Over the last decade, the development of time-resolved serial crystallography (TR-SX) at X-ray free-electron lasers (XFELs) and synchrotrons has allowed researchers to study phenomena occurring in proteins on the femtosecond-to-minute timescale, taking advantage of many technical and methodological breakthroughs. Protein crystals of various sizes are presented to the X-ray beam in either a static or a moving medium. Photoactive proteins were naturally the initial systems to be studied in TR-SX experiments using pump–probe schemes, where the pump is a pulse of visible light. Other reaction initiations through small-molecule diffusion are gaining momentum. Here, selected examples of XFEL and synchrotron time-resolved crystallography studies will be used to highlight the specificities of the various instruments and methods with respect to time resolution, and are compared with cryo-trapping studies.

Mevalonate kinase is central to the isoprenoid biosynthesis pathway. Here, high-resolution X-ray crystal structures of two mevalonate kinases are presented: a eukaryotic protein from Ramazzottius varieornatus and an archaeal protein from Methanococcoides burtonii. Both enzymes possess the highly conserved motifs of the GHMP enzyme superfamily, with notable differences between the two enzymes in the N-terminal part of the structures. Biochemical characterization of the two enzymes revealed major differences in their sensitivity to geranyl pyrophosphate and farnesyl pyrophosphate, and in their thermal stabilities. This work adds to the understanding of the structural basis of enzyme inhibition and thermostability in mevalonate kinases.

A considerable bottleneck in serial crystallography at XFEL and synchrotron sources is the efficient production of large quantities of homogenous, well diffracting microcrystals. Efficient high-throughput screening of batch-grown microcrystals and the determination of ground-state structures from different conditions is thus of considerable value in the early stages of a project. Here, a highly sample-efficient methodology to measure serial crystallography data from microcrystals by raster scanning within standard in situ 96-well crystallization plates is described. Structures were determined from very small quantities of microcrystal suspension and the results were compared with those from other sample-delivery methods. The analysis of a two-dimensional batch crystallization screen using this method is also described as a useful guide for further optimization and the selection of appropriate conditions for scaling up microcrystallization.

The Azotobacter vinelandii FeSII protein forms an oxygen-resistant complex with the nitrogenase MoFe and Fe proteins. FeSII is an adrenodoxin-type ferredoxin that forms a dimer in solution. Previously, the crystal structure was solved [Schlesier et al. (2016), J. Am. Chem. Soc. 138, 239–247] with five copies in the asymmetric unit. One copy is a normal adrenodoxin domain that forms a dimer with its crystallographic symmetry mate. The other four copies are in an `open' conformation with a loop flipped out exposing the 2Fe–2S cluster. The open and closed conformations were interpreted as oxidized and reduced, respectively, and the large conformational change in the open configuration allowed binding to nitrogenase. Here, the structure of FeSII was independently solved in the same crystal form. The positioning of the atoms in the unit cell is similar to the earlier report. However, the interpretation of the structure is different. The `open' conformation is interpreted as the product of a crystallization-induced domain swap. The 2Fe–2S cluster is not exposed to solvent, but in the crystal its interacting helix is replaced by the same helix residues from a crystal symmetry mate. The domain swap is complicated, as it is unusual in being in the middle of the protein rather than at a terminus, and it creates arrangements of molecules that can be interpreted in multiple ways. It is also cautioned that crystal structures should be interpreted in terms of the contents of the entire crystal rather than of one asymmetric unit.

Advances in structural biology have relied heavily on synchrotron cryo-crystallography and cryogenic electron microscopy to elucidate biological processes and for drug discovery. However, disparities between cryogenic and room-temperature (RT) crystal structures pose challenges. Here, Cryo2RT, a high-throughput RT data-collection method from cryo-cooled crystals that leverages the cryo-crystallography workflow, is introduced. Tested on endothiapepsin crystals with four soaked fragments, thaumatin and SARS-CoV-2 3CLpro, Cryo2RT reveals unique ligand-binding poses, offers a comparable throughput to cryo-crystallography and eases the exploration of structural dynamics at various temperatures.

Several proteins from plant pathogenesis-related family 10 (PR10) are highly abundant in the latex of opium poppy and have recently been shown to play diverse and important roles in the biosynthesis of benzylisoquinoline alkaloids (BIAs). The recent determination of the first crystal structures of PR10-10 showed how large conformational changes in a surface loop and adjacent β-strand are coupled to the binding of BIA compounds to the central hydrophobic binding pocket. A more detailed analysis of these conformational changes is now reported to further clarify how ligand binding is coupled to the formation and cleavage of an intermolecular disulfide bond that is only sterically allowed when the BIA binding pocket is empty. To decouple ligand binding from disulfide-bond formation, each of the two highly conserved cysteine residues (Cys59 and Cys155) in PR10-10 was replaced with serine using site-directed mutagenesis. Crystal structures of the Cys59Ser mutant were determined in the presence of papaverine and in the absence of exogenous BIA compounds. A crystal structure of the Cys155Ser mutant was also determined in the absence of exogenous BIA compounds. All three of these crystal structures reveal conformations similar to that of wild-type PR10-10 with bound BIA compounds. In the absence of exogenous BIA compounds, the Cys59Ser and Cys155Ser mutants appear to bind an unidentified ligand or mixture of ligands that was presumably introduced during expression of the proteins in Escherichia coli. The analysis of conformational changes triggered by the binding of BIA compounds suggests a molecular mechanism coupling ligand binding to the disruption of an intermolecular disulfide bond. This mechanism may be involved in the regulation of biosynthetic reactions in plants and possibly other organisms.

β-Glucosidase from the thermophilic bacterium Caldicellulosiruptor saccharo­lyticus (Bgl1) has been denoted as having an attractive catalytic profile for various industrial applications. Bgl1 catalyses the final step of in the decomposition of cellulose, an unbranched glucose polymer that has attracted the attention of researchers in recent years as it is the most abundant renewable source of reduced carbon in the biosphere. With the aim of enhancing the thermostability of Bgl1 for a broad spectrum of biotechnological processes, it has been subjected to structural studies. Crystal structures of Bgl1 and its complex with glucose were determined at 1.47 and 1.95 Å resolution, respectively. Bgl1 is a member of glycosyl hydrolase family 1 (GH1 superfamily, EC 3.2.1.21) and the results showed that the 3D structure of Bgl1 follows the overall architecture of the GH1 family, with a classical (β/α)8 TIM-barrel fold. Comparisons of Bgl1 with sequence or structural homologues of β-glucosidase reveal quite similar structures but also unique structural features in Bgl1 with plausible functional roles.

Our study compares short-range order parameters refined from the diffuse scattering in single-crystal X-ray and single-crystal electron diffraction data. Nb0.84CoSb was chosen as a reference material. The correlations between neighbouring vacancies and the displacements of Sb and Co atoms were refined from the diffuse scattering using a Monte Carlo refinement in DISCUS. The difference between the Sb and Co displacements refined from the diffuse scattering and the Sb and Co displacements refined from the Bragg reflections in single-crystal X-ray diffraction data is 0.012 (7) Å for the refinement on diffuse scattering in single-crystal X-ray diffraction data and 0.03 (2) Å for the refinement on the diffuse scattering in single-crystal electron diffraction data. As electron diffraction requires much smaller crystals than X-ray diffraction, this opens up the possibility of refining short-range order parameters in many technologically relevant materials for which no crystals large enough for single-crystal X-ray diffraction are available.

The discovery of lytic polysaccharide monooxygenases (LPMOs), a family of copper-dependent enzymes that play a major role in polysaccharide degradation, has revealed the importance of oxidoreductases in the biological utilization of biomass. In fungi, a range of redox proteins have been implicated as working in harness with LPMOs to bring about polysaccharide oxidation. In bacteria, less is known about the interplay between redox proteins and LPMOs, or how the interaction between the two contributes to polysaccharide degradation. We therefore set out to characterize two previously unstudied proteins from the shipworm symbiont Teredinibacter turnerae that were initially identified by the presence of carbohydrate binding domains appended to uncharacterized domains with probable redox functions. Here, X-ray crystal structures of several domains from these proteins are presented together with initial efforts to characterize their functions. The analysis suggests that the target proteins are unlikely to function as LPMO electron donors, raising new questions as to the potential redox functions that these large extracellular multi-haem-containing c-type cytochromes may perform in these bacteria.

An X-ray absorption spectroscopy (XAS) electrochemical cell was used to collect high-quality XAS measurements of N-truncated Cu:amyloid-β (Cu:Aβ) samples under near-physiological conditions. N-truncated Cu:Aβ peptide complexes contribute to oxidative stress and neurotoxicity in Alzheimer's patients' brains. However, the redox properties of copper in different Aβ peptide sequences are inconsistent. Therefore, the geometry of binding sites for the copper binding in Aβ4–8/12/16 was determined using novel advanced extended X-ray absorption fine structure (EXAFS) analysis. This enables these peptides to perform redox cycles in a manner that might produce toxicity in human brains. Fluorescence XAS measurements were corrected for systematic errors including defective-pixel data, monochromator glitches and dispersion of pixel spectra. Experimental uncertainties at each data point were measured explicitly from the point-wise variance of corrected pixel measurements. The copper-binding environments of Aβ4–8/12/16 were precisely determined by fitting XAS measurements with propagated experimental uncertainties, advanced analysis and hypothesis testing, providing a mechanism to pursue many similarly complex questions in bioscience. The low-temperature XAS measurements here determine that CuII is bound to the first amino acids in the high-affinity amino-terminal copper and nickel (ATCUN) binding motif with an oxygen in a tetragonal pyramid geometry in the Aβ4–8/12/16 peptides. Room-temperature XAS electrochemical-cell measurements observe metal reduction in the Aβ4–16 peptide. Robust investigations of XAS provide structural details of CuII binding with a very different bis-His motif and a water oxygen in a quasi-tetrahedral geometry. Oxidized XAS measurements of Aβ4–12/16 imply that both CuII and CuIII are accommodated in an ATCUN-like binding site. Hypotheses for these CuI, CuII and CuIII geometries were proven and disproven using the novel data and statistical analysis including F tests. Structural parameters were determined with an accuracy some tenfold better than literature claims of past work. A new protocol was also developed using EXAFS data analysis for monitoring radiation damage. This gives a template for advanced analysis of complex biosystems.

