Single-wavelength X-ray anomalous diffraction (SAD) is a frequently employed technique to solve the phase problem in X-ray crystallography. The precision and accuracy of recovered anomalous differences are crucial for determining the correct phases. Continuous rotation (CR) and inverse-beam geometry (IBG) anomalous data collection methods have been performed on tetragonal lysozyme and monoclinic survivin crystals and analysis carried out of how correlated the pairs of Friedel's reflections are after scaling. A multivariate Bayesian model for estimating anomalous differences was tested, which takes into account the correlation between pairs of intensity observations and incorporates the a priori knowledge about the positivity of intensity. The CR and IBG data collection methods resulted in positive correlation between I(+) and I(−) observations, indicating that the anomalous difference dominates between these observations, rather than different levels of radiation damage. An alternative pairing method based on near simultaneously observed Bijvoet's pairs displayed lower correlation and it was unsuccessful for recovering useful anomalous differences when using the multivariate Bayesian model. In contrast, multivariate Bayesian treatment of Friedel's pairs improved the initial phasing of the two tested crystal systems and the two data collection methods.

A mysterious nocturnal animal was leaving its tracks on the delicate mirrors of the telescopes at the Smithsonian's Whipple Observatory in Arizona. With a little ingenuity and a live trap, the mystery was solved. The visitor proved to be a ringtail cat, a member of the raccoon family.

The post Astronomers solve mystery of dusty foot trails crossing telescope mirrors appeared first on Smithsonian Insider.

When two red panda babies are born in critical condition at Smithsonian’s National Zoo, caretakers make the crucial decision to raise them by hand.

The post Raising red pandas by hand at the National Zoo appeared first on Smithsonian Insider.

Ollie the bobcat, who escaped from her enclosure at the Smithsonian National Zoo, was found two days after her disappearance roaming near the zoo’s bird […]

The post Missing bobcat found on zoo property appeared first on Smithsonian Insider.

When Smithsonian Tropical Research Institute paleobotanist Carlos Jaramillo learned that Panama was expanding its canal in 2006 and blasting 100 million tons of rock to […]

The post Using Fossils in Panama to Model Future Climate Change appeared first on Smithsonian Insider.

Tuvan ensemble Alash demonstrates various traditional throat singing styles that they use in their music. Smithsonian Folkways Recordings video.

The post Alash demonstrates throat singing styles appeared first on Smithsonian Insider.

The storage and flux of terrestrial carbon (C) is one of the most uncertain components of the global C budget and detailed quantification of forest […]

The post Remote sensing of a Smithsonian forest with airborne LiDAR appeared first on Smithsonian Insider.

Two grass species that had been relatively rare in the plots, Spartina patens and Distichlis spicata, began to respond vigorously to the excess nitrogen. Eventually the grasses became much more abundant. Nitrogen ultimately changed the composition of the ecosystem as well as its capacity to store carbon.

The post Scientists find excess nitrogen favors plants that respond poorly to rising CO2 appeared first on Smithsonian Insider.

The North Pole isn’t the only place on Earth affected by slight increases in temperature. Until recently, scientific thinking used to posit that tropical forests, […]

The post Rising temperatures mean more blooms for tropical rainforests appeared first on Smithsonian Insider.

Unless you’ve been living under a rock for the last few years, you’ve doubtless caught at least a passing reference to the plight of the […]

The post Discovery: Rising CO2 depletes pollen’s nutritional potency, bees suffer appeared first on Smithsonian Insider.

Coral reefs are home to some of the most colorful, diverse life on the planet. And yet, for all their fame as biodiversity hotspots, it’s […]

The post Coral reef eavesdropping unveils burrowed, romantic male singers appeared first on Smithsonian Insider.

Millions, if not billions, of specimens reside in the world’s natural history collections, but most of these have not been carefully studied, or even looked […]

The post Using digitized Botany specimens, AI excels in simple curatorial tasks appeared first on Smithsonian Insider.

