X-ray reflectivity (XRR) is a powerful and popular scattering technique that can give valuable insight into the growth behavior of thin films. This study shows how a simple artificial neural network model can be used to determine the thickness, roughness and density of thin films of different organic semiconductors [diindenoperylene, copper(II) phthalocyanine and α-sexithiophene] on silica from their XRR data with millisecond computation time and with minimal user input or a priori knowledge. For a large experimental data set of 372 XRR curves, it is shown that a simple fully connected model can provide good results with a mean absolute percentage error of 8–18% when compared with the results obtained by a genetic least mean squares fit using the classical Parratt formalism. Furthermore, current drawbacks and prospects for improvement are discussed.

A new study published in the Feb. 2 issue of the Proceedings of the National Academy of Sciences indicates that forests in the Eastern United […]

The post Smithsonian ecologists discover forests are growing at a faster rate appeared first on Smithsonian Insider.

The stars move quickly because they are very close to each other, separated by only about one-fourth the distance from the Earth to the Moon. As a result, they share strong gravitational forces. They were once farther apart but have spiraled closer together over time. Billions of years from now, they will crash together and merge.

The post At 1,500,000 mph, twin stars in the constellation Cancer win speediest orbit award appeared first on Smithsonian Insider.

"This galaxy cluster wins the heavyweight title. It's among the most massive clusters ever found at this distance," said Mark Brodwin, a Smithsonian astronomer at the Harvard-Smithsonian Center for Astrophysics.

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The awarded film features STRI marine biologist Héctor M. Guzman diving with a group of five whale sharks while traveling in the Tropical Eastern Pacific. In the video, Guzmán tags a radiotransmitter to one of the sharks in order to follow its voyages.

The post Whale sharks featured in award-winning documentary following the work of Tropical Research Institute’s Héctor Guzman appeared first on Smithsonian Insider.


They found that the molars of fruit-eating species had sharp outer edges that likely allow them to pierce tough fruit skin and pulp... By contrast, the molars of insect-eating species were less complex, possibly because of their smoother shearing surfaces.

The post From chewing tough insects to soft fruit, bat teeth are highly specialized appeared first on Smithsonian Insider.

Molynocoelia erwini, is a new species of fruit fly from Ecuador recently described by USDA entomologist Allen Norrbom, who works in the Systematic Entomology Laboratory […]

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The fastest wind ever discovered blowing off a disk around a stellar-mass black hole has been observed by a team of astronomers using NASA’s Chandra X-ray Observatory.

The post Chandra X-ray Observatory clocks stellar wind at 20 million mph appeared first on Smithsonian Insider.

On the Origin of Species by Charles Darwin, 1859 This week’s Smithsonian Snapshot marks the May 11, 1820, anniversary of the launch of HMS Beagle, the […]

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More than 70 scientists from 9 institutions including the Smithsonian Tropical Research Institute, sequenced the entire genome of the butterfly genus Heliconius, a brightly colored favorite of collectors and scientists since the Victorian era.

The post Heliconius butterfly genome explains wing pattern diversity appeared first on Smithsonian Insider.

Ants dominate the earth’s ecosystems and many are voracious predators that use their mandibles and sheer numbers to pin down and tear apart most other […]

The post Carabidae in the colony, seven new beetles that bunk with ants: Q&A with Terry Erwin appeared first on Smithsonian Insider.

What crunchy food did Americans spend $5.5 billion on last year—with sales that spiked before snow and ice storms? If you guessed birdseed then you […]

The post Simple tips to keep your backyard birds healthy this winter appeared first on Smithsonian Insider.

You watch the weather forecast, gear up with hat, coat, scarf and gloves, but you still get cold after just a short time in the […]

The post Keeping Warm in Winter is for the Birds appeared first on Smithsonian Insider.

The majority of stars in our galaxy come in pairs. In particular, the most massive stars usually have a companion. These fraternal twins tend to […]

The post Mismatched Twin Stars Spotted in the Delivery Room appeared first on Smithsonian Insider.

On September 14, 2015, the Laser Interferometer Gravitational-wave Observatory (LIGO) detected gravitational waves from the merger of two black holes 29 and 36 times the […]

The post Ligo’s Twin Black Holes Might Have Been Born Inside a Single Star appeared first on Smithsonian Insider.

Every few thousand years, an unlucky star wanders too close to the black hole at the center of the Milky Way. The black hole’s powerful […]

The post Our Galaxy’s Black Hole is Spewing Planet-size “Spitballs” appeared first on Smithsonian Insider.

Only the Wing is a new book by Russell Lee that recounts Horten's epic quest to stabalize and control the all-wing aircraft.

The post New Book: “Only the Wing: Reimar Horten’s Epic Quest to Stabilize and Control the All-Wing Aircraft” appeared first on Smithsonian Insider.

Now, for the first time, Charles Darwin's life is portrayed pictorially in an illustrated biography in graphic novel-style for all ages to enjoy.

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Imke K. Mandemaker, Di Zhou, Serena T. Bruens, Dick H. Dekkers, Pernette J. Verschure, Raghu R. Edupuganti, Eran Meshorer, Jeroen A. Demmers, and Jurgen A. Marteijn

Many chromatin remodeling and modifying proteins are involved in the DNA damage response by stimulating repair or inducing DNA damage signaling. Interestingly, here we identified that down regulation of the H1-interacting protein SET results in increased resistance to a wide variety of DNA damaging agents. We found that this increased resistance is not the result of an inhibitory effect of SET on DNA repair, but rather the consequence of a suppressed apoptotic response to DNA damage. We further provide evidence that the histone chaperone SET is responsible for the eviction of H1 from chromatin. Knock down of H1 in SET-depleted cells resulted in re-sensitization of cells to DNA damage, suggesting that the increased DNA damage resistance in SET-depleted cells is the result of enhanced retention of H1 on chromatin. Finally, clonogenic survival assays show that SET and p53 are epistatic in attenuating DNA damage-induced cell death. Altogether, our data show a role for SET in the DNA damage response as a regulator of cell survival following genotoxic stress.

Smithsonian Institution Libraries has recently acquired a rare first edition of Darwin's Geological Observations on the Volcanic Islands, Visited During the Voyage of the H.M.S. Beagle.

The post With 1844 first edition, Smithsonian Libraries completes its collection of Charles Darwin’s three-volume geology series appeared first on Smithsonian Insider.

The prehistoric Xenicibis used its wings like two clubs hinged at the wrist joint in order to swing at and attack one another.

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