New images from NASA's Lunar Reconnaissance Orbiter (LRO) spacecraft show the moon's crust is being stretched, forming minute valleys in a few small areas on the lunar surface.

The post Photos reveal recent activity in moon’s crust appeared first on Smithsonian Insider.

According to the weekly report of the Smithsonian’s Global Volcanism Program, gas-and-ash plumes rose nearly one mile above the crater of Mexico’s Popocatépetl volcano from […]

The post Mexico’s Popocatepetl volcano active again appeared first on Smithsonian Insider.

Even tiny crustaceans scuttling across the deepest, darkest depths of the ocean floor will feel the effects of climate change, according to a new study […]

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Images obtained by NASA’s MErcury Surface, Space ENvironment, GEochemistry and Ranging (MESSENGER) spacecraft during the low-altitude orbital phase of the mission have revealed previously undetected […]

The post Mercury Joins Earth As Tectonically Active Planet appeared first on Smithsonian Insider.

To get a better idea of just what is going on with the current volcanic eruption of Kilauea on the island of Hawaii, take a […]

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Seven corrections are made and several supplementary equations are added to the article by Yoshimura [Acta Cryst. (2015), A71, 368–381].

Structural investigations of amorphous and nanocrystalline phases forming in solution are historically challenging. Few methods are capable of in situ atomic structural analysis and rigorous control of the system. A mixed-flow reactor (MFR) is used for total X-ray scattering experiments to examine the short- and long-range structure of phases in situ with pair distribution function (PDF) analysis. The adaptable experimental setup enables data collection for a range of different system chemistries, initial supersaturations and residence times. The age of the sample during analysis is controlled by adjusting the flow rate. Faster rates allow for younger samples to be examined, but if flow is too fast not enough data are acquired to average out excess signal noise. Slower flow rates form older samples, but at very slow speeds particles settle and block flow, clogging the system. Proper background collection and subtraction is critical for data optimization. Overall, this MFR method is an ideal scheme for analyzing the in situ structures of phases that form during crystal growth in solution. As a proof of concept, high-resolution total X-ray scattering data of amorphous and crystalline calcium phosphates and amorphous calcium carbonate were collected for PDF analysis.

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.

Relativistic electron diffraction depends on linear and quadratic terms in the electric potential, the latter being neglected in the frequently used relativistically corrected Schrödinger equation. The quadratic electric potential term modifies atomic scattering amplitudes in particular for large-angle scattering and backscattering. The respective correction increases with increasing scattering angle, increasing atomic number and increasing kinetic energy. Conventional tabulations for electron scattering and its large-angle extrapolations can be amended in closed form by a universal correction based on the screened Coulomb potential squared.

The use of strongly bent crystals in spectrometers for pulses of a hard X-ray free-electron laser is explored theoretically. Diffraction is calculated in both dynamical and kinematical theories. It is shown that diffraction can be treated kinematically when the bending radius is small compared with the critical radius given by the ratio of the Bragg-case extinction length for the actual reflection to the Darwin width of this reflection. As a result, the spectral resolution is limited by the crystal thickness, rather than the extinction length, and can become better than the resolution of a planar dynamically diffracting crystal. As an example, it is demonstrated that spectra of the 12 keV pulses can be resolved in the 440 reflection from a 20 µm-thick diamond crystal bent to a radius of 10 cm.

A crystallographic indexing algorithm, pinkIndexer, is presented for the analysis of snapshot diffraction patterns. It can be used in a variety of contexts including measurements made with a monochromatic radiation source, a polychromatic source or with radiation of very short wavelength. As such, the algorithm is particularly suited to automated data processing for two emerging measurement techniques for macromolecular structure determination: serial pink-beam X-ray crystallography and serial electron crystallography, which until now lacked reliable programs for analyzing many individual diffraction patterns from crystals of uncorrelated orientation. The algorithm requires approximate knowledge of the unit-cell parameters of the crystal, but not the wavelengths associated with each Bragg spot. The use of pinkIndexer is demonstrated by obtaining 1005 lattices from a published pink-beam serial crystallography data set that had previously yielded 140 indexed lattices. Additionally, in tests on experimental serial crystallography diffraction data recorded with quasi-monochromatic X-rays and with electrons the algorithm indexed more patterns than other programs tested.