In the first reported crystal structure involving the potential ligand N,N',N''-tris­(2-pyridin­yl)-1,3,5-benzene­tricarboxamide, inter­molecular N—H⋯O hydrogen bonds link the mol­ecules via their amide groups into slanted ladder-like chains. Only two of the three amide groups in the mol­ecule are involved in hydrogen bonding, which influences the degree of out-of-plane twisting at each amide group.

To date X-ray protein crystallography is the most successful technique available for the determination of high-resolution 3D structures of biological molecules and their complexes. In X-ray protein crystallography the structure of a protein is refined against the set of observed Bragg reflections from a protein crystal. The resolution of the refined protein structure is limited by the highest angle at which Bragg reflections can be observed. In addition, the Bragg reflections alone are typically insufficient (by a factor of two) to determine the structure ab initio, and so prior information is required. Crystals formed from an imperfect packing of the protein molecules may also exhibit continuous diffraction between and beyond these Bragg reflections. When this is due to random displacements of the molecules from each crystal lattice site, the continuous diffraction provides the necessary information to determine the protein structure without prior knowledge, to a resolution that is not limited by the angular extent of the observed Bragg reflections but instead by that of the diffraction as a whole. This article presents an iterative projection algorithm that simultaneously uses the continuous diffraction as well as the Bragg reflections for the determination of protein structures. The viability of this method is demonstrated on simulated crystal diffraction.

When creating a System Composer architecture model, if the following functions are called with an invalid or missing stereotype, it can cause the model to get corrupted and might lead to a MATLAB crash:

• addComponent
• addPort
• connect

If you try to open a text file with UTF-16 or UTF-32 encoding, the Import Tool displays a warning message stating that the encoding is not supported.  If you continue to load the file anyways, it is opened with UTF-8 encoding, and the file may not be displayed or imported as expected.This bug exists in the following release(s):
R2020a

This bug has a workaround

Interested in Upgrading?

The GDC Compliance Advisory Board (CAB) provides insight into how to interpret the Strong Consumer Authentication (SCA) mandate described in PSD 2 without jeopardizing data privacy concerns protected by GDPR. 

In the first reported crystal structure involving the potential ligand N,N',N''-tris(pyridin-2-yl)benzene-1,3,5-tricarboxamide, C24H18N6O3, intermolecular N—H...O hydrogen bonds link the molecules via their amide groups into slanted ladder-like chains, in which the uprights of the ladder are formed by the hydrogen-bonding interactions and the benzene ring cores of the molecules act as the rungs of the ladder. Only two of the three amide groups in the molecule are involved in hydrogen bonding and this influences the degree of out-of-plane twisting at each amide group, with the twist being more significant for those amide groups participating in hydrogen bonds.

During evaporation of natural and synthetic K–Mg–Cl brines, the formation of almost square plate-like crystals of potassium carnallite (potassium chloride magnesium dichloride hexa­hydrate) was observed. A single-crystal structure analysis revealed a monoclinic cell [a = 9.251 (2), b = 9.516 (2), c = 13.217 (4) Å, β = 90.06 (2)° and space group C2/c]. The structure is isomorphous with other carnallite-type com­pounds, such as NH4Cl·MgCl2·6H2O. Until now, natural and synthetic carnallite, KCl·MgCl2·6H2O, was only known in its ortho­rhom­bic form [a = 16.0780 (3), b = 22.3850 (5), c = 9.5422 (2) Å and space group Pnna].

A Nintendo Entertainment System.; Credit: Mark Ramsay/Flickr Creative Commons

There have been plenty of video game movies over the years, but there have been far fewer actually good ones. "Ready Player One," based on the 2011 video game-inspired novel, has the chance to be a great one thanks to the announcement that Steven Spielberg has signed on to direct.