Bacterial ABC toxin complexes (Tcs) comprise three core proteins: TcA, TcB and TcC. The TcA protein forms a pentameric assembly that attaches to the surface of target cells and penetrates the cell membrane. The TcB and TcC proteins assemble as a heterodimeric TcB–TcC subcomplex that makes a hollow shell. This TcB–TcC subcomplex self-cleaves and encapsulates within the shell a cytotoxic `cargo' encoded by the C-terminal region of the TcC protein. Here, we describe the structure of a previously uncharacterized TcC protein from Yersinia entomophaga, encoded by a gene at a distant genomic location from the genes encoding the rest of the toxin complex, in complex with the TcB protein. When encapsulated within the TcB–TcC shell, the C-terminal toxin adopts an unfolded and disordered state, with limited areas of local order stabilized by the chaperone-like inner surface of the shell. We also determined the structure of the toxin cargo alone and show that when not encapsulated within the shell, it adopts an ADP-ribosyltransferase fold most similar to the catalytic domain of the SpvB toxin from Salmonella typhimurium. Our structural analysis points to a likely mechanism whereby the toxin acts directly on actin, modifying it in a way that prevents normal polymerization.

Here, a machine-learning method based on a kinetically informed neural network (NN) is introduced. The proposed method is designed to analyze a time series of difference electron-density maps from a time-resolved X-ray crystallographic experiment. The method is named KINNTREX (kinetics-informed NN for time-resolved X-ray crystallography). To validate KINNTREX, multiple realistic scenarios were simulated with increasing levels of complexity. For the simulations, time-resolved X-ray data were generated that mimic data collected from the photocycle of the photoactive yellow protein. KINNTREX only requires the number of intermediates and approximate relaxation times (both obtained from a singular valued decomposition) and does not require an assumption of a candidate mechanism. It successfully predicts a consistent chemical kinetic mechanism, together with difference electron-density maps of the intermediates that appear during the reaction. These features make KINNTREX attractive for tackling a wide range of biomolecular questions. In addition, the versatility of KINNTREX can inspire more NN-based applications to time-resolved data from biological macromolecules obtained by other methods.

Carbonic anhydrase (CA) was among the first proteins whose X-ray crystal structure was solved to atomic resolution. CA proteins have essentially the same fold and similar active centers that differ in only several amino acids. Primary sulfonamides are well defined, strong and specific binders of CA. However, minor variations in chemical structure can significantly alter their binding properties. Over 1000 sulfonamides have been designed, synthesized and evaluated to understand the correlations between the structure and thermodynamics of their binding to the human CA isozyme family. Compound binding was determined by several binding assays: fluorescence-based thermal shift assay, stopped-flow enzyme activity inhibition assay, isothermal titration calorimetry and competition assay for enzyme expressed on cancer cell surfaces. All assays have advantages and limitations but are necessary for deeper characterization of these protein–ligand interactions. Here, the concept and importance of intrinsic binding thermodynamics is emphasized and the role of structure–thermodynamics correlations for the novel inhibitors of CA IX is discussed – an isozyme that is overexpressed in solid hypoxic tumors, and thus these inhibitors may serve as anticancer drugs. The abundant structural and thermodynamic data are assembled into the Protein–Ligand Binding Database to understand general protein–ligand recognition principles that could be used in drug discovery.

Stimulated by informal conversations at the XVII International Small Angle Scattering (SAS) conference (Traverse City, 2017), an international team of experts undertook a round-robin exercise to produce a large dataset from proteins under standard solution conditions. These data were used to generate consensus SAS profiles for xylose isomerase, urate oxidase, xylanase, lysozyme and ribonuclease A. Here, we apply a new protocol using maximum likelihood with a larger number of the contributed datasets to generate improved consensus profiles. We investigate the fits of these profiles to predicted profiles from atomic coordinates that incorporate different models to account for the contribution to the scattering of water molecules of hydration surrounding proteins in solution. Programs using an implicit, shell-type hydration layer generally optimize fits to experimental data with the aid of two parameters that adjust the volume of the bulk solvent excluded by the protein and the contrast of the hydration layer. For these models, we found the error-weighted residual differences between the model and the experiment generally reflected the subsidiary maxima and minima in the consensus profiles that are determined by the size of the protein plus the hydration layer. By comparison, all-atom solute and solvent molecular dynamics (MD) simulations are without the benefit of adjustable parameters and, nonetheless, they yielded at least equally good fits with residual differences that are less reflective of the structure in the consensus profile. Further, where MD simulations accounted for the precise solvent composition of the experiment, specifically the inclusion of ions, the modelled radius of gyration values were significantly closer to the experiment. The power of adjustable parameters to mask real differences between a model and the structure present in solution is demonstrated by the results for the conformationally dynamic ribonuclease A and calculations with pseudo-experimental data. This study shows that, while methods invoking an implicit hydration layer have the unequivocal advantage of speed, care is needed to understand the influence of the adjustable parameters. All-atom solute and solvent MD simulations are slower but are less susceptible to false positives, and can account for thermal fluctuations in atomic positions, and more accurately represent the water molecules of hydration that contribute to the scattering profile.

Light–oxygen–voltage (LOV) domains are small photosensory flavoprotein modules that allow the conversion of external stimuli (sunlight) into intra­cellular signals responsible for various cell behaviors (e.g. phototropism and chloro­plast relocation). This ability relies on the light-induced formation of a covalent thio­ether adduct between a flavin chromophore and a reactive cysteine from the protein environment, which triggers a cascade of structural changes that result in the activation of a serine/threonine (Ser/Thr) kinase. Recent developments in time-resolved crystallography may allow the activation cascade of the LOV domain to be observed in real time, which has been elusive. In this study, we report a robust protocol for the production and stable delivery of microcrystals of the LOV domain of phototropin Phot-1 from Chlamydomonas reinhardtii (CrPhotLOV1) with a high-viscosity injector for time-resolved serial synchrotron crystallography (TR-SSX). The detailed process covers all aspects, from sample optimization to data collection, which may serve as a guide for soluble protein preparation for TR-SSX. In addition, we show that the crystals obtained preserve the photoreactivity using infrared spectroscopy. Furthermore, the results of the TR-SSX experiment provide high-resolution insights into structural alterations of CrPhotLOV1 from Δt = 2.5 ms up to Δt = 95 ms post-photoactivation, including resolving the geometry of the thio­ether adduct and the C-terminal region implicated in the signal transduction process.

Reaching beyond the commonly used spherical atomic electron density model allows one to greatly improve the accuracy of hydrogen atom structural param­eters derived from X-ray data. However, the effects of atomic asphericity are less explored for electron diffraction data. In this work, Hirshfeld atom refinement (HAR), a method that uses an accurate description of electron density by quantum mechanical calculation for a system of interest, was applied for the first time to the kinematical refinement of electron diffraction data. This approach was applied here to derive the structure of ordinary hexagonal ice (Ih). The effect of introducing HAR is much less noticeable than in the case of X-ray refinement and it is largely overshadowed by dynamical scattering effects. It led to only a slight change in the O—H bond lengths (shortening by 0.01 Å) compared with the independent atom model (IAM). The average absolute differences in O—H bond lengths between the kinematical refinements and the reference neutron structure were much larger: 0.044 for IAM and 0.046 Å for HAR. The refinement results changed considerably when dynamical scattering effects were modelled – with extinction correction or with dynamical refinement. The latter led to an improvement of the O—H bond length accuracy to 0.021 Å on average (with IAM refinement). Though there is a potential for deriving more accurate structures using HAR for electron diffraction, modelling of dynamical scattering effects seems to be a necessary step to achieve this. However, at present there is no software to support both HAR and dynamical refinement.

3D electron diffraction (3DED) is increasingly employed to determine molec­ular and crystal structures from micro-crystals. Indomethacin is a well known, marketed, small-molecule non-steroidal anti-inflammatory drug with eight known polymorphic forms, of which four structures have been elucidated to date. Using 3DED, we determined the structure of a new ninth polymorph, σ, found within an amorphous solid dispersion, a product formulation sometimes used for active pharmaceutical ingredients with poor aqueous solubility. Subsequently, we found that σ indomethacin can be produced from direct solvent evaporation using di­chloro­methane. These results demonstrate the relevance of 3DED within drug development to directly probe product formulations.

MltG, a membrane-bound lytic transglycosyl­ase, has roles in terminating glycan polymerization in peptidoglycan and incorporating glycan chains into the cell wall, making it significant in bacterial cell-wall biosynthesis and remodeling. This study provides the first reported MltG structure from Mycobacterium abscessus (maMltG), a superbug that has high antibiotic resistance. Our structural and biochemical analyses revealed that MltG has a flexible peptidoglycan-binding domain and exists as a monomer in solution. Further, the putative active site of maMltG was disclosed using structural analysis and sequence comparison. Overall, this study contributes to our understanding of the transglycosyl­ation reaction of the MltG family, aiding the design of next-generation antibiotics targeting M. abscessus.

