Tag Archives: carnegie institution

Forest model predicts canopy competition

Scientists use measurements from airborne lasers to gauge changes in the height of trees in the forest. Tree height tells them things like how much carbon is being stored. But what accounts for height changes over time — vertical growth or overtopping by a taller tree? A new statistical model helps researchers figure out what’s really happening on the ground.

PROVIDENCE, R.I. [Brown University] — Out of an effort to account for what seemed in airborne images to be unusually large tree growth in a Hawaiian forest, scientists at Brown University and the Carnegie Institution for Science have developed a new mathematical model that predicts how trees compete for space in the canopy. (more…)

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Mutual benefits: Stressed-out trees boost sugary rewards to ant defenders

ANN ARBOR — When water is scarce, Ecuador laurel trees ramp up their investment in a syrupy treat that sends resident ant defenders into overdrive, protecting the trees from defoliation by leaf-munching pests.

The water-stressed tropical forest trees support the production of more honeydew, a sugary excretion imbibed by the Azteca ants that nest in the laurels’ stem cavities. In return, ant colonies boost their numbers and more vigorously defend the life-sustaining foliage. (more…)

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Cosmochemist discovers potential solution to meteorite mystery

Chondrules may have formed from high-pressure collisions in early solar system

At issue is how numerous small, glassy spherules had become embedded within specimens of the largest class of meteorites—the chondrites. British mineralogist Henry Sorby first described these spherules, called chondrules, in 1877. Sorby suggested that they might be “droplets of fiery rain” which somehow condensed out of the cloud of gas and dust that formed the solar system 4.5 billion years ago. (more…)

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Moon and Earth have common water source

Researchers used a multicollector ion microprobe to study hydrogen-deuterium ratios in lunar rock and on Earth. Their conclusion: The Moon’s water did not come from comets but was already present on Earth 4.5 billion years ago, when a giant collision sent material from Earth to form the Moon.

PROVIDENCE, R.I. [Brown University] —Water inside the Moon’s mantle came from primitive meteorites, new research finds, the same source thought to have supplied most of the water on Earth. The findings raise new questions about the process that formed the Moon. (more…)

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World’s Longest-Running Plant Monitoring Program Now Digitized

Data from the research plots on Tumamoc Hill reveal changes in the Sonoran Desert and have been important to key advances in the science of ecology.

Researchers at the University of Arizona’s Tumamoc Hill have digitized 106 years of growth data on individual plants, making the information available for study by people all over the world.

Knowing how plants respond to changing conditions over many decades provides new insights into how ecosystems behave. (more…)

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Carbon’s role in atmosphere formation

A new study in Proceedings of the National Academy of Sciences suggests that the way carbon moves from within a planet to the surface plays a big role in the evolution of a planet’s atmosphere. If Mars released much of its carbon as methane, for example, it might have been warm enough to support liquid water.

PROVIDENCE, R.I. [Brown University] — A new study of how carbon is trapped and released by iron-rich volcanic magma offers clues about the early atmospheric evolution on Mars and other terrestrial bodies. (more…)

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Crystals for Efficient Refrigeration

Washington, D.C.-– Researchers at the Carnegie Institution have discovered a new efficient way to pump heat using crystals. The crystals can pump or extract heat, even on the nanoscale, so they could be used on computer chips to prevent overheating or even meltdown, which is currently a major limit to higher computer speeds. The research is published in the Physical Review Letters.

Ronald Cohen, staff scientist at Carnegie’s Geophysical Laboratory and Maimon Rose, originally a high school intern now at the University of Chicago carried out the research. They performed simulations on ferroelectric crystals—materials that have electrical polarization in the absence of an electric field. The electrical polarization can be reversed by applying an external electrical field. The scientists found that the introduction of an electric field causes a giant temperature change in the material, dubbed the electrocaloric effect, far above a temperature to a so-called paraelectric state. (more…)

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