Crystal structure identification of thin organic films entails a number of technical and methodological challenges. In particular, if molecular crystals are epitaxially grown on single-crystalline substrates a complex scenario of multiple preferred orientations of the adsorbate, several symmetry-related in-plane alignments and the occurrence of unknown polymorphs is frequently observed. In theory, the parameters of the reduced unit cell and its orientation can simply be obtained from the matrix of three linearly independent reciprocal-space vectors. However, if the sample exhibits unit cells in various orientations and/or with different lattice parameters, it is necessary to assign all experimentally obtained reflections to their associated individual origin. In the present work, an effective algorithm is described to accomplish this task in order to determine the unit-cell parameters of complex systems comprising different orientations and polymorphs. This method is applied to a polycrystalline thin film of the conjugated organic material 6,13-pentacene­quinone (PQ) epitaxially grown on an Ag(111) surface. All reciprocal vectors can be allocated to unit cells of the same lattice constants but grown in various orientations [sixfold rotational symmetry for the contact planes (102) and (102)]. The as-determined unit cell is identical to that reported in a previous study determined for a fibre-textured PQ film. Preliminary results further indicate that the algorithm is especially effective in analysing epitaxially grown crystallites not only for various orientations, but also if different polymorphs are present in the film.

Recent developments of two-color operation modes at X-ray free-electron laser facilities provide new research opportunities, such as X-ray pump/X-ray probe experiments and multiple-wavelength anomalous dispersion phasing methods. However, most existing indexing methods were developed for indexing diffraction data from monochromatic X-ray beams. Here, a new algorithm is presented for indexing two-color diffraction data, as an extension of the sparse-pattern indexing algorithm SPIND, which has been demonstrated to be capable of indexing diffraction patterns with as few as five peaks. The principle and implementation of the two-color indexing method, SPIND-TC, are reported in this paper. The algorithm was tested on both simulated and experimental data of protein crystals. The results show that the diffraction data can be accurately indexed in both cases. Source codes are publicly available at https://github.com/lixx11/SPIND-TC.

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The HSBC Climate Partnership (HCP) is a five-year partnership (2007-2011) between HSBC, The Smithsonian, The Climate Group, Earthwatch Institute and WWF to inspire action on climate change.
Working with these partners and engaging its employees around the world, HSBC hopes to tackle climate change impacts for people, forests, water, and cities. The HCP research of the Smithsonian's Center for Tropical Forest Science (CTFS) focuses on:
• Understanding the role of forests in the global carbon cycle
• Comparing temperate and tropical forests by establishing new plots in the temperate zone
• Quantifying the environmental services provided by tropical forests

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It takes a Tlingit artist up to 2,000 hours, or 83 days, to weave just one ceremonial robe. Not surprisingly, this art form is practiced by a dedicated few including Tlingit artists Teri Rofkar and Shelly Laws of Alaska. In their presentation for the Smithsonian Spotlight series hosted by the Arctic Studies Center at the Anchorage Museum, Rofkar and Laws discuss the methods and cultural significance of robes, spruce root baskets and more.
For more information, go to http://www.mnh.si.edu/arctic/html/alaska.htm

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In an excerpt from “60 Minutes” on Sunday, Nov. 1 2016, Scott Pelley follows National Museum of African American History and Culture director Lonnie Burch […]

The post Slave Ship Artifacts Recovered appeared first on Smithsonian Insider.

Meet Amy Homma, the Director of Digital Learning at Art Lab+. Learn how Smithsonian’s Hirshhorn Museum and Sculpture Garden has created a dynamic program to […]

The post An Active Environment With Smithsonian Educator: Amy Homma appeared first on Smithsonian Insider.

Watch this video before the solar eclipse on August 21, 2017!

