animal bones found at the two villages indicate that residents primarily herded sheep and goats, along with some cattle and a small number of pigs.
Diverse food sources provided a hedge against regional fluctuations in rainfall and growing seasons, according to Moore. "This is an astonishing demonstration of agricultural continuity from the Neolithic to present times," he says.
Aside from farming, Neolithic villagers in Dalmatia were "oriented toward the sea, and enjoyed extensive long-distance contacts," Moore adds. Chemical analyses of obsidian chunks found at Pokrovnik and Danilo Bitinj, directed by archaeologist Robert Tykot of the University of South Florida in Tampa, trace most of them to Lipari, an island off Sicily’s north coast.
Shapes and styles of pottery from the ancient Dalmatian villages changed dramatically several times during the Neolithic. Moore’s team can’t explain why these shifts occurred while the farming economy remained the same.
Other than three children found in separate graves, the researchers have unearthed no human skeletons at Pokrovnik and Danilo Bitinj.
“But early agriculturalists experienced nutritional deficiencies and had a harder time adapting to stress, probably because they became dependent on particular food crops, rather than having a more significantly diverse diet,” Mummert said.
“Culturally, we’re agricultural chauvinists. We tend to think that producing food is always beneficial, but the picture is much more complex than that,” says Emory anthropologist George Armelagos, professor of anthropology and co-author of the study.
Starting around 10,000 years ago, and continuing to relatively recently, no matter where and what crop, the pattern was the same. Agriculture led to shorter, less healthy people.
The spread of disease in concentrated settlements, as well as transmission of diseases from animals may have also played a part.
Gradually the trend reversed, especially after the dawn of mechanized agriculture in the developed world about 75 years ago, noted the authors.
“This broad and consistent pattern holds up when you look at standardized studies of whole skeletons in populations,” Mummert said.
Mummert reviewed literature studying factors like adult height, dental cavities and abscesses, bone density, healed fractures, and other indicators of health from populations around the world as they started farming. The populations came from far-flung areas of the globe, including China, Southeast Asia, North and South America, and Europe.
In 1968, William Guad, the director of the United States Agency for International Development (USAID) at the time, coined the term “the green revolution” when describing a series of agricultural advancements that prompted increased crop yields across the planet.
The revolution was much greener than Guad could have imagined, according to a new study in the journal Proceedings of the National Academy of Sciences.
Jennifer Burney, a scientist at Stanford University, lead a research team that looked at greenhouse gas emissions from modern agriculture, which currently contributes to around 12 percent of total global carbon dioxide emissions.
The researchers then calculated how much CO2 would have been released if the green revolution had not happened, but farmers were using more primitive methods to produce today’s amount of crops.
Before more efficient farming methods were invented, farmers relied on a simple technique for increasing production: acquiring more land. Clearing forests and other vegetation by burning them.
This method was easy and cheap, but it released huge amounts of greenhouse gases like methane, nitrous oxide and carbon dioxide into the atmosphere. By developing high-yield agricultural techniques, farmers avoided burning up loads of natural landscapes and in recent decades saved up to 590 billion metric tons of carbon dioxide from being released into the atmosphere.
“Our results dispel the notion that modern intensive agricultural is inherently worse for the environment than a more ‘old-fashioned’ way of doing things,” Burney said.
“Bones are constantly remodeling themselves,” Mummert said. “Skeletons don’t necessarily tell you what people died of, but they can almost always give you a glimpse into their ability to adapt and survive.”
“Humans paid a heavy biological cost for agriculture, especially when it came to the variety of nutrients. Even now, about 60 percent of our calories come from corn, rice and wheat,” said Armelagos.
Carbon dioxide deserves most of the blame for trapping heat in the Earth's atmosphere, but it has accomplices. The third most common greenhouse gas in the atmosphere is nitrous oxide, which is about 300 times more effective at trapping heat than carbon dioxide.
The majority of the world's nitrous oxide emissions come from agriculture in the U.S. But researchers at the University of Missouri – Columbia have found a way to limit the greenhouse gas without making farmer's lives more difficult. In fact the technique can also help farmers save money and improve their yields.
SEE ALSO: Better Than Farmville: A Simulated Century of Farming
“The main goal for our team has been to identify agricultural practices that maintain or increase production while reducing the environmental impact,” said Peter Motavalli of the University of Missouri.
In the past, most farmers tilled whole fields, but that caused tremendous problems with erosion. The Dust Bowl was largely caused by over-tilling the easily eroded soils of the Great Plains. To avoid the fate of the Joad family in John Steinbeck's The Grapes of Wrath, American farmers changed their practices to better conserve the soil.