That book was inspired by classic video games, and was written using classic video game cheats to play parts of classic games and write them into his book, author Ernest Cline said in a recent talk. That got us thinking about the classic video game cheats and secrets that stuck with us from our younger days playing classic video games — here's our top 11.

1. The Konami Code

Up up down down left right left right B A start! This code became such a part of video game culture that it got its own name. It was popularized in various games made by Konami, particularly Contra, leading to it also being known as the "Contra Code" for its ability to give you 30 lives in the game. Before the Internet, it was spread through gaming magazines and word of mouth — it was so influential that there are still developers who put it in their games. (There's even an entire Wikipedia page of games, both from Konami and others, that use the Konami Code. It's even been used on some websites.)

What is the Konami Code

2. Street Figher II Turbo's turbo

The game that I actually used a code for the most as a kid, the Super Nintendo code down, R, up, L, Y, B on the second controller didn't give you any advantages — it just kicked the speed up. By default, you had a few selections for how fast the game would be, but you could multiple that several-fold with this code, letting you and your friends battle at what at the time felt unbelievably fast.

3. Super Mario Bros.'s Minus World

This one doesn't involve a code, but players managed to discover what was deemed a glitch in the game that put you into a messed up version of another level, dubbed by fans the Minus World due to just "-1" instead of a full level number appearing at the top of the screen. There was no way to escape the glitched level, no matter how hard you might try, sending you to play it over and over again until your time ran out or you were killed by enemies. Still, modern players have found that you can go on thanks to various computer emulators and the like; see some of the worlds beyond below:

Minus World video

4. Metroid and Justin Bailey

Fans early on discovered that the password JUSTIN BAILEY allowed you to start with all of the available weapons along with plenty of life and ammo. Fans didn't know whether Justin Bailey was a reference to an actual person, just a code coincidence or something else, but that didn't stop them from eagerly playing through with this code. It also removed lead character Samus Aran from her armor, allowing players to discover that the game's star was an early female lead character, even if her armor didn't clue players in before the end of the game without the code.

Justin Bailey video

5. Doom's God mode

By typing the letters iddqd in PC game Doom, players could enable God mode, making them essentially invincible and letting them power through the early first-person shooter. The code had been available in developer id's earlier game Wolfenstein, but hadn't been quite as easily accessible. So, if you ever need a power boost when you're fighting on Mars, Doom has the answer. (Unfortunately, we don't believe this provides any extra protection for NASA's Mars rovers.)

6. Mortal Kombat's Reptile

The developers of Mortal Kombat made a battle against Reptile unbelievably hard for Mortal Kombat fans, including putting some randomness into whether doing what you were supposed to do to unlock the character would even work. Still, players happily pumped in extra quarters for the chance to face off against Reptile, a character with a look that mirrored that of characters Sub-Zero and Scorpion, just with a different color. Players had to achieve a Double Flawless victory on the Pit level, finish the match using their fatality move, and there also had to be a silhouette flying past the moon in the background — which only happened every sixth game.

Mortal Kombat: Reptile

7. The Legend of Zelda's Second Quest

The Legend of Zelda was a pretty challenging early adventure game, one of the first releases for the Nintendo home video game console. When you beat the game, you were given the option to go on a "Second Quest," which was a tweaked version of the game you just played except waaaaay harder. However, if you thought you were the coolest kid on the block and were so awesome you didn't need a warmup, you could name your character "ZELDA" (in one of the more obvious cheats in video game history) and skip ahead to that Second Quest from the start. You would then likely cry from how hard it was and start another new game with a different name.

8. NBA Jam's celebrity secret characters

A variety of celebrities from sports, music, and even politics were available by putting in various initials combined with buttons on the controller. These included then-President Bill Clinton, Al Gore, Warren Moon and more. That tradition has been continued in more recent NBA Jam games, with President Obama and others available for your video gaming pleasure.