The post 7 Facts About Solar Eclipses appeared first on Smithsonian Insider.

Sign ups for the Affordable Care Act start in a week, and the program is leading to changes in the way employers handle health coverage.

Steve Julian: Business analyst Mark Lacter, what's the most noticeable adjustment?

Mark Lacter: Steve, once you get beyond the squabbling over efforts to defund the new law, what's happening is quite remarkable: businesses are finding new ways to administer and pay for coverage - and some would say it's long overdue.  One interesting example: the grocery chain Trader Joe's, which is based in Monrovia, employs over 20,000 people, and shells out millions of dollars a year in helping provide its people with health insurance.  Well, Trader Joe's has decided to end coverage for part-timers working fewer than 30 hours a week - under the new law businesses are not obligated to provide benefits to employees who work less than that amount.  However, the company is giving those people $500 to go towards the purchase of premiums at the new public exchanges.  And that, along with the tax credits available, could make the new arrangement cost about the same or even cheaper than the current health care package.

Julian: How did TJ's explain this to its employees?

Lacter: The company cited the example of an employee with one child who makes $18 an hour and works 25 hours a week.  Under the old system, she pays $166 a month for coverage; under the new system, she can get a nearly identical plan for $70 a month.  Now, there are cases in which workers will end up paying more - usually it involves having a family member who makes more money, but who doesn't have access to coverage (good example would be an independent contractor or freelancer).  By the way, other companies - including the drug store chain Walgreen's - are also moving part-timers to the public market, and offering some sort of a subsidy.

Julian: I imagine not all companies are being as conscientious...

Lacter: No.  We've seen a number of corporations cut worker hours and not offer a supplemental payment.  Steve, it's worth remembering that administering health insurance is something that businesses fell into quite by accident 60 years or so ago - premiums cost next to nothing at the time, and it was seen as way of attracting workers without having to jack up wages.  The arrangement became more attractive over the years because of certain tax benefits.  But, it's far from ideal - workers move from job to job more often than they used to, and not all businesses are capable of handling the extra costs, especially small businesses.

Julian: Doesn't L.A. have a higher percentage of uninsured than elsewhere?

Lacter: Considerably higher - the Census Bureau show that 21 percent did not have coverage in 2012, which is higher than the overall national number.  Now, there are a bunch of reasons for this: L.A. has a large percentage of households that simply can't afford health insurance or don't have access to government programs, among them undocumented immigrants.  You also have big numbers of people who are self-employed and don't get covered - we're talking about freelancers or consultants of some sort.

Julian: …Or, they work for small businesses whose owners either can't afford, or don't want to provide coverage…

Lacter: That's right - the new law only requires businesses with more than 50 full-time workers to offer health insurance, and a lot of small businesses don't meet that threshold.  The Census Bureau says that in the L.A. area, one in four people with jobs do not have health insurance - and, by the way, there's been a drop-off both in the percentage of businesses in California that offer coverage.

Julian: Sounds dire.  Who picks up the cost?

Lacter: Well, we all do in one way or another - and that, of course, is the problem.  What the Affordable Care Act offers is a start in getting some of the uninsured onto the rolls.  Clearly, it's an imperfect solution that will require all sorts of adjustments, and even though everyone and their uncle seems to have formed a definitive opinion about the new law, it's going to be years before there's any real sense of how it's going.  And, let's remember, signing up for these programs is not some political act.  It's just a way for people to get health insurance for themselves and their families.

Mark Lacter writes for Los Angeles Magazine and pens the business blog at LA Observed.com.

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

The partial federal government shutdown is one week old, but economists are still saying that its impact in Southern California and elsewhere will be limited.

Susanne Whatley: Business analyst Mark Lacter, why is that?

Mark Lacter: If you look back on the history of these things, Susanne, you see that the disputes are resolved before too much damage gets done.  As for Southern California, I notice that KPCC's Alice Walton was asking around over the weekend about the shutdown, and most folks gave it a shrug.  The regional economy is just too diversified - and not especially tied to federal employment.  You have about 46,000 federal workers employed in L.A. County in one capacity or another - that's out of a workforce of nearly 5 million.  And, now it appears as if the federal employees who have been furloughed are going to receive their back wages whenever the shutdown finally ends.