SnGe4N4O4 was synthesized at high pressure (16 and 20 GPa) and high temperature (1200 and 1500°C) in a large-volume press. Powder X-ray diffraction experiments using synchrotron radiation indicate that the derived samples are mixtures of known and unknown phases. However, the powder X-ray diffraction patterns are not sufficient for structural characterization. Transmission electron microscopy studies reveal crystals of several hundreds of nanometres in size with different chemical composition. Among them, crystals of a previously unknown phase with stoichiometry SnGe4N4O4 were detected and investigated using automated diffraction tomography (ADT), a three-dimensional electron diffraction method. Via ADT, the crystal structure could be determined from single nanocrystals in space group P63mc, exhibiting a nolanite-type structure. This was confirmed by density functional theory calculations and atomic resolution scanning transmission electron microscopy images. In one of the syntheses runs a rhombohedral 6R polytype of SnGe4N4O4 could be found together with the nolanite-type SnGe4N4O4. The structure of this polymorph was solved as well using ADT.

The crystal structure of the title compound {systematic name: (4S,4aS,5aR,12aR)-4,7-bis­(di­methyl­amino)-9-[(2,2-di­methyl­propyl­amino)­meth­yl]-1,10,11,12a-tetra­hydroxy-3,12-dioxo-4a,5,5a,6-tetra­hydro-4H-tetra­cene-2-carb­oxamide dihydrate, C29H40N4O7·2H2O} has been solved and refined using synchrotron X-ray powder diffraction data: it crystallizes in space group R3 with a = 24.34430 (7), c = 14.55212 (4) Å, V = 7468.81 (2) Å3 and Z = 9. Most of the hydrogen bonds are intra­molecular, but two classical N—H⋯O inter­molecular hydrogen bonds (along with probable weak C—H⋯O and C—H⋯N hydrogen bonds) link the mol­ecules into a three-dimensional framework. The framework contains voids, which contain disordered water mol­ecules. Keto–enol tautomerism is apparently important in this mol­ecule, and the exact mol­ecular structure is ambiguous.

This title compound, C20H26O2, was isolated from the benzene fraction of the stem bark of Staudtia kamerunensis Warb. (Myristicaceae) using column chromatography techniques over silica gel. The compound was fully characterized by single-crystal X-ray diffraction, one and two-dimensional NMR spectroscopy, IR and MS spectrometry. The compound has two fused cyclo­hexane rings attached to a benzene ring, with a carb­oxy­lic acid on C-4. This cyclo­hexene ring has a chair conformation while the other adopts a half-chair conformation. The benzene ring is substituted with a propenyl moiety. The structure is characterized by inter­molecular O—H⋯O hydrogen bonds, two C—H⋯O intra­molecular hydrogen bonds and two C—H⋯π inter­actions. The mol­ecular structure confirms previous studies carried out by spectroscopic techniques.

The X-ray crystal structure data of 12-α-fluoro-3β-hy­droxy­olean-28,13β-olide methanol hemisolvate, 2C30H47FO3·CH3OH, (1), and 12-α-fluoro-3β-hy­droxy­taraxer-28,14β-olide methanol hemisolvate, 2C30H47FO3·CH3OH, (2), are described. The fluoro­lactonization of oleanolic acid using SelectfluorTM yielded a mixture of the six-membered δ-lactone (1) and the unusual seven-membered γ-lactone (2) following a 1,2-shift of methyl C-27 from C-14 to C-13.

Characterization of a material structure with pair distribution function (PDF) analysis typically involves refining a structure model against an experimental data set, but finding or constructing a suitable atomic model for PDF modelling can be an extremely labour-intensive task, requiring carefully browsing through large numbers of possible models. Presented here is POMFinder, a machine learning (ML) classifier that rapidly screens a database of structures, here polyoxometallate (POM) clusters, to identify candidate structures for PDF data modelling. The approach is shown to identify suitable POMs from experimental data, including in situ data collected with fast acquisition times. This automated approach has significant potential for identifying suitable models for structure refinement to extract quantitative structural parameters in materials chemistry research. POMFinder is open source and user friendly, making it accessible to those without prior ML knowledge. It is also demonstrated that POMFinder offers a promising modelling framework for combined modelling of multiple scattering techniques.

X-ray diffraction from dislocation half-loops consisting of a misfit segment with two threading arms extending from it to the surface is calculated by the Monte Carlo method. The diffraction profiles and reciprocal space maps are controlled by the ratio of the total lengths of the misfit and the threading segments of the half-loops. A continuous transformation from the diffraction characteristic of misfit dislocations to that of threading dislocations with increasing thickness of epitaxial film is studied. Diffraction from dislocations with edge- and screw-type threading arms is considered and the contributions of the two types of dislocations are compared.

In addressing the challenges faced by laboratories and universities with limited (or no) cryo-electron microscopy (cryo-EM) infrastructure, the ESRF, in collaboration with the Grenoble Institute for Structural Biology (IBS), has implemented the cryo-EM Solution-to-Structure (SOS) pipeline. This inclusive process, spanning grid preparation to high-resolution data collection, covers single-particle analysis and cryo-electron tomography (cryo-ET). Accessible through a rolling access route, proposals undergo scientific merit and technical feasibility evaluations. Stringent feasibility criteria demand robust evidence of sample homogeneity. Two distinct entry points are offered: users can either submit purified protein samples for comprehensive processing or initiate the pipeline with already vitrified cryo-EM grids. The SOS pipeline integrates negative stain imaging (exclusive to protein samples) as a first quality step, followed by cryo-EM grid preparation, grid screening and preliminary data collection for single-particle analysis, or only the first two steps for cryo-ET. In both cases, if the screening steps are successfully completed, high-resolution data collection will be carried out using a Titan Krios microscope equipped with a latest-generation direct electron counting detector coupled to an energy filter. The SOS pipeline thus emerges as a comprehensive and efficient solution, further democratizing access to cryo-EM research.

Analysis of small-angle scattering (SAS) data requires intensive modeling to infer and characterize the structures present in a sample. This iterative improvement of models is a time-consuming process. Presented here is Scattering Equation Builder (SEB), a C++ library that derives exact analytic expressions for the form factors of complex composite structures. The user writes a small program that specifies how the sub-units should be linked to form a composite structure and calls SEB to obtain an expression for the form factor. SEB supports e.g. Gaussian polymer chains and loops, thin rods and circles, solid spheres, spherical shells and cylinders, and many different options for how these can be linked together. The formalism behind SEB is presented and simple case studies are given, such as block copolymers with different types of linkage, as well as more complex examples, such as a random walk model of 100 linked sub-units, dendrimers, polymers and rods attached to the surfaces of geometric objects, and finally the scattering from a linear chain of five stars, where each star is built up of four diblock copolymers. These examples illustrate how SEB can be used to develop complex models and hence reduce the cost of analyzing SAS data.

This article describes a correction procedure for the removal of indirect background contributions to measured small-angle X-ray scattering patterns. The high scattering power of a sample in the ultra-small-angle region may serve as a secondary source for a window placed in front of the detector. The resulting secondary scattering appears as a sample-dependent background in the measured pattern that cannot be directly subtracted. This is an intricate problem in measurements at ultra-low angles, which can significantly reduce the useful dynamic range of detection. Two different procedures are presented to retrieve the real scattering profile of the sample.

The pair angle distribution function (PADF) is a three- and four-atom correlation function that characterizes the local angular structure of disordered materials, particles or nanocrystalline materials. The PADF can be measured using X-ray or electron fluctuation diffraction data, which can be collected by scanning or flowing a structurally disordered sample through a focused beam. It is a natural generalization of established pair distribution methods, which do not provide angular information. The software package pypadf provides tools to calculate the PADF from fluctuation diffraction data. The package includes tools for calculating the intensity correlation function, which is a necessary step in the PADF calculation and also the basis for other fluctuation scattering analysis techniques.

The capillary wave model of a liquid surface predicts both the X-ray specular reflection and the diffuse scattering around it. A quantitative method is presented to obtain the X-ray reflectivity (XRR) from a liquid surface through the diffuse scattering data around the specular reflection measured using a grazing incidence X-ray off-specular scattering (GIXOS) geometry at a fixed horizontal offset angle with respect to the plane of incidence. With this approach the entire Qz-dependent reflectivity profile can be obtained at a single, fixed incident angle. This permits a much faster acquisition of the profile than with conventional reflectometry, where the incident angle must be scanned point by point to obtain a Qz-dependent profile. The XRR derived from the GIXOS-measured diffuse scattering, referred to in this paper as pseudo-reflectivity, provides a larger Qz range compared with the reflectivity measured by conventional reflectometry. Transforming the GIXOS-measured diffuse scattering profile to pseudo-XRR opens up the GIXOS method to widely available specular XRR analysis software tools. Here the GIXOS-derived pseudo-XRR is compared with the XRR measured by specular reflectometry from two simple vapor–liquid interfaces at different surface tension, and from a hexadecyltri­methyl­ammonium bromide monolayer on a water surface. For the simple liquids, excellent agreement (beyond 11 orders of magnitude in signal) is found between the two methods, supporting the approach of using GIXOS-measured diffuse scattering to derive reflectivities. Pseudo-XRR obtained at different horizontal offset angles with respect to the plane of incidence yields indistinguishable results, and this supports the robustness of the GIXOS-XRR approach. The pseudo-XRR method can be extended to soft thin films on a liquid surface, and criteria are established for the applicability of the approach.

