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Reference Terms
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UV index

The UV index is an international standard measurement of how strong the ultraviolet (UV) radiation from the sun is at a particular place on a particular day. Its purpose is to help people to effectively protect themselves from UV light, which causes sunburns, eye damage such as cataracts, skin aging, and skin cancer (see the section health effects of ultraviolet light). Public-health organizations recommend that people protect themselves (for example, by wearing sunscreen and a hat) when the UV index is 3 or higher.

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Health & Medicine News

September 16, 2026

Scientists have discovered that some severe genetic disorders linked to rapid aging may be driven not just by damaged DNA, but by the body’s overreaction to that damage. When broken DNA fragments leak into the wrong part of a cell, an immune ...
Eating four to six servings of whole grains a day may deliver meaningful benefits for heart health, according to a large review of 87 clinical trials. Researchers found improvements in body weight, waist size, blood pressure, cholesterol, blood ...
Eating more ultra-processed foods was linked to greater fat buildup inside thigh muscles, according to MRI scans of 615 adults at risk for knee osteoarthritis. Surprisingly, the association remained ...
A naturally occurring molecule called erucamide may help the retina fight back against diseases that cause progressive vision loss. Restoring the molecule activated protective immune responses that helped stabilize retinal tissue and slow aspects of ...
Older adults who changed the balance of fat, carbohydrates, and animal protein in their diets showed signs of reduced biological age after just four weeks. The strongest result appeared in participants eating an omnivorous, lower-fat, ...
Simply smelling chocolate helped men complete more leg extension repetitions without making the workout feel harder, with dark chocolate producing the strongest effect. The researchers think familiar food aromas may influence appetite and motivation ...
Scientists have uncovered sweeping changes in how the human brain controls and organizes its genome beginning in midlife, offering new clues to why aging sharply increases the risk of Alzheimer’s and other neurodegenerative diseases. One of the ...
The flesh eating New World screwworm has returned to the United States, threatening livestock, wildlife, pets and potentially people as it spreads north. A new UC San Diego tracking system aims to predict where the parasite could strike next while ...
A major analysis of 139 clinical trials involving nearly 10,000 people suggests that some of the simplest treatments may work best for knee osteoarthritis. Knee braces ranked highest overall for ...
A newly discovered communication system in the microscopic “antennae” of cells may help explain how some congenital heart defects develop. When genetic mutations disrupt this system, the effects ...
Ancient DNA reveals that plague was already killing hunter-gatherers in Siberia 5,500 years ago, long before cities and flea-driven epidemics. The prehistoric strains may have been especially ...
Cancer rates are rising in adults under 55, and new research suggests accelerated biological aging may be one piece of the puzzle. Scientists found that people from more recent generations tended to ...

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