Whatley: That still might make things dicey when it comes time to pay the monthly mortgage...

Lacter: ...but at least money will be available before most folks run into serious liquidity issues.  That's what the shutdown really comes down to - inconvenience rather than dislocation.  And, you see this with the various government services affected: the E-Verify website is down - that lets business owners know whether the people they're wanting to hire can work legally in the U.S., which obviously is important.  The Small Business Administration has stopped processing loan applications, and the Federal Housing Administration is reporting delays in its loan processing, which could mean a home buyer might not complete his or her paperwork all that quickly.

Whatley: But, what if this were to go on for months?

Lacter: Well, then it would create problems, but nobody really thinks that's going to happen.  The real issue, not just nationally and regionally - but globally - is the refusal by Congress to raise the debt ceiling.  The deadline is a week from Thursday, and - of course - there's been all sorts of debate about what this would mean for the economy.

Whatley: All right, so what would this mean for the economy?

Lacter: Well, no one knows exactly.  But, then again, no one knows exactly what would happen if you fell out of a airplane without a parachute.  I just wouldn't want to test it out.  And, of course, let's keep in mind that these are manufactured crises - not reflective of anything that's going on with the real economy.  It's certainly not reflective of anything that's going on in L.A., which saw a big jump in payroll jobs for 2012 - actually it was the sharpest increase since 2005, and nearly double the national rate (that's despite an unemployment rate that remains very high in certain parts of Los Angeles).

Whatley: What about some of the big locally based companies?

Lacter: Well, if your company is publicly traded, there's a good chance your shares took a dip these past few days.  Going back to September 18, the Dow has lost almost 700 points, which - percentage-wise - is not very much, but it is reflective of how uneasy Wall Street has become.  Public companies based in the L.A. area are taking it on the chin - Disney, Amgen, Mattel, DirecTV - their stock prices are all down going back to the middle of September.

Whatley: Even so, hasn't this been a good year for the stock market?

Lacter: It has - those local companies are up anywhere from 13 percent 30 percent year to date, and the Dow is up 14 percent year to date.  Of course, the stock price of a company doesn't always match the amount of money it makes, and this year, even before worries about the debt ceiling, the numbers haven't been as good as they should be at this stage of a recovery.  And, that's why there's particular concern about next week.  You do have to wonder whether a default could have ripple effects involving trade, consumer spending, the dollar - who knows what?  Now, it's still a pretty good bet that saner heads will prevail, although there are no guarantees - and again, if worse came to worse, do you really want to be jumping out of that plane?  Guess we'll find out.

Mark Lacter writes for Los Angeles Magazine and pens the business blog at LA Observed.com.

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

The state's online registration for Covered California has been up for a couple of weeks, and reaction has been mixed.

Steve Julian: Business analyst, Mark Lacter, what's your take on how well Californians are getting into the Affordable Care Act?

Mark Lacter: It's hard to get a good read, Steve, because it's hard to measure the success of what is really a new marketplace.  If you're basing it on the number of unique visitors coming to the Covered California website, well, then the program clearly has attracted lots of interest - they had almost a million visitors during the first week of eligibility.  But, maybe a better measure would be the number of people whose applications actually have been received by the insurance companies that are going to handle the claims.  If that's your measuring stick, then the numbers have been far smaller so far.  Now, it's worth pointing out that California - and particularly L.A. County - have a higher percentage of households without insurance than other parts of the nation, and so you'd expect there to be lots of interest.

Julian: So the question, then, is how many folks turn into actual policyholders paying actual premiums each month.

Lacter: The truth is nobody knows, which is why state officials want to sign up as many people as possible in the early going when the program is getting so much attention.  This is especially true for younger and healthier people who are needed to help offset the cost of caring for older and sicker people.

Julian: And, that's also why any computer glitch can be such a headache...