Now, many farmers do not till their fields, but this increases fertilizer run-off. Also, when soil bacteria finds a tasty combination of nitrogen fertilizer and oxygen on the surface, they eat it up and release nitrous oxide.
The university researchers experimented with the technique of tilling strips of the field about a foot wide and eight to nine inches deep. This allows farmers to use less gas in their tractors while still leaving crop residues, like corn stalks, on the field's surface to prevent erosion.
SEE ALSO: Potential Biofuel Cropland Plentiful
When farmers till strips and apply fertilizer into the soil of the furrows, the nitrogen fertilizers don't run off and pollute waterways. It also improves yield since more fertilizer gets to the plants.
Here's where the climate benefits come in. By placing the nitrogen fertilizer into the furrows, less of the chemical is converted into nitrous oxide by air-breathing soil microbes.
SEE ALSO: Biofuel Grasslands For the Birds
The researchers conducted their study in northeast Missouri from 2008 to 2010. One field was “strip tilled” with nitrogen fertilizer placed in a band in the soil, while another field was left untilled with a surface application of nitrogen fertilizer.
The idea that agriculture led to a decline in health was pioneered by Armelos and M. N. Cohen back in 1984 in the book Paleoanthropology at the Origins of Agriculture. Though it was controversial at the time, the idea is now widely accepted.
This new study shows how widespread the link between agriculture and declining health was, and gathers into one place the numbers to back-up the assertion.
Discovery News
The dawn of agriculture around the world was accompanied by a surprising trend. From China to South America and everywhere in between, people in farming cultures became shorter and less healthy than their hunter-gathering ancestors.
Amanda Mummert, an anthropology graduate student at Emory University, led a first of its kind review of health and height statistics from the days when agriculture sprouted around the world.
“Many people have this image of the rise of agriculture and the dawn of modern civilization, and they just assume that a more stable food source makes you healthier,”
"Early agriculturists had a harder time adapting to stress," says anthropologist Amanda Mummert. (Credit: iStockphoto.com.)
By Carol Clark
When populations around the globe started turning to agriculture around 10,000 years ago, regardless of their locations and type of crops, a similar trend occurred: The height and health of the people declined.
“This broad and consistent pattern holds up when you look at standardized studies of whole skeletons in populations,” says Amanda Mummert, an Emory graduate student in anthropology.
Mummert (in photo at right) led the first comprehensive, global review of the literature regarding stature and health during the agriculture transition, to be published by the journal Economics and Human Biology.
“Many people have this image of the rise of agriculture and the dawn of modern civilization, and they just assume that a more stable food source makes you healthier,” Mummert says. “But early agriculturalists experienced nutritional deficiencies and had a harder time adapting to stress, probably because they became dependent on particular food crops, rather than having a more significantly diverse diet.”
She adds that growth in population density spurred by agriculture settlements led to an increase in infectious diseases, likely exacerbated by problems of sanitation and the proximity to domesticated animals and other novel disease vectors.
Eventually, the trend toward shorter stature reversed, and average heights for most populations began increasing. The trend is especially notable in the developed world during the past 75 years, following the industrialization of food systems.
“Culturally, we’re agricultural chauvinists. We tend to think that producing food is always beneficial, but the picture is much more complex than that,” says Emory anthropologist George Armelagos, co-author of the review. “Humans paid a heavy biological cost for agriculture, especially when it came to the variety of nutrients. Even now, about 60 percent of our calories come from corn, rice and wheat.”
"Humans paid a heavy biological cost for agriculture," says anthropologist George Armelagos. (Credit: iStockphoto.com.)
In 1984, Armelagos and M. N. Cohen wrote a groundbreaking book, “Paleopathology at the Origins of Agriculture,” which drew from more than 20 studies to describe an increase in declining health and nutritional diseases as societies shifted from foraging to agriculture.
The book was controversial at the time, but the link between the agricultural transition and declining health soon became widely accepted in what was then the emerging field of bioarcheology.
The current review was undertaken to compare data from more recent studies involving different world regions, crops and cultures. The studies included populations from areas of China, Southeast Asia, North and South America and Europe. All of the papers used standardized methods for assessing health at the individual level and examined how stressors were exhibited within the entire skeleton, rather than a concentration on a particular skeletal element or condition.
“Unless you’re considering a complete skeleton, you’re not getting a full picture of health,” Mummert says. “You could have an individual with perfect teeth, for example, but serious markers of infection elsewhere. You could see pitting on the skull, likely related to anemia or nutritional stress, but no marks at all on the long bones.”
Adult height, dental cavities and abscesses, bone density and healed fractures are some of the markers used to try to paint a more complete picture of an individual’s health.
“Bones are constantly remodeling themselves,” Mummert says. “Skeletons don’t necessarily tell you what people died of, but they can almost always give you a glimpse into their ability to adapt and survive.”
