Posts Tagged ‘Green Revolution’
“It’s the bell curve again”*…
Joseph Howlett on how the central limit theorem, which started as a bar trick for 18th-century gamblers, became something on which scientists rely every day…
No matter where you look, a bell curve is close by.
Place a measuring cup in your backyard every time it rains and note the height of the water when it stops: Your data will conform to a bell curve. Record 100 people’s guesses at the number of jelly beans in a jar, and they’ll follow a bell curve. Measure enough women’s heights, men’s weights, SAT scores, marathon times — you’ll always get the same smooth, rounded hump that tapers at the edges.
Why does the bell curve pop up in so many datasets?
The answer boils down to the central limit theorem, a mathematical truth so powerful that it often strikes newcomers as impossible, like a magic trick of nature. “The central limit theorem is pretty amazing because it is so unintuitive and surprising,” said Daniela Witten, a biostatistician at the University of Washington. Through it, the most random, unimaginable chaos can lead to striking predictability.
It’s now a pillar on which much of modern empirical science rests. Almost every time a scientist uses measurements to infer something about the world, the central limit theorem is buried somewhere in the methods. Without it, it would be hard for science to say anything, with any confidence, about anything.
“I don’t think the field of statistics would exist without the central limit theorem,” said Larry Wasserman, a statistician at Carnegie Mellon University. “It’s everything.”
Perhaps it shouldn’t come as a surprise that the push to find regularity in randomness came from the study of gambling…
Read on for the fascinating story of: “The Math That Explains Why Bell Curves Are Everywhere,” from @quantamagazine.bsky.social.
Howlett concludes by observing that “The central limit theorem is a pillar of modern science, ultimately, because it’s a pillar of the world around us. When we combine lots of independent measurements, we get clusters. And if we’re clever enough, we can use those clusters to find out something interesting about the processes that made them”– which follows from the story he shares.
Still, we’d do well to remember that there are limits to its applicability, both descriptively (as Nassim Nicholas Taleb points out, “because the bell curve ignores large deviations, cannot handle them, yet makes us confident that we have tamed uncertainty”) and prescriptively (as Benjamim Bloom argues, “The bell-shaped curve is not sacred. It describes the outcome of a random process. Since education is a purposeful activity….the achievement distribution should be very different from the normal curve if our instruction is effective).
For (much) more, see Peter Bernstein‘s wonderful Against the Gods: The Remarkable Story of Risk
* Robert A. Heinlein, Time Enough for Love
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As we noodle on the normal distribution, we might send curve-shattering birthday greetings to Norman Borlaug; he was born on ths date in 1914. An agronomist, he developed and led initiatives worldwide that contributed to the voluminous increases in agricultural production we call “the Green Revolution.” Borlaug was awarded multiple honors for his work, including the Nobel Peace Prize, the Presidential Medal of Freedom, and the Congressional Gold Medal; he’s one of only seven people to have received all three of those awards.
“It’s not a bug, it’s a feature”*…
Anna Marija Helt reports that, as global warming challenges tradtional agriculture, scientists are looking to “probiotics” for crops as a new green revolution in agriculture…
Potatoes contain something about which most people are entirely unaware: endophytes, which means “within plants.” Endophytes can also be found in other vegetables, fruits, and grains. In fact, all plants harbor endophytes in the form of bacteria, fungi, and other microbes.
Endophytes eat plant-derived nutrients but typically don’t cause disease. Instead, they bolster plant growth, disease resistance, antioxidant status, or tolerance to stressors such as drought, heat, and cold. Endophytes enable plants to respond quickly to such stressors by expanding their genetic repertoire, according to a review by ecologist Christine Hawkes and colleagues. To improve crop health and sustainability, Hawkes studies how plants, their fungal residents, and such stressors interact.