Lacter: That's right.  Covered California did run into problems in the early going, but everybody agrees that things are going much better than the federal website, which is the default site used by folks in states that don't have their own program to oversee the health care laws.  That federal site has been an utter disaster.  So, by comparison, California is ahead of the game.

Julian: It's a work in progress, even here.

Lacter: Very much so.  The California website still doesn't have a way for enrollees to find out which doctors and hospitals are included in each health plan.  And, that's a big deal because  insurance companies are limiting the options available as a way of keeping premiums low.  So, it's possible that the doctor you had been using for your individual insurance plan will not be on the list of doctors that can be used for one of the cheaper plans.  Of course, for someone who doesn't have any health coverage, none of that is likely to matter.

Julian: And then, there's the continued threat of a U.S. default...

Lacter: You know, Steve, this is like watching the beginning of a bad traffic accident in slow motion - and we're all pretty helpless to do anything about it.  And, so are the financial markets, which are moving back and forth not based on what's going on with the economy or with any industry, but on the latest press conference out of Washington.  One thing we do know is that if the nation does go into quote-unquote default - and we're not even sure what that might mean - but if Wall Street and somehow declares this a major crisis, it's going to be bad.

Julian: Who gets hit?

Lacter: It'll impact anyone who has a retirement account, any business wanting to borrow money, and potentially it's going to impact the budgeting of the state.  You know, one of the things we were reminded of during the Great Recession was how reliant California has been on higher-income individuals who make a lot of their money through the stock market and other investments.  So, when those folks do well - as they have been over the last year - the state coffers will do well.  And when they don't, as was the case in 2008 and 2009, the state takes a huge hit because there's not enough tax dollars coming in.  Gov. Brown and others have tried to lessen the reliance on those top tiers - so far without success.

Julian: And the state's budget situation is so much better than it was a year or two ago.

Lacter: That's the real pity.  And, even if the House and Senate reach a temporary agreement on the debt ceiling, it's just a matter of weeks or months before another deadline crops up - and more uncertainty for the financial markets.  I guess Chick Hearn would have called this nervous time.

Mark Lacter writes for Los Angeles Magazine and pens the business blog at LA Observed.com.

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

What they observed was unique among all bird species: successful male caribs maintained and defended territories with nectar supplies that were two to five times greater than their daily needs and also isolated part of their crop for the exclusive feeding rights of visiting females.

The post A well-defended territory is what some female hummingbirds find most attractive in a mate appeared first on Smithsonian Insider.

New results from a massive study at the Smithsonian Tropical Research Institute show that interactions among community members play an important role in determining which organisms thrive.

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When you’re caught under the mistletoe, the tradition is to kiss the person next to you. But this holiday season you may want to wow them first with some cool mistletoe facts from Smithsonian botanist Sylvia Orli.

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Katie Cramer is a MarineGEO Post-Doctoral Fellow and travels to Smithsonian Tropical Research Institute in Panama throughout the year to conduct research. Her recent paper […]

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Scientific inspiration springs from many sources. In the case of Smithsonian botanist David Kenfack, ant bites were the inspiration for a recent paper he co-authored […]

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A tiny invasive insect from Asia might have an effect on Chesapeake Bay waters. The emerald ash borer is killing millions of ash trees in […]

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The new copper(II) complex [CuLCl2]2, where L is a product of Schiff base condensation between methyl­amine and 2-pyridine­carbaldehyde, is built of discrete centrosymmetric dimers.

This work presents a technique for extracting the detailed shape of peaks with extended, overlapping tails in an X-ray powder diffraction pattern. The application discussed here concerns crystallite size broadening, though the technique can be applied to spectra of any origin and without regard to how the profiles are to be subsequently analyzed. Historically, the extraction of profile shapes has been difficult due to the complexity of determining the background under the peak, resulting in an offset of the low-frequency components of the Fourier transform of the peak known as the `hook' problem. The use of a carefully considered statistical weighting function in a non-linear least-squares fit, followed by summing the residuals from such a fit with the fit itself, allows one to extract the full shape of an isolated peak, without contributions from either the background or adjacent peaks. The extracted shape, consisting of the fit function recombined with the residuals, is not dependent on any specific shape model. The application of this to analysis of microstructure is performed independently of global parametric models, which would reduce the number of refined parameters; therefore the technique requires high-quality data to produce results of interest. The effectiveness of the technique is demonstrated by extraction of Fourier transforms of peaks from two sets of size-broadened materials with two differing pieces of equipment.

