Mike Meetz and Sam Wormley team up to provide a lively
discussion with OLLI members about science in the news. A
deep understanding of science is not required to share and
discuss recent Science in the News. Past Classes.
⓵ It’s leaf-peeping season. Has this year’s extreme weather
hurt fall foliage?
https://www.scientificamerican.com/article/how-a-year-of-extreme-weather-and-a-super-el-nino-will-affect-fall-foliage/
When summer turns to fall, trees get less sunlight, and they
slowly stop photosynthesizing to conserve water and
nutrients for the winter. At the same time, many trees suck
up chlorophyll from their leaves, revealing yellow shades.
(Chlorophyll creates the green pigment in leaves and holds
lots of valuable nutrients.) Some trees, such as maples,
also produce new, red pigments called anthocyanins in the
fall that protect them as they’re absorbing nutrients.
This whole process is designed to conserve as much
chlorophyll as possible, says Christy Rollinson, a forest
ecologist at the Morton Arboretum in Illinois. “Green is
really expensive—not just in my wallet but in the tree’s
wallet as well,” she says. “All of these different colors
are related to the tree trying to protect the green.”
As the climate warms, it can cause trees to extend their
growing season, and warm evenings don’t trap fall colors in
the leaves as well as colder ones, meaning later and less
vibrant changes to foliage. Extreme weather events, such as
drought or heavy rainfall, also stress trees and can trigger
them to rapidly protect themselves by more rapidly pulling
in the chlorophyll from their leaves, dulling fall colors.
Just as leaves that fall from different trees have distinct
shapes and hues of crimson or gold, tree species vary in how
susceptible they are to weather. Sugar maples, a “superstar”
of New England leaf peeping, are extremely sensitive to
temperature and precipitation, Finton says. Oak trees, on
the other hand, are more tolerant. But there’s a lot that
scientists still don’t understand about how different trees
are affected.
⓶ Same Calories, Same Nutrients - but One Meal Triggered a
Surprising Reaction in the Body
https://scitechdaily.com/same-calories-same-nutrients-but-one-meal-triggered-a-surprising-reaction-in-the-body/
Ultraprocessed foods supply more than half of the average
American’s daily calories, and their place in diets
worldwide is growing. Formulated to be convenient,
accessible, affordable, and highly palatable, they can be
easy to overeat. Understanding their effects on health,
however, requires untangling the influence of processing
from that of the nutrients they contain.
Meals with the same basic nutritional profile are generally
expected to affect blood sugar in similar ways. Yet in a
Virginia Tech study, healthy adults expended more energy and
burned less carbohydrate after eating an ultraprocessed meal
than after a minimally processed one. Both meals contained
300 calories and were closely matched for carbohydrates,
fat, protein, water, salt, and weight. The findings appeared
in Nature Metabolism.
Related
Healthy Food vs. Highly Processed Food: What to Know
https://www.healthline.com/nutrition/junk-food-vs-healthy-food
Mediterranean Diet (Science and Recipes)
http://edu-observatory.org/olli/Mediterranean/index.html
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Related Material from some recent OLLI courses
http://edu-observatory.org/olli/classes.html
Alan Lightman On Richard Feynman's Amazing Mind, Or How
"Hawking Radiation" Could Well Be "Feynman Radiation" (6min)
https://player.vimeo.com/video/104516539
sam.wormley@icloud.com