New synthetic polymer degradable under very mild acidic conditions

A new type of degradable synthetic polymer was prepared by Rh-catalyzed three-component polymerization of a bis(diazocarbonyl) compound, bis(1,3-diketone), and tetrahydrofuran. The resulting polymer was highly sensitive to mild acidic conditions and degraded into a combination of well-defined low molecular weight compounds. With this unique degradability, the polymer could be utilized as an environmentally friendly polymeric material.

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Faults' hot streaks and slumps could change earthquake hazard assessments

For more than a century, a guiding principle in seismology has been that earthquakes recur at semi-regular intervals according to a 'seismic cycle.' In this model, strain that gradually accumulates along a locked fault is completely released in a large earthquake. Recently, however, seismologists have realized that earthquakes often occur in clusters separated by gaps, and one research group now argues that the probability of a tremor's recurrence depends upon whether a cluster is ongoing — or over.

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Elusive compounds of greenhouse gas isolated

Nitrous oxide (N2O) is a potent atmospheric pollutant. Although naturally occurring, anthropogenic N2O emissions from intensive agricultural fertilization, industrial processes, and combustion of fossil fuels and biomass are a major cause for concern. Researchers have isolated elusive transition metal compounds of N2O that provide clues into how it could be used in sustainable chemical technologies.

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Geochemists measure new composition of Earth's mantle

Geochemists have investigated the volcanic rocks that build up the Portuguese island group of the Azores in order to gather new information about the compositional evolution of the Earth's interior. The results suggest that a larger amount of the Earth's mantle has melted and formed the Earth's crust than previously thought.

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