Presented and discussed here is the implementation of a software solution that provides prompt X-ray diffraction data analysis during fast dynamic compression experiments conducted within the dynamic diamond anvil cell technique. It includes efficient data collection, streaming of data and metadata to a high-performance cluster (HPC), fast azimuthal data integration on the cluster, and tools for controlling the data processing steps and visualizing the data using the DIOPTAS software package. This data processing pipeline is invaluable for a great number of studies. The potential of the pipeline is illustrated with two examples of data collected on ammonia–water mixtures and multiphase mineral assemblies under high pressure. The pipeline is designed to be generic in nature and could be readily adapted to provide rapid feedback for many other X-ray diffraction techniques, e.g. large-volume press studies, in situ stress/strain studies, phase transformation studies, chemical reactions studied with high-resolution diffraction etc.

Using the well known Rn ratio method, a protocol has been elaborated for determining the lattice direction for the 15 most common cubic zone axis spot patterns. The method makes use of the lengths of the three shortest reciprocal-lattice vectors in each pattern and the angles between them. No prior pattern calibration is required for the method to work, as the Rn ratio method is based entirely on geometric relationships. In the first step the pattern is assigned to one of three possible pattern types according to the angles that are measured between the three reciprocal-lattice vectors. The lattice direction [uvw] and possible Bravais type(s) and Laue indices of the corresponding reflections can then be determined by using lookup tables. In addition to determining the lattice direction, this simple geometric analysis allows one to distinguish between the P, I and F Bravais lattices for spot patterns aligned along [013], [112], [114] and [233]. Moreover, the F lattice can always be uniquely identified from the [011] and [123] patterns.

Predicting crystal symmetry simply from chemical composition has remained challenging. Several machine-learning approaches can be employed, but the predictive value of popular crystallographic databases is relatively modest due to the paucity of data and uneven distribution across the 230 space groups. In this work, virtually all crystallographic information available to science has been compiled and used to train and test multiple machine-learning models. Composition-driven random-forest classification relying on a large set of descriptors showed the best performance. The predictive models for crystal system, Bravais lattice, point group and space group of inorganic compounds are made publicly available as easy-to-use software downloadable from https://gitlab.com/vishsoft/cosy.

High-energy X-ray diffraction methods can non-destructively map the 3D microstructure and associated attributes of metallic polycrystalline engineering materials in their bulk form. These methods are often combined with external stimuli such as thermo-mechanical loading to take snapshots of the evolving microstructure and attributes over time. However, the extreme data volumes and the high costs of traditional data acquisition and reduction approaches pose a barrier to quickly extracting actionable insights and improving the temporal resolution of these snapshots. This article presents a fully automated technique capable of rapidly detecting the onset of plasticity in high-energy X-ray microscopy data. The technique is computationally faster by at least 50 times than the traditional approaches and works for data sets that are up to nine times sparser than a full data set. This new technique leverages self-supervised image representation learning and clustering to transform massive data sets into compact, semantic-rich representations of visually salient characteristics (e.g. peak shapes). These characteristics can rapidly indicate anomalous events, such as changes in diffraction peak shapes. It is anticipated that this technique will provide just-in-time actionable information to drive smarter experiments that effectively deploy multi-modal X-ray diffraction methods spanning many decades of length scales.

Here, a morphologically based approach is used for the in situ characterization of 3D growth rates of facetted crystals from the solution phase. Crystal images of single crystals of the β-form of l-glutamic acid are captured in situ during their growth at a relative supersaturation of 1.05 using transmission optical microscopy. The crystal growth rates estimated for both the {101} capping and {021} prismatic faces through image processing are consistent with those determined using reflection light mode [Jiang, Ma, Hazlehurst, Ilett, Jackson, Hogg & Roberts (2024). Cryst. Growth Des. 24, 3277–3288]. The growth rate in the {010} face is, for the first time, estimated from the shadow widths of the {021} prismatic faces and found to be typically about half that of the {021} prismatic faces. Analysis of the 3D shape during growth reveals that the initial needle-like crystal morphology develops during the growth process to become more tabular, associated with the Zingg factor evolving from 2.9 to 1.7 (>1). The change in relative solution supersaturation during the growth process is estimated from calculations of the crystal volume, offering an alternative approach to determine this dynamically from visual observations.

The Takagi–Taupin equations are solved in their simplest form (zero deformation) to obtain the Bragg-diffracted and transmitted complex amplitudes. The case of plane-parallel crystal plates is discussed using a matrix model. The equations are implemented in an open-source Python library crystalpy adapted for numerical applications such as crystal reflectivity calculations and ray tracing.

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"Red Band Society," premieres on Fox September 17th, starring Octavia Spencer, Charlie Rowe and Nolan Sotillo.; Credit: Fox Television Studios

The Los Angeles County Metropolitan Transportation Authority is pulling ads for the Fox television show "Red Band Society" from nearly 200 buses amid complaints they are racist and offensive to women.

The ads show the ensemble cast's members in front of a wall with graffiti describing their characters.

A denigrating word for a woman is used to describe the show's star, Octavia Spencer's character.

The Los Angeles Times reports transit officials began pulling the ads on Wednesday. They had been up for five weeks.

The Red Band Society also shared the ad on its Facebook page in August. 

Facebook: #RedBandSociety ad

But it's since edited it to look like this.

Photo: New ad via Facebook

Protesters who attended Thursday's transit agency board meeting complained the depiction of Spencer's character is racist and offensive to women.

The actress, who plays a nurse in the hospital drama, is black.

She won a supporting actress Oscar for her role in "The Help."

The relationship between pianist Justin Kauflin and trumpeter Clark Terry is at the heart of the documentary, "Keep On Keepin' On."; Credit: COURTESY OF RADiUS-TWC

Trumpeter Clark Terry played in Count Basie's and Duke Ellington's bands. He was the first African American hired for The Tonight Show band. He mentored the teenage prodigies Miles Davis and Quincy Jones. But Terry isn't as well known as you might think he'd be. 

Thanks to the new documentary, "Keep On Keepin' On," you can see Clark Terry — or C.T., as everyone calls him — in action. The film tells the story of Terry's early love of the trumpet, his quick rise through the jazz ranks, and how he's devoted much of his life to inspiring other musicians — all with a sparkle in his eye.

The movie is directed by first time filmmaker Alan Hicks and made on a shoestring budget. Hicks is himself a drummer and had been one of Terry's students. Originally it was going to be a short film about Terry and Hicks' relationship, funded by the Australian Broadcasting Company. (Hicks is from Australia.) When that financing fell through, Hicks improvised. Determined to tell the world about Terry, he and a childhood buddy, Adam Hart, decided to do it themselves — despite having no filmmaking experience. They bought a camera and plane tickets to the U.S. and began following Terry.

For many years their schedule was to shoot until they ran out of funds, usually about three months, work for a few months to save more money, then go back to shooting. To demonstrate how Terry mentors his students, they followed one young man in particular. Justin Kauflin is a blind jazz pianist with stage fright who would spend days and nights practicing at Terry's bedside. Over the course of the film, as we learn about Terry's past, we see the aging trumpeter in the present (he's now 93) — struggling with advanced diabetes, but always composing riffs from his bed late into the night.  

In one moving scene, Kauflin is riddled with anxiety as he prepares to compete in the Thelonious Monk International Jazz competition. Terry sends him an audio letter and some lucky socks for inspiration.

Years into the project, when Quincy Jones came to visit Terry, he met Kauflin and the filmmakers. Eventually Jones signed on as an executive producer of "Keep On Keepin' On" — as is only fitting given that, at age 13, he'd been Terry's first student.

Jones, Hicks and Kauflin spoke with The Frame about Terry and his unparalleled talent as a musician and as a mentor.

Source: Streetwise Reports 11/07/2024

Jericho Energy Ventures Inc. (JEV:TSX.V; JROOF:OTC; JLM:FRA) has announced a strategic move to spin off its hydrogen solutions platform into a separate entity. The new entity, to be named Hydrogen Technologies Corp. (HTC), was approved by the company's board of directors. The intention is to create two specialized companies focusing on hydrogen technology and traditional energy assets, respectively. Each Jericho Energy shareholder will retain their Jericho shares while receiving shares of the new HTC entity on a pro-rata basis in consideration of the transfer of Jericho's hydrogen assets.

The planned transaction, still subject to regulatory and shareholder approvals, aims to allow both companies to focus on their distinct markets and strategies. Jericho Energy expects this restructuring to enable each company to operate with tailored capital structures and investment plans, positioning them for growth within their specific sectors. The final terms of the spinout will be detailed in a management information circular to be shared with shareholders before they vote on the proposal.

Approval processes for the spinout include a review by the TSX Venture Exchange, shareholder consent, and possibly court approval in British Columbia if the plan proceeds via a formal arrangement. Jericho's CEO, Brian Williamson, noted in the news release, "By separating our hydrogen platform, we can create two agile, focused companies . . . positioning them for long-term growth and success."

Jericho Energy, which will continue trading on the TSX Venture Exchange under the symbol JEV, will retain its traditional oil and gas assets following the separation. The company's annual general meeting on January 15, 2025, may serve as a venue for shareholder approval, or a separate meeting may be scheduled.