The methods for X-ray crystal orientation are rapidly evolving towards versatility, fewer goniometry measurements, automation, high accuracy and precision. One method that attracts a lot of attention is energy-dispersive X-ray diffraction (EDXRD) which is based on detecting reflections from crystallographic planes in a crystal at fixed angles of a parallel polychromatic X-ray incident beam. In theory, an EDXRD peak can move in a diffraction pattern as a function of a crystallographic plane d-spacing and its orientation relative to a fixed direction in space can change also. This is equivalent to the possibility of measuring the orientation of single crystals. The article provides a modeling for the EDXRD method whose main feature is the nonmoving crystal in the sense of traditional goniometry where the angle measurements of diffracting planes are a must. The article defines the equation of orientation for the method and shows the derivation in great detail. It is shown that the exact solutions of the equations can be obtained using the generalized reduced gradient method, a mathematical subroutine that is implemented in Excel software. The significance and scientific impact of the work are discussed along with the validated tested results.

A new aspherical scattering factor formalism has been implemented in the crystallographic least-squares refinement program SHELXL. The formalism relies on Gaussian functions and can optionally complement the independent atom model to take into account the deformation of electron-density distribution due to chemical bonding and lone pairs. Asphericity contributions were derived from the electron density obtained from quantum-chemical density functional theory computations of suitable model compounds that contain particular chemical environments, as defined by the invariom formalism. Thanks to a new algorithm, invariom assignment for refinement in SHELXL is automated. A suitable parameterization for each chemical environment within the new model was achieved by metaheuristics. Figures of merit, precision and accuracy of crystallographic least-squares refinements improve significantly upon using the new model.

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.

The new copper(II) complex, namely, di-μ-chlorido-bis{chlorido[methyl(pyridin-2-ylmethylidene)amine-κ2N,N']copper(II)}, [Cu2Cl4(C7H8N2)2], (I), with the ligand 2-pyridylmethyl-N-methylimine (L, a product of Schiff base condensation between methylamine and 2-pyridinecarbaldehyde) is built of discrete centrosymmetric dimers. The coordination about the CuII ion can be described as distorted square pyramidal. The base of the pyramid consists of two nitrogen atoms from the bidentate chelate L [Cu—N = 2.0241 (9), 2.0374 (8) Å] and two chlorine atoms [Cu—Cl = 2.2500 (3), 2.2835 (3) Å]. The apical position is occupied by another Cl atom with the apical bond being significantly elongated at 2.6112 (3) Å. The trans angles of the base are 155.16 (3) and 173.79 (2)°. The Cu...Cu separation in the dimer is 3.4346 (3) Å. In the crystal structure, the loosely packed dimers are arranged in stacks propagating along the a axis. The X-band polycrystalline 77 K EPR spectrum of (I) demonstrates a typical axial pattern characteristic of mononuclear CuII complexes. Compound (I) is redox active and shows a cyclic voltammetric response with E1/2 = −0.037 V versus silver–silver chloride electrode (SSCE) assignable to the reduction peak of CuII/CuI in methanol as solvent.

An error in an equation in the paper by Song et al. [Acta Cryst. (2019), C75, 1353–1358] is corrected.