While the review further supports the link between early agricultural practices and declining stature and health, it’s important to keep re-evaluating the data as more studies are completed, Mummert says.
"Even now, about 60 percent of our calories come from corn, rice and wheat," Armelagos says. (Credit: iStockphoto.com.)
One confounding factor is that agriculture was not adopted in an identical fashion and time span across the globe. In some ancient societies, such as those of the North American coasts, crops may have merely supplemented a seafood diet. “In these cases, a more sedentary lifestyle, and not necessarily agriculture, could have perpetuated decreased stature,” Mummert says.
The way the human body adapted to changes we made in the environment 10,000 years ago could help us understand how our bodies are adapting now, she says.
Some economists and other scientists are using the rapid physiological increases in human stature during the 20th century as a key indicator of better health.
“I think it’s important to consider what exactly ‘good health’ means,” Mummert says. “The modernization and commercialization of food may be helping us by providing more calories, but those calories may not be good for us. You need calories to grow bones long, but you need rich nutrients to grow bones strong.”
Croatia does not have a reputation as a hotbed of ancient agriculture. But new excavations, described January 7 in San Antonio at the annual meeting of the Archaeological Institute of America, unveil a Mediterranean Sea -- hugging strip of southern Croatia as a hub for early farmers who spread their sedentary lifestyle from the Middle East into Europe.
Farming villages sprouted swiftly in this coastal region, called Dalmatia, nearly 8,000 years ago, apparently with the arrival of Middle Easterners already adept at growing crops and herding animals, says archaeologist Andrew Moore of Rochester Institute of Technology in New York.
Moore codirects an international research team, with archaeologist Marko Mendušic of Croatia’s Ministry of Culture in Šibenik, that has uncovered evidence of intensive farming at Pokrovnik and Danilo Bitinj, two Neolithic settlements in Dalmatia. Plant cultivation and animal raising started almost 8,000 years ago at Pokrovnik and lasted for close to a millennium, according to radiocarbon dating of charred seeds and bones from a series of occupation layers. Comparable practices at Danilo Bitinj lasted from about 7,300 to 6,800 years ago.
"Farming came to Dalmatia abruptly, spread rapidly and took hold immediately," Moore says.
Other evidence supports a fast spread of sophisticated farming methods from the Middle East into Europe (SN: 2/5/05, p. 88), remarks Harvard University archaeologist Ofer Bar-Yosef. Farming villages in western Greece date to about 9,000 years ago, he notes. Middle Eastern farmers exploited a wide array of domesticated plants and animals by 10,500 years ago, setting the stage for a westward migration, Bar-Yosef says.
Other researchers began excavating Pokrovnik and Danilo Bitinj more than 40 years ago. Only Moore and his colleagues dug deep enough to uncover signs of intensive farming.
Their discoveries support the idea that agricultural newcomers to southern Europe built villages without encountering local nomadic groups, Moore asserts. Earlier excavations at Neolithic sites in Germany and France raise the possibility that hunter-gatherers clashed with incoming villagers in northern Europe, he notes.
Surprisingly, Pokrovnik and Danilo Bitinj residents grew the same plants and raised the same animals, in the same proportions, as today’s Dalmatian farmers do, Moore says. Excavated seeds and plant parts show that ancient villagers grew nine different domestic plants -- including emmer, oats and lentils -- and gathered blackberries and other wild fruits.
Animal bones found at the two villages indicate that residents primarily herded sheep and goats, along with some cattle and a small number of pigs.
Diverse food sources provided a hedge against regional fluctuations in rainfall and growing seasons, according to Moore. "This is an astonishing demonstration of agricultural continuity from the Neolithic to present times," he says.
Aside from farming, Neolithic villagers in Dalmatia were "oriented toward the sea, and enjoyed extensive long-distance contacts," Moore adds. Chemical analyses of obsidian chunks found at Pokrovnik and Danilo Bitinj, directed by archaeologist Robert Tykot of the University of South Florida in Tampa, trace most of them to Lipari, an island off Sicily’s north coast.
Shapes and styles of pottery from the ancient Dalmatian villages changed dramatically several times during the Neolithic. Moore’s team can’t explain why these shifts occurred while the farming economy remained the same.
Other than three children found in separate graves, the researchers have unearthed no human skeletons at Pokrovnik and Danilo Bitinj.
“But early agriculturalists experienced nutritional deficiencies and had a harder time adapting to stress, probably because they became dependent on particular food crops, rather than having a more significantly diverse diet,” Mummert said.
“Culturally, we’re agricultural chauvinists. We tend to think that producing food is always beneficial, but the picture is much more complex than that,” says Emory anthropologist George Armelagos, professor of anthropology and co-author of the study.