Hydrogen Energy and Clean Tech

Energy Storage, in its November 5 report, underscored the growth potential for green hydrogen in the U.S. Supported by the government's US$7 billion Regional Clean Hydrogen Hubs program, this program aimed to boost clean hydrogen production and reduce costs. The report noted that the Mid-Atlantic Hydrogen Hub (MACH2) anticipated large-scale green hydrogen projects, generating over 20,000 jobs and incorporating hydrogen applications across sectors like steel, aviation, and maritime.

On November 6, Reuters reported that despite political shifts, U.S. clean energy momentum continues to be driven by federal tax credits and technology advancements. Renewable energy sources, including hydrogen, were identified as the fastest-growing segments on the power grid, benefiting from initiatives like the Inflation Reduction Act (IRA) and state mandates. Carl Fleming, a partner at McDermott Will & Emery, highlighted that "the jobs and the economic benefits have been so heavy in red states, it's hard to see an administration come in that says we don't like this." Although political challenges might impact renewable sectors like offshore wind, the trajectory of clean energy, including hydrogen, remained strong due to market demand and state-level support.

The International Energy Agency's (IEA) 2024 Global Hydrogen Review reported that global hydrogen demand reached 97 Mt (metric tons) in 2023. This demand was projected to approach 100 Mt in 2024. The IEA highlighted a rising focus on low-emissions hydrogen, particularly for refining and heavy industries. Although new applications in transport and energy storage accounted for less than 1% of global demand, industry interest grew, with chemical, refining, and shipping sectors making strides in contracting low-emissions hydrogen. The IEA also noted substantial investments in electrolyzer projects worldwide, with installed capacity expected to grow significantly.

Jericho's Catalysts

According to Jericho Energy's April 2024 investor presentation, the spinout of Hydrogen Technologies Corp. aligns with a broader strategy to drive advancements in hydrogen technology. Currently, an area experiencing significant momentum due to global energy transition efforts, the investor presentation highlights key growth drivers, including Jericho’s patented hydrogen-based boiler technology and emerging partnerships with institutions and companies across the hydrogen sector. [OWNERSHIP_CHART-7025]

The decision to separate hydrogen assets positions HTC to capture opportunities within the rapidly expanding hydrogen ecosystem, benefiting from policy support and rising market demand for green energy solutions. As part of its strategy, Jericho intends to leverage its expertise in traditional energy systems while directing resources to support innovation in hydrogen applications.

Ownership and Share Structure

Around 35% of Jericho's shares are held by management, insiders, and insider institutional investors, the company said. They include CEO Brian Williamson, who owns 1.19% or about 3.1 million shares; founder Allen Wilson, who owns 0.76% or about 1.97 million shares; and board member Nicholas Baxter, who owns 0.44%, or about 1.14 million shares, according to Refinitiv' latest research.

Around 10% of shares are held by non-insider institutions, and approximately 55% are in retail, the company said.

On March 6, 2023, JEV completed an insider-led private placement financing, above the current share price, for gross proceeds of CA$2.23 million.

JEV's market cap is CA$25.19 million, and it trades in a 52-week range of CA$0.07 and CA$0.18. It has 259.75 million shares outstanding, approx.. 189.99 million floating.

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Important Disclosures:

1. As of the date of this article, officers and/or employees of Streetwise Reports LLC (including members of their household) own securities of Jericho Energy Ventures Inc.
2. James Guttman wrote this article for Streetwise Reports LLC and provides services to Streetwise Reports as an employee.
3. This article does not constitute investment advice and is not a solicitation for any investment. Streetwise Reports does not render general or specific investment advice and the information on Streetwise Reports should not be considered a recommendation to buy or sell any security. Each reader is encouraged to consult with his or her personal financial adviser and perform their own comprehensive investment research. By opening this page, each reader accepts and agrees to Streetwise Reports' terms of use and full legal disclaimer. Streetwise Reports does not endorse or recommend the business, products, services or securities of any company.

For additional disclosures, please click here.

( Companies Mentioned: JEV:TSX.V; JROOF:OTC; JLM:FRA, )

Full Text:

Scientists have recovered the first genetic data from an extinct bird in the Caribbean, thanks to the remarkably preserved bones of a Creighton's caracara in a flooded sinkhole on Great Abaco Island in the Bahamas. Studies of ancient DNA from tropical birds have faced two formidable obstacles. Organic material quickly degrades when exposed to heat, light and oxygen. And birds' lightweight, hollow bones break easily, accelerating the decay of the DNA within. But the dark, oxygen-free depths of a 100-foot blue hole known as Sawmill Sink provided ideal preservation conditions for the bones of Caracara creightoni, a species of large carrion-eating falcon that disappeared soon after humans arrived in the Bahamas about 1,000 years ago. Florida Museum of Natural History researcher Jessica Oswald and her colleagues extracted and sequenced genetic material from the 2,500-year-old C. creightoni femur. Because ancient DNA is often fragmented or missing, the team had modest expectations for what they would find –- maybe one or two genes. But instead, the bone yielded 98.7% of the bird's mitochondrial genome, the DNA most living things inherit from their mothers. The mitochondrial genome showed that C. creightoni is closely related to the two remaining caracara species alive today: the crested caracara and the southern caracara. The three species last shared a common ancestor between 1.2 and 0.4 million years ago. "This project enhanced our understanding of the ecological and evolutionary implications of extinction, forged strong international partnerships, and trained the next generation of researchers," says Jessica Robin, a program director in National Science Foundation's Office of International Science and Engineering, which funded the study.

Image credit: Florida Museum photo by Kristen Grace

UK-based alternative banking provider Suits Me has announced the acquisition of Engage Card customers from Solaris, with the company focusing on scaling financial inclusion in the region. 

Source: Streetwise Reports 11/05/2024

Dolly Varden Silver Corp. (DV:TSX.V; DOLLF:OTCQX) released results from five drill holes from its completed 2024 drilling program at its Kitsault Valley project in British Columbia's Golden Triangle.

In total, the program drilled 69 holes for 31,726 meters — 41 holes totaling more than 15,000 meters at the Dolly Varden area and 28 holes totaling more than 16,000 meters at Homestake Ridge.

Highlights of Monday's release include one hole from the Homestake Silver Deposit that found 12.23 grams per tonne gold (g/t Au) and 84 g/t silver (Ag) over 34.93 meters with high-grade breccia veins that included 166 g/t Au and 675 g/t Ag over 0.97 meters.

"The identification of a gold-rich, wide and high-grade area within the Homestake Silver Deposit is highly encouraging," said Chief Executive Officer Shawn Khunkhun. "Our geological team is encouraged by overlapping mineralizing phases of silver and gold-rich veins and breccias; the deposit remains open for expansion."

Technical Analyst Clive Maund, writing on Sunday, called Dolly Varden "one of the best pure silver companies around."

The stock's "breakout at end of last month/early this month was on big volume means it was genuine," Maund wrote.

The stock is at a "classic buy spot, although we should remain aware that it could zigzag a little lower over the short-term, but that said it looks like a strong buy here."

Highlights From Results

Highlights from the Homestake Silver Deposit include:

• Hole HR24-432: Mineralized envelope including veins: 8.85 g/t Au and 5 g/t Ag over 48.23 meters, including an internal zone of stronger breccia vein intervals grading 29.24 g/t Au and 16 g/t Ag over 13.94 meters, including one breccia vein grading 701 g/t Au and 184 g/t Ag over 0.54 meters.
• Hole HR24-435: Mineralized envelope including veins: 4.64 g/t Au and 38 g/t Ag over 100.80 meters, including an internal interval of stronger breccia vein mineralization grading 12.23 g/t Au and 84 g/t Ag over 34.93 meters. High-grade breccia veins include 166 g/t Au and 675 g/t Ag over 0.97 meters.
• Hole HR24-442: Vein breccia zone: 4.58 g/t Au over 9.95 meters, including 14.96 g/t Au over 1.69 meters.

"Results from the five holes in this release suggest that the plunge of mineralization at Homestake Silver has a similar orientation as the Homestake Main Deposit, located 300 meters to the northwest," the company said in a release. "The average grades within these core areas are higher, on a precious metal silver equivalent basis, than the average grade of the silver deposits at the Dolly Varden property further south, due to the increased gold content at the Homestake Ridge Deposits."

Technical Analyst Clive Maund, writing on Sunday, called Dolly Varden "one of the best pure silver companies around."

Drill holes HR24-442 and HR24-445 are step-outs and encountered the mineralized and altered structural corridor of Homestake Silver, the company said. Drill hole HR24-442 intersected a mineralized vein breccia stockwork zone grading 4.58 g/t Au over 9.95 meters, including individual breccias with stronger pyrite mineralization grading 14.96 g/t Au over 1.69 meters.

The Homestake Ridge deposits are interpreted as structurally controlled, multi-phase epithermal vein stockwork and vein breccia system hosted in Jurassic Hazelton volcanic rocks, Dolly Varden noted. Mineralization consists of pyrite plus galena and sphalerite with visible gold in a breccia matrix within a silica breccia vein system.

"The northwest orientation of the main Homestake structural trend appears to have numerous subparallel internal structures that are interpreted to form the controls for higher grade gold and silver shoots within a broader mineralized envelope at the Homestake Silver deposit," the company said. "The main structural corridor dips steeply to the northeast at Homestake Main and rolls to vertical or steeply southwest at Homestake Silver."

Analyst's Response: 'Boom'

Jeff Valks, Senior Analyst for The Gold Advisor newsletter, reacted to the results with the word "BOOM."

