It is shown how to reconstruct the stacking sequence from the pairwise correlation functions between layers in close-packed structures. First, of theoretical interest, the analytical formulation and solution of the problem are presented when the exact pairwise correlation counts are known. In the second part, the practical problem is approached. A simulated annealing procedure is developed to solve the problem using as initial guess approximate solutions from previous treatments. The robustness of the procedure is tested with synthetic data, followed by an experimental example. The developed approach performs robustly over different synthetic and experimental data, comparing favorably with the reported methods.

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.

Diffuse scattering is a rich source of information about disorder in crystalline materials, which can be modelled using atomistic techniques such as Monte Carlo and molecular dynamics simulations. Modern X-ray and neutron scattering instruments can rapidly measure large volumes of diffuse-scattering data. Unfortunately, current algorithms for atomistic diffuse-scattering calculations are too slow to model large data sets completely, because the fast Fourier transform (FFT) algorithm has long been considered unsuitable for such calculations [Butler & Welberry (1992). J. Appl. Cryst. 25, 391–399]. Here, a new approach is presented for ultrafast calculation of atomistic diffuse-scattering patterns. It is shown that the FFT can actually be used to perform such calculations rapidly, and that a fast method based on sampling theory can be used to reduce high-frequency noise in the calculations. These algorithms are benchmarked using realistic examples of compositional, magnetic and displacive disorder. They accelerate the calculations by a factor of at least 102, making refinement of atomistic models to large diffuse-scattering volumes practical.

Attempting to display the contents of an HDF5 file containing fixed-length UTF-8 encoded strings results in an unexpected error in MATLAB.

For example, the following code

  h5disp('myHDF5FileWithFixedLenUTF8Strings.h5')

returns this error:

Error using h5infoc
UTF-8 encoding is only supported for variable length strings.

Error in h5info (line 108)
hinfo = h5infoc(filename,location, useUtf8);

Error in h5disp>display_hdf5 (line 121)
hinfo = h5info(options.Filename,options.Location);

Error in h5disp (line 99)
display_hdf5(options);

In certain scenarios, a Subsystem Reference block changes its position. It can happen during: 

1. Loading of top model which contains the Subsystem Reference block 
2. Synchronization of Subsystem Reference block's contents
3. Converting a subsystem to Subsystem Reference block 

The crystal structure of tri­phenyl­methanol, C19H16O, has been redetermined using data collected at 295 and 153 K, and is compared to the model published by Ferguson et al. over 25 years ago [Ferguson et al. (1992). Acta Cryst. C48, 1272–1275] and that published by Serrano-González et al., using neutron and X-ray diffraction data [Serrano-González et al. (1999). J. Phys. Chem. B, 103, 6215–6223]. As predicted by these authors, the hy­droxy groups are involved in weak inter­molecular hydrogen bonds in the crystal, forming tetra­hedral tetra­­mers based on the two independent mol­ecules in the asymmetric unit, one of which is placed on the threefold symmetry axis of the Roverline{3} space group. However, the reliable determination of the hy­droxy H-atom positions is difficult to achieve, for two reasons. Firstly, a positional disorder affects the full asymmetric unit, which is split over two sets of positions, with occupancy factors of ca 0.74 and 0.26. Secondly, all hy­droxy H atoms are further disordered, either by symmetry, or through a positional disorder in the case of parts placed in general positions. We show that the correct description of the hydrogen-bonding scheme is possible only if diffraction data are collected at low temperature. The pro­chiral character of the hydrogen-bonded tetra­meric supra­molecular clusters leads to enanti­omorphic three-dimensional graphs in each tetra­mer. The crystal is thus a racemic mixture of supS and supR motifs, consistent with the centro­symmetric nature of the Roverline{3} space group.

The enanti­opure monopyrrolidine derivative (2S)-methyl (Z)-5-(2-tert-but­oxy-1-cyano-2-oxo­ethyl­idene)pyrrolidine-2-carboxyl­ate, C13H18N2O4, (1), represents a potential ligand and an attractive inter­mediate for the synthesis of chiral metal com­plexes. At the mol­ecular level, the com­pound features an intra­molecular N—H⋯O hydrogen bond; neighbouring mol­ecules inter­act via N—H⋯N contacts to form chains along [100]. Due to its elemental com­position, resonant scattering of the target com­pound is entirely insignificant for diffraction experiments with Mo Kα and small even for Cu Kα radiation. A preliminary study with the harder radiation type confirmed the chiral space group and the suitability of the single crystal chosen; as expected, the results concerning the absolute structure remained com­pletely inconclusive. A second data collection with the longer wavelength gave satisfactory quality indicators for the correct handedness of the mol­ecule, albeit with high standard uncertainties. The absolute configuration has been assessed independently: CD spectra for both enanti­omers of the target mol­ecule were calculated and the spectrum for the S-configured stereoisomer was in agreement with the experiment. The Cotton effect of (1) may be ascribed to π–π* transitions from HOMO to LUMO and from HOMO to LUMO+1. As both independent techniques agree with respect to the handedness of the target mol­ecule, the absolute structure may be assigned with a high degree of confidence.