9. GoldenEye's extra modes

There were a wide variety of cheat codes for GoldenEye, widely considered one of the all-time great first-person shooters. Sure, you could use codes to unlock different levels, but the reason these codes are remembered is because it gave you all sorts of new ways to play against your friends. The game also had an actual cheat menu that would appear if you accomplished one of a variety of goals, and from that menu you could cheat extra hard by using your controller to unlock things like a paintball mode, turbo mode, modes with both giant heads and teeny-tiny James Bonds and more.

10. Sonic The Hedgehog 2's Debug Mode

The Sonic debug mode is the perfect example of why so many games included cheats back in the day: They were often for the developers to be able to more easily play the games while looking for bugs and doing other testing. Sonic 2 let you get to an actual debug mode by playing various sounds from the level select screen (1, 9, 9, 2, 1, 1, 2, 4, for your reference), then pressing start and holding the A button. Developers later put them in for fun and intended them for the players to discover, but some of the early cheat codes were just meant for developers — but players proved more intrepid than they may have anticipated.

Sonic debug mode

11. Mike Tyson's Punch-Out: Go straight to Mike Tyson

There was actually a password mode in this game — before games had the option to save, plenty of games gave you codes that let you get back to where you were before. This is one of the examples from that darker time, where whether you played through opponents like Glass Joe and Bald Bull or not, you could try your changes against Lightning Mike (at least until the video game's license ran out and he was replaced in future editions with the way less exciting "Mr. Dream"). You better have had a pen and paper ready when your friend started yelling at you 007 373 5963 for you to use on your own copy of the game — no sharing. The game is hard enough that even Mike Tyson had some trouble fighting himself:

Mike Tyson vs. Mike Tyson

Let us know in the comments the classic video games — and the classic cheat codes and secrets — that inspired you.

This content is from Southern California Public Radio. View the original story at SCPR.org.

The analytical solution of the problem of X-ray spherical-wave Laue diffraction in a single crystal with a linear change of thickness on the exit surface is derived. General equations are applied to a specific case of plane-wave Laue diffraction in a thick crystal under the conditions of the Borrmann effect.

Using mineralogical data, it is demonstrated that chemical simplicity measured as an amount of Shannon information per atom on average corresponds to higher symmetry measured as an order of the point group of a mineral, which provides a modern formulation of the Fedorov–Groth law.

File photo: Lorne Street Elementary students had to grab books from a book bin after their library was closed during the recession.; Credit: Annie Gilbertson/KPCC

More than 200 Los Angeles Unified School District elementary school libraries have reopened in just two months, according to district officials.

Recession-era budget cuts had left many libraries without staffing. The cuts persisted even when the economy began to improve: a year ago half of the district's 650,000 students were still without a librarian or library aide.

Without library workers, state law prohibits students from browsing collections, pulling reference materials or checking out books. 

“We have been living without libraries and, no, we don’t want to because they are essential for academic achievement and learning for our students," said Mark Bobrosky, a librarian at Walter Reed Middle School.

School board member Monica Ratliff created a task force to recommend ways to expand libraries after KPCC reported that Lorne Street Elementary in Northridge had a library full of books collecting dust.

"This idea of equity — we are trying to make sure we don't have library deserts," Ratliff said at the board's curriculum, instruction and assessment committee meeting on Tuesday.

Even when the board committed funds for elementary school libraries, the district found it hard to fill openings. Library aides worked just three hours a day, five days a week.

Members of the task force suggested assigning library aides to two schools, doubling their hours and providing benefits.  Elementary school libraries began to quickly reopen. 

But while conditions have improved for elementary students, middle school libraries are still hard hit, with nearly 65 percent of their campus libraries shuttered.

Bobrosky said reopening the libraries is vital for L.A. Unified's success in implementing the Common Core state standards, which require research projects incorporating a variety of texts.

This content is from Southern California Public Radio. View the original story at SCPR.org.

Good morning and welcome. There has been unprecedented interest in recent years about whether marijuana or its constituent compounds should be used as medicine. Since 1996, voters in seven states have approved the medical use of marijuana.