"Dolly Varden Silver reports more high-grade drill results from its 2024 exploration program at the Homestake Silver Deposit in British Columbia's Golden Triangle," he wrote on Monday. "Results from five drill holes have confirmed significant gold and silver mineralization in an area targeted within the plunge of a previously undrilled high-grade zone, signaling potential expansion opportunities."

Jeff Valks, Senior Analyst for The Gold Advisor newsletter, reacted to the results with the word "BOOM."

We look forward to the remaining results." Vaks wrote. "In the meantime, the stock is flat as I write but is up over 35% year-to-date. It's not too late to buy, it's down from its recent spike, and as (editor) Jeff (Clark) has said, this is a core holding for the silver bull market. Use a stink bid if you're looking for shares. Both Jeff and I hold long positions."

Analyst Marcus Giannini of Haywood Capital Markets noted in a recent research note that Dolly Varden continues to "push the margins of known high-grade mineralization" at the project.

Gianini gave the stock a Buy rating with a CA$2.40 per share target price. "We continue to view Dolly's high-grade endowment as an increasingly attractive target for larger North American-focused precious metal producers," he noted.

The Catalyst: Analysts Point to Patience

While it has chased the record highs gold has been setting this year, silver recently broke through US$35 per ounce, reflecting a year-to-date gain of about 47%. It has since settled but held to the "crucial US$32.50 level," according to Christopher Lewis of FX Empire on Monday.

"Keep in mind that this is a market that is extraordinarily volatile and, of course, will continue to be noisy over the next couple of days as we get election results in the United States," Lewis wrote. "And of course, we also get the Federal Reserve interest rate decision on Thursday, both of which could cause chaos."

Lewis said he thinks the "least likely path is lower."

"I still favor an upside move, but I recognize that we are definitely in a little bit of a holding pattern," he wrote. "Having said that, if we do see momentum to the upside, then there's really not a whole lot here that could keep this market from trying to challenge the (US$)35 level again, obviously, a large round psychologically significant figure, but we'll just have to wait and see how that plays out."

The most conductive element in nature, silver is used to coat electrical contacts in computers, phones, cars, and appliances. It's also an important element in solar technology.

Mordor Intelligence noted that the white metal is expected to register a compound annual growth rate (CAGR) of more than 5% between 2024 and 2029.

Newsletter editor Brien Lundin encouraged investors not to get discouraged, as any price drop-off is temporary, he said. He expects the silver price to soar when the U.S. Federal Reserve doubles down on its efforts to get interest rates much lower, he wrote on Oct. 23. [OWNERSHIP_CHART-5439]

Based on silver's charts, Ron Struthers of Struthers Resource Stock Report also predicted a major run-up in the silver price.

"Back in April or early May, I highlighted the breakout from a cup and handle formation and [that] that would lead to a major upside move. This is now confirmed," he wrote on Oct. 23.

Ownership and Share Structure

According to the company's latest corporate presentation, 50% of its stock is held by institutional investors, including Fidelity Management & Research Company LLC, Sprott Asset Management LP, U.S. Global Investors Inc., and Delbrook.

About 41% is with strategic investors, including 17% with Fury Gold Mines, 14% with Hecla, and Eric Sprott owns 10% himself.

The rest, 9%, is with retail and high-net-worth investors.

The company has 301.16 million outstanding shares. Its market cap is CA$380.72 million, and its 52-week trading range is CA$0.62–1.46 per share.

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Important Disclosures:

1. Dolly Varden Silver Corp. is a billboard sponsor of Streetwise Reports and pays SWR a monthly sponsorship fee between US$4,000 and US$5,000.
2. As of the date of this article, officers and/or employees of Streetwise Reports LLC (including members of their household) own securities of Dolly Varden Silver Corp.
3. Steve Sobek wrote this article for Streetwise Reports LLC and provides services to Streetwise Reports as an employee.
4. This article does not constitute investment advice and is not a solicitation for any investment. Streetwise Reports does not render general or specific investment advice and the information on Streetwise Reports should not be considered a recommendation to buy or sell any security. Each reader is encouraged to consult with his or her personal financial adviser and perform their own comprehensive investment research. By opening this page, each reader accepts and agrees to Streetwise Reports' terms of use and full legal disclaimer. Streetwise Reports does not endorse or recommend the business, products, services or securities of any company.

For additional disclosures, please click here.

( Companies Mentioned: DV:TSX.V; DOLLF:OTCQX, )

; Credit: /Joy Ho for NPR

Perhaps the only respite pandemic closures brought to my family — which includes two kids under age 6 — was freedom from the constant misery of dripping noses, sneezes and coughs. And statistics suggest we weren't the only ones who had fewer colds last year: With daycares and in-person schools closed and widespread use of masks and hand sanitizer in most communities, cases of many seasonal respiratory infections went down, and flu cases dropped off a cliff.

That reprieve might be ending. Social mixing has been starting up again in much of the U.S. and so have cases of garden-variety sniffles. The Centers for Disease Control and Prevention just warned physicians that RSV, a unpleasant respiratory virus, is surging right now in southern states. And it's not just happening in the U.S. — researchers in the U.K. and Hong Kong found that rhinovirus outbreaks spiked there, too, when COVID-19 lockdowns ended.

My family is at the vanguard of this trend. Right after Washington D.C. lifted its mask mandate a few weeks ago, both my kids got runny noses and coughs, and as soon as they tested negative for COVID-19, my pandemic fears were replaced by a familiar dread. I had visions of sleepless, cough-filled nights, dirty tissues everywhere, and — in short order — my own miserable cold.

"If someone in your house is sick, you're not only breathing in their sick air, you're touching those contaminated surfaces. You're having closer contact, you're having longer exposures," says Seema Lakdawala, a researcher at the University of Pittsburgh School of Medicine, who studies how influenza viruses transmit between people. It can start to feel inevitable that the whole family will get sick.

Take heart, my fellow parents-of-adorable-little-germ-machines! Lakdawala says many strategies we all picked up to fight COVID-19 can also stop the spread of many routine respiratory viruses. In fact, they may be even more effective against run-of-the-mill germs, since, unlike the viruses behind most colds, SARS-CoV2 was new to the human immune system.

Those strategies start with everyone keeping their children home from school, camp and playdates when they're sick and keeping up with any and all vaccinations against childhood illnesses. Beyond that, specialists in infectious disease transmission I consulted offer five more tips for keeping my family and yours healthier this summer.

Tip #1: Hang on to those masks

In pre-pandemic times, it might have seemed like a weird move to put on a mask during storytime with your drippy-nosed kid, but Dr. Tina Tan says that's her top tip. She's a professor of pediatrics at the Feinberg School of Medicine at Northwestern University and a pediatric infectious disease physician at Lurie Children's Hospital in Chicago.

When it comes to influenza, a rhinovirus, or any of the other respiratory bugs constantly circulating, "once these viruses touch your mucous membranes, whether it's your eyes, your nose or your mouth, you do have a chance of contracting it," says Tan. Masks help stop infectious particles and virus-filled droplets from getting into your body.

"You don't need a N95," Tan says. A light-weight surgical mask or homemade cloth mask can work as long as it has two or more layers. The mask-wearing also doesn't have to be constant. "If you're going to be face to face with them — they're sitting in your lap, you're reading to them, you're feeding them, etc. — then I would say wear a mask," Tan advises.

Even better, if it's not too uncomfortable for your sick child, have them wear a mask, Lakdawala says. "If your kids are old enough to wear a mask, that would probably be the best strategy, because then you're reducing the amount of virus-laden aerosols in the environment."

How long should you stay masked-up?

For most respiratory viruses, "the infectious period is probably similar to that of COVID," says Dr. Jennifer Shu, a pediatrician in Atlanta and medical editor of the American Academy of Pediatrics' site HealthyChildren.org. It might technically start a few days before symptoms begin and last for up to two weeks, but your sniffly kids are likely most contagious during those first runny-nosed days Shu says. "You could have kids over [age] 2 wear a mask for the first three or four days of symptoms," she suggests.

And if you can't bring yourself to wear a mask or put one on your child inside your own home to fight a cold, don't worry. Lakdawala has a few more ideas.

Tip #2: Air it out, space it out

When Lakdawala's 5- and 8-year-old kids get sick, "I open the windows, I turn on the fans, I get a lot more air circulation going on in the house," she says — that is, weather and allergies permitting, of course.

"A lot of these viruses tend to circulate more during the colder weather, so where you live is going to determine how much you can open your windows," Tan points out. But certainly, she says, "the better the ventilation, the less likely the viruses are going to get transmitted from one person to another."

What about buying HEPA filter air purifiers, or changing the filter in your heating and air conditioning system? "I would not suggest going out to purchase extra HEPA filters just for this purpose," says Dr. Ibukun Kalu, a pediatric infectious disease physician at Duke University. For hospitals that are treating very contagious and serious pathogens like tuberculosis or SARS-CoV2, those upgrades may be important, she says. "But for all of the other routine viruses, it's routine ventilation."

Kalu says you might also want to think strategically about creating some social distance — when it's possible — like strategically having the parent who tends not to get as sick provide the one-on-one care for the sick kid.

Obviously, you can't isolate a sick child in a room by themselves until they recover, but Lakdawala says not getting too close or for too long can help. When her kids are sick, "I do try to just not snuggle them — keep them a little bit at a distance."

Tip #3: Don't try to be a HAZMAT team

There's good news on the house-cleaning front. "Most of these viruses don't live on surfaces for very long periods of time," says Tan.