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.

Brock Lesnar after losing his championship in the main event of Wrestlemania 31.; Credit: WWE

World Wrestling Entertainment held their annual Wrestlemania show last weekend in Northern California, the culmination of another year's worth of spectacle. According to the company, it was their highest grossing event of all-time, drawing $12.6 million, with an official attendance placing it fifth on their list of all-time crowds for the event. The show was headlined by former UFC Heavyweight Champion Brock Lesnar going up against up-and-coming star (and a relative of Dwayne "The Rock" Johnson) Roman Reigns.

WWE Network

It comes at a time when the company has embarked on a new way of making money: their over-the-top online programming provider, the WWE Network, where fans can pay $9.99 a month to see programming including what formerly used to cost $45 for most shows and $60 for Wrestlemania. They're one year in now on gambling that enough fans will want the Network that it will ultimately make them more money in the long-term, despite losing that pay-per-view revenue. Wall Street doesn't appear to be buying it — after announcing the day after Wrestlemania that they'd hit 1.3 million subscribers, WWE's stock took a significant loss.

"The point is not whether it's real or if it's staged. The point is, are you entertained by it, or not?" former WWE announcer Jim Ross told KPCC in an interview. WWE is looking for more fans to be entertained enough to plunk down $9.99 for all the pro wrestling content they want.

NXT

They're also in a transitional period with their audiences. They've launched a new show that's only on the Network called "NXT," turning their minor league into a program targeting hardcore pro wrestling fans with a different style of show than the more family-targeted "Raw" and "Smackdown." It's also where they groom potential future stars, many of whom seem to break the mold of some of the traditional stars on WWE's main roster.

They're signing up talent that's been getting buzz on the independent circuits, trying to create their own underground movement that hopefully spells money, and taking the NXT brand on tour for the first time. On the Raw after Wrestlemania, several NXT stars made their debut on the main roster. That follows a sell-out crowd (albeit at a smaller 5,000 seat venue) on the Friday night before Wrestlemania for a non-televised NXT show.

Give Divas a chance

WWE also faces cultural forces pushing them in new directions, including a difference in how society deals with gender. When WWE executive Stephanie McMahon, daughter of the famed Vince McMahon, tweeted in support of Patricia Arquette's speech calling for greater equality for women at the Academy Awards, one of their own wrestlers, AJ Lee, responded by publicly calling Stephanie McMahon out on Twitter for not promoting the women in her own company equally and paying them less than the male stars.

AJ tweet 1

AJ tweet 2

Of course, the women in the company aren't given the same prominence as the men in part because it's felt that they won't make the company as much money. Still, it forced WWE's hand and Stephanie McMahon and the company as a whole publicly embraced the idea of giving the women (who WWE brands as "divas") a chance with the Give Divas A Chance movement (and accompanying trending hashtag).

What's next

The women have been promoted nearly equal to the men in that underground NXT league, but only time will tell if it continues to trickle upward. Wrestlemania didn't seem to show huge promise of that happening, with the one women's match of the show only getting a few minutes in the ring. However, the show also included a high-profile storyline with UFC female fighter and champion Ronda Rousey alongside the Rock, going up against Stephanie McMahon and Triple H, so there appears to be the room for women in prominent positions when they have the right storyline.

Whether WWE is able to wade through these forces of change to make more money — and perhaps regain some of the cultural currency that they've lost since becoming a monopoly and purchasing their top competition in 2001 — remains to be seen. They've stayed relatively steady despite a challenge from UFC, which many see as being what pro wrestling would be like if WWE didn't present fictional  They'll have to hope that giving new stars, including "divas," a chance will take them to another level.

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

The Debye scattering equation (DSE) is generalized and augmented in order to account for moderate texture effects, yielding the differential cross section as a function of atomic coordinates and texture coefficients subject to symmetry constraints. Implications for the evaluation of the pair distribution function (PDF) as a direct transform of powder diffraction data from textured samples are also discussed.

