Tag Archives: shape

How Evolution Shapes the Geometries of Life

COLLEGE PARK, Md. – Why does a mouse’s heart beat about the same number of times in its lifetime as an elephant’s, although the mouse lives about a year, while an elephant sees 70 winters come and go? Why do small plants and animals mature faster than large ones? Why has nature chosen such radically different forms as the loose-limbed beauty of a flowering tree and the fearful symmetry of a tiger?

These questions have puzzled life scientists since ancient times. Now an interdisciplinary team of researchers from the University of Maryland and the University of Padua in Italy propose a thought-provoking answer based on a famous mathematical formula that has been accepted as true for generations, but never fully understood. In a paper published the week of Feb. 17, 2014 in the Proceedings of the National Academy of Sciences, the team offers a re-thinking of the formula known as Kleiber’s Law. Seeing this formula as a mathematical expression of an evolutionary fact, the team suggests that plants’ and animals’ widely different forms evolved in parallel, as ideal ways to solve the problem of how to use energy efficiently. (more…)

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NASA Releases Radar Movie of Asteroid 2012 DA14

An initial sequence of radar images of asteroid 2012 DA14 was obtained on the night of Feb. 15/16, 2013, by NASA scientists using the 230-foot (70-meter) Deep Space Network antenna at Goldstone, Calif. Each of the 72 frames required 320 seconds of data collection by the Goldstone radar.

The observations were made as the asteroid was moving away from Earth. The asteroid’s distance from the radar dish increased from 74,000 miles (120,000 kilometers) to 195,000 miles (314,000 kilometers). The resolution is 13 feet (four meters) per pixel. The images span close to eight hours and clearly show an elongated object undergoing roughly one full rotation. The images suggest that the asteroid has a long axis of about 130 feet (40 meters). The radar observations were led by scientists Lance Benner and Marina Brozovic of NASA’s Jet Propulsion Laboratory, Pasadena, Calif. Additional Goldstone radar observations are scheduled on February 18, 19 and 20. (more…)

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Entropy Can Lead to Order, Paving The Route to Nanostructures

ANN ARBOR, Mich.— Researchers trying to herd tiny particles into useful ordered formations have found an unlikely ally: entropy, a tendency generally described as “disorder.”

Computer simulations by University of Michigan scientists and engineers show that the property can nudge particles to form organized structures. By analyzing the shapes of the particles beforehand, they can even predict what kinds of structures will form.

The findings, published in this week’s edition of Science, help lay the ground rules for making designer materials with wild capabilities such as shape-shifting skins to camouflage a vehicle or optimize its aerodynamics. (more…)

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When Cells Hit the Wall: UCLA Engineers Put The Squeeze on Cells to Diagnose Disease

If you throw a rubber balloon filled with water against a wall, it will spread out and deform on impact, while the same balloon filled with honey, which is more viscous, will deform much less. If the balloon’s elastic rubber was stiffer, an even smaller change in shape would be observed.

By simply analyzing how much a balloon changes shape upon hitting a wall, you can uncover information about its physical properties.

Although cells are not simple sacks of fluid, they also contain viscous and elastic properties related to the membranes that surround them; their internal structural elements, such as organelles; and the packed DNA arrangement in their nuclei. Because variations in these properties can provide information about cells’ state of activity and can be indicative of diseases such as cancer, they are important to measure. (more…)

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