The research on exactly how long cold-causing rhinoviruses can survive on surfaces — and how likely they are to remain infectious — isn't definitive. As Dr. Donald Goldmann of Boston Children's Hospital poetically put it in The Pediatric Infectious Disease Journal a couple decades ago, "Despite many years of study, from the plains of Salisbury, to the hills of Virginia, to the collegiate environment of Madison, WI, the precise routes rhinovirus takes to inflict the misery of the common cold on a susceptible population remain controversial." That's still true today, doctors say.

There's some evidence that contaminated surfaces are not very important in the spread of colds. In one little study from the 1980s, a dozen healthy men played poker with cards and chips that "were literally gummy" from the secretions of eight other men who had been infected with a rhinovirus as part of the study. Even after 12 hours of poker, none of the healthy volunteers caught colds.

Shu's take home advice? Be methodical in your cleaning of often-touched surfaces (kitchen table, countertops and the like) with soap and water when everybody's healthy, and maybe add bleach wipes or other disinfectant when someone in your household has a cold. But don't panic.

Tan agrees. "Wipe down frequently-touched surfaces multiple times a day," she says. "But you don't have to go crazy and, like, scour everything down with bleach."

You also don't need to do a lot of extra laundry in hopes of eliminating germs on clothes, towels, dishtowels and the like — that can be exhausting and futile. Instead, just try to encourage kids who are sick to use their own towel — and do what you can to give towels a chance to dry out between uses. "Having some common sense and doing laundry every few days — washing your towels every few days and washing your sheets every couple of weeks — is probably good enough," Shu says. "You don't need to go overboard for run-of-the-mill viruses."

Don't fret that there are germs everywhere and you can't touch anything, says Lakdawala. "If I touch something, that -- in itself — is not infecting me," she notes. Instead, it's getting a certain amount of virus on our hands and then touching our own nose, eyes or mouth that can infect us. "If I just go wash my hands, that risk is gone," Lakdawala says.

You can also skip wearing gloves around the house. "People think that they are safe when they're wearing the gloves — and then they touch their face with their gloves [on]" and infect themselves, she says.

Instead, just make it a habit to wash your hands frequently.

Tip #4: Seriously, just wash your hands

"The same handwashing guidelines for COVID also apply for common respiratory illnesses," Shu says. That is: regular soap with warm water, lathered for about 20 seconds.

"The reason why 20 seconds is recommended is because some studies show that washing your hands shorter than that doesn't really get rid of germs." She warns that there hasn't been a whole lot of research on this, and 20 seconds is not a magic number. "But it is thought that anywhere from 15 to 30 seconds is probably good enough to get rid of most of the germs," she says. (Note: No need to drive your family crazy singing the birthday song twice — y'all have options.)

"Wash your hands before you eat, after you eat, after you go to the bathroom ... if you're changing your child's diaper, et cetera.," says Tan. "And if you're going to use hand sanitizer, it has to be at least 60% alcohol."

"Your hands are probably the most important source of transmission outside of someone really coughing or sneezing in your face," Kalu adds.

Tip #5: Don't give up, but do keep perspective

So, what if your beloved child does cough or sneeze in your face? Should you then forget all this stuff and just give in to the inevitable?

Don't give up, says Lakdawala. "Just because you got one large exposure in your mouth and in close range, it doesn't mean that that was sufficient to initiate an infection," she says. Whether you get sick from that germy onslaught is going to depend on a lot of things — the particular virus, whether the sneeze landed in your mouth or nose, whether you've been exposed to some version of that virus before and more.

One tiny positive side effect of the coronavirus pandemic for Lakdawala has been a broader public understanding of "dose-response" in viral transmission. "Just because somebody breathed on you once doesn't necessarily mean that that's what's going to get you infected," she says.

Consider practicing the swiss cheese model of transmission control, Shu says. "Every layer of protection helps — if you find that wearing a face shield is too much, but you do everything else, you're still going to limit your exposure," she says. Just do what works for you and your family.

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

Reconstructions from the Daynès Studio in Paris depict a male Neanderthal (right) face to face with a human, Homo sapiens.; Credit: /Science Source

It's something that many of us reckon with: the sense that we're not quite as sharp as we once were.

I recently turned 42. Having lost my grandfather to Alzheimer's, and with my mom suffering from a similar neurodegenerative disease, I'm very aware of what pathologies might lurk beneath my cranium.

In the absence of a cure for Alzheimer's and other forms of dementia, the most important interventions for upholding brain function are preventive — those that help maintain our most marvelous, mysterious organ.

Based on the science, I take fish oil and broil salmon. I exercise. I try to challenge my cortex to the unfamiliar.

As I wrote my recent book, A History of the Human Brain, which recounts the evolutionary tale of how our brain got here, I began to realize that so many of the same influences that shaped our brain evolution in the first place reflect the very measures we use to preserve our cognitive function today.

Being social, and highly communicative. Exploring creative pursuits. Eating a varied, omnivorous diet low in processed foods. Being physically active.

These traits and behaviors help retrace our past, and, I believe, were instrumental in why we remain on the planet today.

And they all were, at least in part, enabled by our brain.

Social smart alecks finish first

The human saga is riddled with extinctions.

By "human," I don't just mean Homo sapiens, the species we belong to, but any member of the genus Homo. We've gotten used to being the only human species on Earth, but in our not so distant past — probably a few hundred thousand years ago – there were at least nine of us running around.

There was Homo habilis, or the "handy man." And Homo erectus, the first "pitcher." The Denisovans roamed Asia, while the more well-known Neanderthals spread throughout Europe.

But with the exception of Homo sapiens, they're all gone. And there's a good chance it was our fault.

Humans were never the fastest lot on the African plains, and far from the strongest. Cheetahs, leopards and lions held those distinctions. In our lineage, natural selection instead favored wits and wiliness.

Plenty of us became cat food, but those with a slight cognitive edge — especially Homo sapiens — lived on. In our ilk, smarts overcame strength and speed in enabling survival.

Ecology, climate, location and just sheer luck would've played important roles in who persisted or perished as well, as they do for most living beings. But the evolutionary pressure for more complex mental abilities would lead to a massive expansion in our brain's size and neurocircuitry that is surely the paramount reason we dominate the planet like no other species ever has.

Much of this "success," if you can call it that, was due to our social lives.

Primates are communal creatures. Our close monkey and ape cousins are incredibly interactive, grooming each other for hours a day to maintain bonds and relationships. Throw in a few hoots and hollers and you have a pretty complex community of communicating simians.

An active social life is now a known preserver of brain function.

Research shows that social isolation worsens cognitive decline (not to mention mental health, as many of us experienced this past year). Larger social networks and regular social activities are associated with mental preservation and slowed dementia progression.

Entwined in this new social life was an evolutionary pressure that favored innovation. Our eventual ability to generate completely novel thoughts and ideas, and to share those ideas, came to define our genus.

As we hunted and foraged together, and honed stones into hand axes, there was a collective creativity at work that gave us better weapons and tools that enabled more effective food sourcing, and, later, butchering and fire. Effectively sharing these innovations with our peers allowed information to spread faster than ever before - a seed for the larger communities and civilizations to come.

Challenging ourselves to new pursuits and mastering new skills can not only impress peers and ingratiate us to our group, but literally help preserve our brain. New hobbies. New conversations. Learning the banjo. Even playing certain video games and simply driving a new route home from work each day, as neuroscientist David Eagleman does, can keep our function high.

Whether it's honing ancient stone or taking up Sudoku, any pursuit novel and mentally challenging may help keep the neural circuits firing.

We really are what we eat

All the while, as we hunted and crafted in new and communal ways, we had to eat. And we did so with an uniquely adventurous palette.

Homo sapiens is among the most omnivorous species on the planet. Within reason we eat just about anything. Whether it's leaves, meat, fungus, or fruit, we don't discriminate. At some point, one of us even thought it might be a good idea to try the glistening, grey blobs that are oysters - and shellfish are, it turns out, among the healthiest foods for our brain.

The varied human diet is an integral part of our story. As was the near constant physicality required to source it.

On multiple occasions over the past 1 to 2 million years climate changes dried out the African landscape, forcing our ancestors out of the lush forest onto the dangerous, wide-open grasslands. As evolution pressured us to create and commune to help us survive, a diverse diet also supported our eventual global takeover.

Our arboreal past left us forever craving the dangling fruits of the forest, a supreme source of high-calorie sugars that ensured survival. Back then we didn't live long enough to suffer from Type 2 diabetes: if you encountered sweets, you ate them. And today we're stuck with a taste for cookies and candy that, given our longer lifespans, can take its toll on the body and brain.

But humans were just as amenable to dining on the bulbs, rhizomes and tubers of the savanna, especially once fire came along. We eventually became adept scavengers of meat and marrow, the spoils left behind by the big cats, who preferred more nutritive organ meat.

As our whittling improved we developed spears, and learned to trap and hunt the beasts of the plains ourselves. There is also evidence that we learned to access shellfish beds along the African coast and incorporate brain-healthy seafood into our diet.

Studying the health effects of the modern diet is tricky. Dietary studies are notoriously dubious, and often involve countless lifestyle variables that are hard to untangle.

Take blueberries. Multiple studies have linked their consumption with improved brain health. But, presumably, the berry-prone among us are also more likely to eat healthy all around, exercise, and make it to level 5 on their meditation app.

Which is why so many researchers, nutritionists, and nutritional psychiatrists now focus on dietary patterns, like those akin to Mediterranean culinary customs, rather than specific ingredients. Adhering to a Mediterranean diet is linked with preserved cognition; and multiple randomized-controlled trials suggest doing so can lower depression risk.

