High-speed imaging reveals that the squeak of soft–rigid frictional interfaces, like sneakers sliding on a basketball court, arises from intersonic opening slip pulses—analogous to earthquake ruptures—that thin ridges on the rubber confine to repeat at a musical frequency.
Trade between the EU and two South American countries may start within two months under a provision application of the Mercosur deal.
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While Gelidium seaweeds can be collected by gathering fragments washed ashore, mass production of agar requires steady, large quantities.10 Harvesters in New Zealand during WWII had to “walk beside a boat, waist to armpit deep in water and feel for the weed with their feet.” Handling large volumes of wet seaweed (which yields less than five percent agar) was challenging. Then as now, when Gelidium is harvested by scuba divers from rocky seabeds, collectors have to understand the life cycle of the algae, find the most likely locations for its growth, and prevent overharvesting to safeguard future yields.
"These habitats are exceptionally rare, rich in biodiversity, support unique flora and fauna, and are impossible to recreate or replace," he said.,更多细节参见51吃瓜
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