Celo, a competing project to...

The US Federal Reserve has created a new group to advise on its planned faster payments service, the FedNow...

Norbert Volkmar
Apr 24, 2020; 133:jcs243519-jcs243519
REVIEW

Cancer-causing chemicals that occur naturally in foods are far more numerous in the human diet than synthetic carcinogens, yet both types are consumed at levels so low that they currently appear to pose little threat to human health, a committee of the National Research Council said in a report released today.

To ensure that minority students who are poorly prepared for school are not assigned to special education for that reason, educators should be required to first provide them with high-quality instruction and social support in a general education classroom before making a determination that special education is needed.

Use of protective face coverings will be one of many strategies used to slow or prevent transmission of the flu virus in the event of a pandemic, even though scientific evidence about the effectiveness of inexpensive, disposable medical masks and respirators against influenza is limited.

Long-term population trends for some North American pollinators -- bees, birds, bats, and other animals and insects that spread pollen so plant fertilization can occur -- are demonstrably downward, says a new report from the National Research Council.

The U.S. National Academy of Engineering (NAE) today announced the grand challenges for engineering in the 21st century. A diverse committee of experts from around the world, convened at the request of the U.S. National Science Foundation, revealed 14 challenges that, if met, would improve how we live.

Good morning. I am Dr. Alice Gast and I am here today with Dr. David Relman as the chair and vice chair of the Committee on the Review of the Scientific Approaches Used During the FBI’s Investigation of the 2001 Bacillus anthracis Mailings.

A growing amount of scientific evidence indicates that how much weight women gain during pregnancy and their starting weight at conception can affect their health and that of their babies, says a new report from the Institute of Medicine and the National Research Council.

A new report from the National Research Council lays out options NASA could follow to detect more near-Earth objects (NEOs) – asteroids and comets that could pose a hazard if they cross Earths orbit.

Hydraulic fracturing has a low risk for inducing earthquakes that can be felt by people, but underground injection of wastewater produced by hydraulic fracturing and other energy technologies has a higher risk of causing such earthquakes, says a new report from the National Research Council.

A review of the available evidence underscores the safety of the federal childhood immunization schedule, says a new report from the Institute of Medicine.

The National Academy of Engineering (NAE) has elected 67 new members and 11 foreign associates, announced NAE President C.D. (Dan) Mote Jr. today. This brings the total U.S. membership to 2,250 and the number of foreign associates to 214.

Young adults ages 18-26 should be viewed as a separate subpopulation in policy and research, because they are in a critical period of development when successes or failures could strongly affect the trajectories of their lives, says a new report from the Institute of Medicine and National Research Council.

Cardiac arrest strikes almost 600,000 people each year, killing the vast majority of those individuals, says a new report from the Institute of Medicine. Every year in the U.S., approximately 395,000 cases of cardiac arrest occur outside of a hospital setting, in which less than 6 percent survive.

We thank the organizers of our International Summit on Human Gene Editing for their thoughtful concluding statement and welcome their call for us to continue to lead a global discussion on issues related to human gene editing.

The latest and final in a series of congressionally mandated biennial reviews of the evidence of health problems that may be linked to exposure to Agent Orange and other herbicides used during the Vietnam War changed the categorization of health outcomes for bladder cancer, hypothyroidism, and spina bifida and clarified the breadth of the previous finding for Parkinson’s disease.

Today the science academies of the G7 countries and seven additional academies issued three joint statements to their respective governments to inform discussions during the G7 summit to be held in May in Japan, as well as ongoing policymaking.

Over the last 25 years, deep-water oil and gas production in the Gulf of Mexico has increased significantly.

The 2011 Fukushima Daiichi nuclear accident should serve as a wake-up call to nuclear plant operators and regulators on the critical importance of measuring, maintaining, and restoring cooling in spent fuel pools during severe accidents and terrorist attacks, says a new report from the National Academies of Sciences, Engineering, and Medicine.

Hearing loss is a significant public health concern, and efforts should be made to provide adults with easier access to and more affordable options for hearing health care, especially for those in underserved and vulnerable populations, says a new report from the National Academies of Sciences, Engineering, and Medicine.

To improve and ensure the efficacy of restoration efforts in the Gulf of Mexico following Deepwater Horizon – the largest oil spill in U.S. history – a new report from the National Academies of Sciences, Engineering, and Medicine recommends a set of best practices for monitoring and evaluating ecological restoration activities.