An efficient synthesis of 1-aryl­isochromeno[3,4-d][1,2,3]triazol-5(1H)-ones, involving the diazo­tization of 3-amino-4-aryl­amino-1H-isochromen-1-ones in weakly acidic solution, has been developed and the spectroscopic characterization and crystal structures of four examples are reported. The mol­ecules of 1-phenyl­isochromeno[3,4-d][1,2,3]triazol-5(1H)-one, C15H9N3O2, (I), are linked into sheets by a combination of C—H⋯N and C—H⋯O hydrogen bonds, while the structures of 1-(2-methyl­phen­yl)isochromeno[3,4-d][1,2,3]triazol-5(1H)-one, C16H11N3O2, (II), and 1-(3-chloro­phen­yl)isochromeno[3,4-d][1,2,3]triazol-5(1H)-one, C15H8ClN3O2, (III), each contain just one hydrogen bond which links the mol­ecules into simple chains, which are further linked into sheets by π-stacking inter­actions in (II) but not in (III). In the structure of 1-(4-chloro­phen­yl)isochromeno[3,4-d][1,2,3]triazol-5(1H)-one, (IV), isomeric with (III), a combination of C—H⋯O and C—H⋯π(arene) hydrogen bonds links the mol­ecules into sheets. When com­pound (II) was exposed to a strong acid in methanol, qu­anti­tative conversion occurred to give the ring-opened transesterification product methyl 2-[4-hy­droxy-1-(2-methyl­phen­yl)-1H-1,2,3-triazol-5-yl]benzoate, C17H15N3O3, (V), where the mol­ecules are linked by paired O—H⋯O hydrogen bonds to form centrosymmetric dimers.

An operationally simple and time-efficient approach has been developed for the synthesis of racemic N-substituted 3-(2-aryl-2-oxoeth­yl)-3-hy­droxy­indolin-2-ones by a piperidine-catalysed aldol reaction between aryl methyl ketones and N-alkyl­isatins. These aldol products were used successfully as strategic inter­mediates for the preparation of N-substituted (E)-3-(2-hetaryl-2-oxo­ethyl­idene)indolin-2-ones by a stereoselective dehydration reaction under acidic conditions. The products have all been fully characterized by 1H and 13C NMR spectroscopy, by mass spectrometry and, for a representative selection, by crystal structure analysis. In each of (RS)-1-benzyl-3-hy­droxy-3-[2-(4-meth­oxy­phen­yl)-2-oxoeth­yl]indolin-2-one, C24H21NO4, (Ic), and (RS)-1-benzyl-3-{2-[4-(di­methyl­amino)­phen­yl]-2-oxoeth­yl}-3-hy­droxy­indolin-2-one, C25H24N2O3, (Id), inversion-related pairs of mol­ecules are linked by O—H⋯O hydrogen bonds to form R22(10) rings, which are further linked into chains of rings by a combination of C—H⋯O and C—H⋯π(arene) hydrogen bonds in (Ic) and by C—H⋯π(arene) hydrogen bonds in (Id). The mol­ecules of (RS)-1-benzyl-3-hy­droxy-3-[2-oxo-2-(pyridin-4-yl)eth­yl]indolin-2-one, C22H18N2O3, (Ie), are linked into a three-dimensional framework structure by a combination of O—H⋯N, C—H⋯O and C—H⋯π(arene) hydrogen bonds. (RS)-3-[2-(Benzo[d][1,3]dioxol-5-yl)-2-oxoeth­yl]-1-benzyl-3-hy­droxy­indolin-2-one, C24H19NO5, (If), crystallizes with Z' = 2 in the space group Poverline{1} and the mol­ecules are linked into com­plex sheets by a combination of O—H⋯O, C—H⋯O and C—H⋯π(arene) hydro­gen bonds. In each of (E)-1-benzyl-3-[2-(4-fluoro­phen­yl)-2-oxo­ethyl­idene]indolin-2-one, C23H16FNO2, (IIa), and (E)-1-benzyl-3-[2-oxo-2-(thiophen-2-yl)ethylidene]indolin-2-one, C21H15NO2S, (IIg), the mol­ecules are linked into simple chains by a single C—H⋯O hydrogen bond, while those of (E)-1-benzyl-3-[2-oxo-2-(pyridin-4-yl)ethyl­idene]indolin-2-one, C22H16N2O2, (IIe), are linked by three C—H⋯O hydrogen bonds to form sheets which are further linked into a three-dimensional structure by C—H⋯π(arene) hydrogen bonds. There are no hydrogen bonds in the structures of either (E)-1-benzyl-3-[2-(4-meth­oxy­phen­yl)-2-oxo­ethyl­idene]indolin-2-one, C24H19NO3, (IIc), or (E)-1-benzyl-5-chloro-3-[2-(4-chloro­phen­yl)-2-oxo­ethyl­idene]indolin-2-one, C23H15Cl2NO2, (IIh), but the mol­ecules of (IIh) are linked into chains of π-stacked dimers by a combination of C—Cl⋯π(arene) and aromatic π–π stacking inter­actions.