A similar diversity in our ancestral diet helped early humans endure an ever-shifting climate and times of scarcity. We evolved to subsist and thrive on a wide range of foods, in part because our clever brains allowed us access to them. In turn, a similarly-varied diet (minus submitting to our innate sugar craving of course) is among the best strategies to maintain brain health.

All of our hunting, and foraging, and running away from predators would have required intense physical exertion. This was certainly not unique to humans, but we can't ignore the fact that regular exercise is another effective means of preserving brain health.

Being active improves performance on mental tasks, and may help us better form memories. Long before the Peletons sold out, our brains relied on both mental and physical activity.

But overwhelmingly the evidence points to embracing a collection of lifestyle factors to keep our brain healthy, none of which existed in a Darwinian vacuum.

Finding food was as social an endeavor as it was mental and physical. Our creative brains harnessed information; gossiping, innovating, and cooking our spoils around the campfire.

Researchers are beginning to piece together the complex pathology behind the inevitable decline of the human brain, and despite a parade of failed clinical trials in dementia, there should be promising treatments ahead.

Until then, in thinking about preserving the conscious experience of our world and relationships — and living our longest, happiest lives — look to our past.

Bret Stetka is a writer based in New York and an editorial director at Medscape. His work has appeared in Wired, Scientific American, and on The Atlantic.com. His new book, A History of the Human Brain, is out from Timber/Workman Press. He's also on Twitter: @BretStetka.

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

The USGS is working with federal land management agencies to develop a series of structured science syntheses (SSS) to support National Environmental Policy Act (NEPA) analyses. This new synthesis is the third publication in the SSS series and provides science to support NEPA analyses for agency decisions regarding oil and gas leasing and permitting.

This summer, USGS Western Fisheries Research Center and collaborating scientists were delighted to find that the abundance of wild born juvenile fall Chinook salmon migrating out of the Snake River has increased by almost 2 orders of magnitude within the last 30 years. 

Western Fisheries Research Center scientists are studying the impacts of increased artificial light at night (ALAN) on aquatic ecosystems.  Here's an overview with recent pictures from the field!

"This is a petty, partisan power grab that is absolutely retaliation towards my office," Arizona Democratic Secretary of State Katie Hobbs says of the new law.; Credit: Ross D. Franklin/AP

Arizona Republicans have stripped the secretary of state's office — currently held by a Democrat — of the right to defend the state's election laws in court, or choose not to, a change enacted as part of Arizona's newly signed budget.

The spending blueprint that Gov. Doug Ducey signed into law Wednesday declares that the attorney general — currently a position occupied by Republican Mark Brnovich — has sole authority over election-related litigation.

If the secretary of state and attorney general were to disagree over a legal strategy when Arizona election laws are challenged, the new law states that "the authority of the attorney general to defend the law is paramount."

Republicans also adopted language stating it's their intent for the law to apply through Jan. 2, 2023, coinciding with the end of Democrat Katie Hobbs' term as secretary of state.

Hobbs, the top election official in Arizona who's now running for governor, says her lawyers are looking at whether this change violates the Arizona Constitution.

"This is a petty, partisan power grab that is absolutely retaliation towards my office," Hobbs said. "It's clear by the fact that it ends when my term ends. ... It is at best legally questionable, but at worst, likely unconstitutional."

Republicans have generally cast the law as a cost-saving measure, citing Hobbs and Brnovich's frequent disagreements over how to defend state election laws that have been challenged in court. In 2020, Hobbs filed complaints with the state bar against Brnovich and other lawyers in his office.

Other election provisions in the budget

The budget includes a number of other election provisions, and it comes weeks after Republicans enacted new restrictions on early voting in the state, and as a controversial review of 2020 election results in Maricopa County continues.

Here are some of the other election-related measures in the budget:

• New laws could soon require watermarks, QR codes and other security measures to be printed on ballots.
• There's a new mandate to inspect state and county voter registration databases and create a report on voters who cast federal-only ballots — an option available to Arizonans who don't show proof of citizenship to register to vote in the state, but are still allowed to register under federal law.
• And a new task force would investigate alleged social media bias as an unreported in-kind political contribution.

The ballot security measures, though not mandated by law in the budget, have the potential to be the most cumbersome and costly requirement for county election officials to implement.

The budget amendment provides a list of 10 "ballot fraud countermeasures" for counties to choose from — features like holographic foil, background designs similar to those found on banknotes and ultraviolet or infrared ink. If mandated, counties would have to implement any combination of at least three features from the list on their ballots. The budget provides $12 million to pay for those features, to be split among Arizona's 15 counties.

"By everyone's admission, there is only one company that can do any of this," said Jennifer Marson, executive director of the Arizona Association of Counties. "And so now, we can't have a competitive bid process or a traditional procurement process at the county or state level to use these countermeasures because we're locked into one company."

That company is Authentix, a Texas-based firm that provided Republican Rep. Mark Finchem with a sample ballot that included watermarks, QR codes and other security measures. Finchem had the sample ballot on display at the Capitol in March. According to the Yellow Sheet Report, it could be five times more expensive to print ballots with those security measures as it is to print paper ballots currently in use.

Marson said Finchem has acknowledged the security levels required of companies in the budget amendment could only be met by Authentix, and has vowed to mandate the ballot security measures in the "very near future."

Finchem defended the company in a brief email. He wrote that Authentix "offers these countermeasures to governments around the world for document and tax stamp security."

As the budget was being considered, Democrats like Sen. Tony Navarrete said the amendment is part of a broad effort to solidify conspiracy theories of election fraud.

"It's important for us to make sure we vote down conspiracy-laced amendments that are going to hurt the integrity of our election system in the state of Arizona and encourage other states to have these bad copycat laws spread like wildfire," he said.

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

A waitress wears a face mask while serving at Langer's Delicatessen-Restaurant in Los Angeles on June 15.; Credit: Frederic J. Brown/AFP via Getty Images

Normal is not easily defined.

The past 15 months, though, have certainly been anything but.

Americans are starting to believe a "sense of normal" is approaching fairly soon, however, according to a new NPR/PBS NewsHour/Marist survey. The poll also found that with the coronavirus receding in this country, mask-wearing is declining and Americans are going out more. But they remain cautious about being in large crowds.

As the country continues to open up, more focus turns to the economy, which cratered during the beginning of the pandemic last year. And Americans are split by race, gender and politics on whether President Biden's ambitious policies are helping or not.

Race, gender, party divides on Biden and the economy

Three months ago, in a similar survey, 49% of adults said the president's policies were strengthening the economy, while 44% said they were weakening it.

Now, that's declined a net of 6 points, as 44% of respondents in the new poll say Biden's policies have strengthened the economy and 45% say the opposite. The percentage who were unsure also jumped 4 points. It's all a little bit of a warning sign for Biden, as he pushes for two large — and expensive — spending packages.

There are significant splits by race and gender:

• Just 39% of whites said Biden's policies have strengthened the economy, but 52% of people of color say they have.
• 54% of independent men say his policies have weakened the economy, while 56% of independent women say they've strengthened it. 
• 45% of white male college grads say Biden has strengthened the economy, but a significantly higher 64% of white women with college degrees said so.

Inflation vs. wages by party

A quarter of Americans rank inflation as the U.S. economy's top concern. That's followed by wages, unemployment, housing costs, labor shortages, gas prices and interest rates.

But there's a sharp political divide on the question. Republicans and independents rank inflation as their top concern, while for Democrats, it was wages. Just 4% of Republicans said wages were their top concern.

Return to "normal"

Americans are growing increasingly optimistic about when life will return to a "sense of normal," as the survey labels it.

In April, three-quarters of Americans said they believe it will take six months or more. Now, it's just half. About a quarter (27%) say it will be less than six months, up from 15% two months ago.

People are also growing more comfortable doing certain things, saying they're:

• dining out at restaurants (78%) and 
• visiting unvaccinated friends and family (75%).

But they are not as comfortable doing others:

• almost 7-in-10 are not going out to bars; 
• about two-thirds are not attending live concerts or sporting events (65%);
• and a majority have also not resumed going to in-person religious services (54%).

COVID-19 vaccines and going back to work

While half say they are concerned about another coronavirus surge, almost 9-in-10 U.S. adults with jobs say they are at least somewhat comfortable returning to work.

Notably, a majority (57%) of those with jobs do not believe employers should require COVID-19 vaccines as a condition to return to in-person work.

More than a quarter of Americans say they will not get vaccinated. The most resistant to getting vaccinated continue to be supporters of former President Donald Trump. Half of them say they won't get the shot, the highest of any group surveyed. Trump has touted the vaccine and got it himself.

Since Centers for Disease Control and Prevention guidelines came out, noting that Americans who have been vaccinated can largely set masks aside, there's been a double-digit decline in those saying they wear a mask even when it's not required.

There's also been a double-digit increase in those saying they generally do not wear a mask. In May, 49% said they wore masks even when it was not required. Now, that's just 36%.

One-in-five said they generally do not wear masks. Two months ago, it was less than one-in-10.

Affordability, not coronavirus, limiting vacations

Speaking of getting back to normal, a majority of Americans say they plan to take a vacation this summer.

But of the significant minority (45%) who say they aren't taking one, almost three times as many cited affordability (35%) as the main reason for not going, as opposed to concerns about COVID-19 (12%).

Methodology: The poll of 1,115 U.S. adults was conducted using live telephone interviewers from June 22 through June 29. Survey questions were available in English or Spanish. The full sample has a margin of error of plus or minus 3.7 percentage points, with larger margins of error for smaller group subsets.

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