Starting around 10,000 years ago, and continuing to relatively recently, no matter where and what crop, the pattern was the same. Agriculture led to shorter, less healthy people.
The spread of disease in concentrated settlements, as well as transmission of diseases from animals may have also played a part.
Gradually the trend reversed, especially after the dawn of mechanized agriculture in the developed world about 75 years ago, noted the authors.
“This broad and consistent pattern holds up when you look at standardized studies of whole skeletons in populations,” Mummert said.
Mummert reviewed literature studying factors like adult height, dental cavities and abscesses, bone density, healed fractures, and other indicators of health from populations around the world as they started farming. The populations came from far-flung areas of the globe, including China, Southeast Asia, North and South America, and Europe.
In 1968, William Guad, the director of the United States Agency for International Development (USAID) at the time, coined the term “the green revolution” when describing a series of agricultural advancements that prompted increased crop yields across the planet.
The revolution was much greener than Guad could have imagined, according to a new study in the journal Proceedings of the National Academy of Sciences.
Jennifer Burney, a scientist at Stanford University, lead a research team that looked at greenhouse gas emissions from modern agriculture, which currently contributes to around 12 percent of total global carbon dioxide emissions.
The researchers then calculated how much CO2 would have been released if the green revolution had not happened, but farmers were using more primitive methods to produce today’s amount of crops.
Before more efficient farming methods were invented, farmers relied on a simple technique for increasing production: acquiring more land. Clearing forests and other vegetation by burning them.
This method was easy and cheap, but it released huge amounts of greenhouse gases like methane, nitrous oxide and carbon dioxide into the atmosphere. By developing high-yield agricultural techniques, farmers avoided burning up loads of natural landscapes and in recent decades saved up to 590 billion metric tons of carbon dioxide from being released into the atmosphere.
“Our results dispel the notion that modern intensive agricultural is inherently worse for the environment than a more ‘old-fashioned’ way of doing things,” Burney said.
“Bones are constantly remodeling themselves,” Mummert said. “Skeletons don’t necessarily tell you what people died of, but they can almost always give you a glimpse into their ability to adapt and survive.”
“Humans paid a heavy biological cost for agriculture, especially when it came to the variety of nutrients. Even now, about 60 percent of our calories come from corn, rice and wheat,” said Armelagos.
Carbon dioxide deserves most of the blame for trapping heat in the Earth's atmosphere, but it has accomplices. The third most common greenhouse gas in the atmosphere is nitrous oxide, which is about 300 times more effective at trapping heat than carbon dioxide.
The majority of the world's nitrous oxide emissions come from agriculture in the U.S. But researchers at the University of Missouri – Columbia have found a way to limit the greenhouse gas without making farmer's lives more difficult. In fact the technique can also help farmers save money and improve their yields.
SEE ALSO: Better Than Farmville: A Simulated Century of Farming
“The main goal for our team has been to identify agricultural practices that maintain or increase production while reducing the environmental impact,” said Peter Motavalli of the University of Missouri.
In the past, most farmers tilled whole fields, but that caused tremendous problems with erosion. The Dust Bowl was largely caused by over-tilling the easily eroded soils of the Great Plains. To avoid the fate of the Joad family in John Steinbeck's The Grapes of Wrath, American farmers changed their practices to better conserve the soil.
Now, many farmers do not till their fields, but this increases fertilizer run-off. Also, when soil bacteria finds a tasty combination of nitrogen fertilizer and oxygen on the surface, they eat it up and release nitrous oxide.
The university researchers experimented with the technique of tilling strips of the field about a foot wide and eight to nine inches deep. This allows farmers to use less gas in their tractors while still leaving crop residues, like corn stalks, on the field's surface to prevent erosion.
SEE ALSO: Potential Biofuel Cropland Plentiful
When farmers till strips and apply fertilizer into the soil of the furrows, the nitrogen fertilizers don't run off and pollute waterways. It also improves yield since more fertilizer gets to the plants.
Here's where the climate benefits come in. By placing the nitrogen fertilizer into the furrows, less of the chemical is converted into nitrous oxide by air-breathing soil microbes.
SEE ALSO: Biofuel Grasslands For the Birds
The researchers conducted their study in northeast Missouri from 2008 to 2010. One field was “strip tilled” with nitrogen fertilizer placed in a band in the soil, while another field was left untilled with a surface application of nitrogen fertilizer.
The idea that agriculture led to a decline in health was pioneered by Armelos and M. N. Cohen back in 1984 in the book Paleoanthropology at the Origins of Agriculture. Though it was controversial at the time, the idea is now widely accepted.
This new study shows how widespread the link between agriculture and declining health was, and gathers into one place the numbers to back-up the assertion.
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