A large The Actor statue is placed on stage during 21st Annual SAG Awards Behind The Scenes At The Shrine Auditorium Jan. 23, 2015 in Los Angeles.; Credit: Kevork Djansezian/Getty Images

Click here for KPCC's Awards Tracker

This Sunday's Screen Actors Guild Awards aren't as high profile as the Academy Awards, or even the Golden Globes, but they serve as one of the best predictors of who's going to take home a gold statue come Oscar night. Here's why.

Who votes for the SAG Awards?

SAG Award nominees are chosen by a committee of about 2,100 of the guild's members, according to awards news site Gold Derby. Then, all of the 111,228 members of the Guild have the chance to vote for their picks.

Meanwhile, the acting nominees for the Academy Awards are chosen by the 1,100 members in the Academy's actors branch, before being voted on by the Academy's full 5,700 members. Those actors are all part of SAG, so you're likely to see a strong correlation most years between the awards, particularly in the acting category.

How often do the SAG Awards predict the Oscar winners?

The SAG Awards have proven to be the best Oscar predictor in the acting category of any other major awards season prize since they began in 1995, both in nominations and winners. Of the 20 nominations and four winners from each shows, the overlap between the SAG Awards (aka "the Actors") and the Academy Awards in the last few years:

• 2009: 18 nominations; 3 winners
• 2010: 19 nominations; all 4 winners
• 2011: 17 nominations; all 4 winners
• 2012: 16 nominations; 3 winners
• 2013: 15 nominations; 3 winners
• 2014: 14 nominations; all 4 winners

This year, 17 nominees crossed over between the awards shows, with the Oscars matching up on all five nominations for best supporting actor and four of the five nominations in the other three acting categories.

Where have the SAG Awards differed from the Oscars?

SAG voters have lined up with the Academy on Best Actor 16 out of 20 times. The last time they differed from the Oscars was 2003, when Johnny Depp won at the SAG Awards for "Pirates of the Caribbean: Curse of the Black Pearl" before Sean Penn took the statue home at the Oscars for "Mystic River."

For Best Actress, SAG last split from Oscar in 2011, going with Viola Davis for "The Help" over eventual Oscar winner Meryl Streep for "The Iron Lady." They've matched up 14 out of 20 years.

In the supporting categories, the SAG Awards haven't fared as well. They went 12 for 20 in Best Supporting Actor, and 13 for 20 in Best Supporting Actress. That one also has an asterisk — one of those was a tie, so if you don't count that one, they're also only 12 for 20.

What does this all mean for the Oscars?

The SAG Awards remain the ones to watch when it comes to the acting awards — though their Best Ensemble category, the SAG Awards version of Best Picture, doesn't have a particularly strong correlation to the Oscars Best Picture winner. (For that, you'll want to watch for the Producers Guild Awards.)

We're tracking awards season and what experts are predicting; see KPCC's Awards Tracker below or click here to see the full page. You can watch the Screen Actors Guild Awards this Sunday at 5 p.m. Pacific, 8 p.m. Eastern on both TBS and TNT.

Disclosure: Mike Roe, along with other members of KPCC's staff, are members of the Screen Actors Guild as part of their employment with KPCC.

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

Features of azimuthal plots for RHEED and its new counterpart, RHEPD, are discussed. The plots, for both electrons and positrons, are determined using dynamical diffraction theory.