Given climate-related drought and temperature extremes, declining soil quality, and a decrease in arable land, endophytes, argue Pankaj Trivedi, Chakradhar Mattupalli, Kellye Eversole, and Jan E. Leach, might undergird a sustainable “green revolution” to improve agricultural productivity while lessening reliance on environmentally damaging and health-threatening agricultural chemicals. Endophytes can have an impact, says plant biotechnologist Julissa Ek-Ramos, on “climate change, recovering the soil, and having more healthy food to eat.”…
… “It’s really amazing how strongly these endophytes can combat the fungal pathogens of crops,” [microbiologist Sharon] Doty says. And she notes regarding their growth-promoting effects, “It works in maize, in rice, in tomatoes, in bell peppers, and strawberries.” Her team has also isolated endophytes from sweet potatoes that improve the rooting of poplars, a promising biofuels crop.
Endophytes confer additional traits useful for a changing planet. For example, those from geothermal habitats can confer heat tolerance, based on studies led by geneticist Regina Redman. And crop physiologist K. M. Manasa demonstrated salt-tolerance in rice plants inoculated with an endophyte from seaside plants. Rice is salt-sensitive and one of the world’s main food crops. But increasing soil salinity is impacting a fifth of farmable land globally due to climate change and human water and land use practices…
Nitrogen is often the most limiting soil nutrient for crops, something nineteenth-century farmers recognized. Agronomist and Nobel Prize nominee Johanna Döbereiner discovered nitrogen-fixing endophytes in non-legume plants in the twentieth century that, like rhizobia, might reduce the need for financially and environmentally costly synthetic fertilizers. Many of the endophytes Doty has characterized over twenty-five years fix nitrogen and promote growth in lab, greenhouse, and field trials but have a much broader host range than rhizobia, extending from farm lands to forests…
… Developing real-world endophyte applications is a complicated challenge, but a necessary one given the need for more productive and sustainable agriculture. In the meantime, skeptical farmers are getting onboard.
“There’s a lot of conversations going on between researchers and farmers,” says Friesen, to “move the needle on our understanding of these processes that are so important for soil health but also plant health and the stability and security of our food supply.”…
More at “Better Farming Through Endophytes,” from @ahelt.bsky.social in @jstordaily.bsky.social.
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As we muse on microbes, we might send healthy birthday greetings to John Boyd Orr (1st Baron Boyd-Orr); he was born on this date in 1880. A teacher, medical doctor, biologist, nutritional physiologist, politician, businessman, and farmer, he was awarded the Nobel Peace Prize in 1949 for his scientific research into nutrition and for his work as the first Director-General of the United Nations Food and Agriculture Organization.
“Optimism is the madness of insisting that all is well when we are miserable”*…
By the end of last year, anyone who had been paying even passing attention to the news headlines was highly likely to conclude that everything was terrible, and that the only attitude that made sense was one of profound pessimism – tempered, perhaps, by cynical humour, on the principle that if the world is going to hell in a handbasket, one may as well try to enjoy the ride… Yet one group of increasingly prominent commentators has seemed uniquely immune to the gloom…
The loose but growing collection of pundits, academics and thinktank operatives who endorse this stubbornly cheerful, handbasket-free account of our situation have occasionally been labelled “the New Optimists”, a name intended to evoke the rebellious scepticism of the New Atheists led by Richard Dawkins, Daniel Dennett and Sam Harris. And from their perspective, our prevailing mood of despair is irrational, and frankly a bit self-indulgent. They argue that it says more about us than it does about how things really are – illustrating a certain tendency toward collective self-flagellation, and an unwillingness to believe in the power of human ingenuity. And that it is best explained as the result of various psychological biases that served a purpose on the prehistoric savannah – but now, in a media-saturated era, constantly mislead us…
Don’t worry, be happy? “Is the world really better than ever?”
* Voltaire
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As we cultivate our gardens, we might send well-watered birthday greeting to Monkombu Sambisivan Swaminathan; he was born on this date in 1925. A geneticist and international administrator, he is known as the “Indian Father of Green Revolution” for his leadership and success in introducing and further developing high-yielding varieties of rice and wheat in India. Swaminathan, based these days at he MS Swaminathan Research Foundation, is an advocate of moving India to sustainable development, especially using environmentally-sustainable agriculture, sustainable food security, and the preservation of biodiversity– which he calls an “evergreen revolution.”
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