With the growing interest in scale-resolving simulations of spatially evolving boundary layers, synthetic turbulence generation (STG) has become a valuable tool for providing unsteady turbulent boundary conditions through a sum over a finite number of spatio-temporal Fourier modes with amplitude, direction and phase determined by a random number set. Recent developments of STG methods are designed to match target profiles for anisotropic and inhomogeneous Reynolds stresses. In this paper, it is shown that, for practical values of the number of modes, a given set of random numbers may produce Reynolds stress profiles that are 30 % off their target. To remedy this situation, the error in the STG stress prediction is decomposed into a steady-state bias and a purely unsteady part affecting the time convergence. Direct relationships between the random number vectors and both types of error are developed, allowing large collections of random number sets to be rapidly scanned and the best performers selected for a much improved agreement with the target. The process is verified for the inflow to a direct numerical simulation of a flat plate at $Re_\theta = 1000$. This paper demonstrates sufficient time convergence over a few flow-through times as well as a correction of the method's biases.

This article reviews the advancements and prospects of liquid cell transmission electron microscopy (TEM) imaging and analysis methods in understanding the nucleation, growth, etching, and assembly dynamics of nanocrystals. The bonding of atoms into nanoscale crystallites produces materials with nonadditive properties unique to their size and geometry. The recent application of in situ liquid cell TEM to nanocrystal development has initiated a paradigm shift, (1) from trial-and-error synthesis to a mechanistic understanding of the “synthetic reactions” responsible for the emergence of crystallites from a disordered soup of reactive species (e.g., ions, atoms, molecules) and shape-defined growth or etching; and (2) from post-processing characterization of the nanocrystals’ superlattice assemblies to in situ imaging and mapping of the fundamental interactions and energy landscape governing their collective phase behaviors. Imaging nanocrystal formation and assembly processes on the single-particle level in solution immediately impacts many existing fields, including materials science, nanochemistry, colloidal science, biology, environmental science, electrochemistry, mineralization, soft condensed-matter physics, and device fabrication.

Insights into the dynamics of electrochemical processes are critically needed to improve our fundamental understanding of electron, charge, and mass transfer mechanisms and reaction kinetics that influence a broad range of applications, from the functionality of electrical energy-storage and conversion devices (e.g., batteries, fuel cells, and supercapacitors), to materials degradation issues (e.g., corrosion and oxidation), and materials synthesis (e.g., electrodeposition). To unravel these processes, in situ electrochemical scanning/transmission electron microscopy (ec-S/TEM) was developed to permit detailed site-specific characterization of evolving electrochemical processes that occur at electrode–electrolyte interfaces in their native electrolyte environment, in real time and at high-spatial resolution. This approach utilizes “closed-form” microfabricated electrochemical cells that couple the capability for quantitative electrochemical measurements with high spatial and temporal resolution imaging, spectroscopy, and diffraction. In this article, we review the state-of-the-art instrumentation for in situ ec-S/TEM and how this approach has resulted in new observations of electrochemical processes.

This article addresses recent advances in liquid phase transmission electron microscopy (LPTEM) for studying nanoscale synthetic processes of carbon-based materials that are independent of the electron beam—those driven by nonradiolytic chemical or thermal reactions. In particular, we focus on chemical/physical formations and the assembly of nanostructures composed of organic monomers/polymers, peptides/DNA, and biominerals. The synthesis of carbon-based nanomaterials generally only occurs at specific conditions, which cannot be mimicked by aqueous solution radiolysis. Carbon-based structures themselves are also acutely sensitive to the damaging effects of the irradiating beam, which make studying their synthesis using LPTEM a unique challenge that is possible when beam effects can be quantified and mitigated. With new direct sensing, high frame-rate cameras, and advances in liquid cell holder designs, combined with a growing understanding of irradiation effects and proper experimental controls, microscopists have been able to make strides in observing traditionally problematic carbon-based materials under conditions where synthesis can be controlled, and imaged free from beam effects, or with beam effects quantified and accounted for. These materials systems and LPTEM experimental techniques are discussed, focusing on nonradiolytic chemical and physical transformations relevant to materials synthesis.

The Coneybury ‘Anomaly’ is an Early Neolithic pit located just south-east of Stonehenge, Wiltshire. Excavations recovered a faunal assemblage unique in its composition, consisting of both wild and domestic species, as well as large quantities of ceramics and stone tools, including a substantial proportion of blades/bladelets. We present a suite of new isotope analyses of the faunal material, together with ancient DNA sex determination, and reconsider the published faunal data to ask: What took place at Coneybury, and who was involved? We argue on the basis of multiple lines of evidence that Coneybury represents the material remains of a gathering organised by a regional community, with participants coming from different areas. One group of attendees provided deer instead of, or in addition to, cattle. We conclude that the most likely scenario is that this group comprised local hunter-gatherers who survived alongside local farmers.

The island of Bonaire is a long-established Marine Protected Area (MPA), the reefs of which were extensively mapped in the early 1980s. Satellite remote sensing techniques were used to construct reef maps for 2008–2009. Metrics describing the spatial structure of coral habitat at the landscape scale – including coral cover, fragmentation, patch size and connectivity between patches – were calculated and compared between these two time periods. Changes were evaluated in and out of the MPAs and in areas exposed and sheltered from storm damage. Overall, coral cover has declined during the past three decades, being replaced by sand, but the decline has not been as drastic as elsewhere in the Caribbean. Fragmentation of the reef habitat has occurred, resulting in smaller and more disparate patches, but these changes were not associated with exposure along the coastline. However, total coral cover was maintained in sheltered areas, whereas it declined along exposed shorelines. Human protection of reefs by marine reserves had variable effects on coral cover and fragmentation. One of two no-diving marine reserves showed increases in coral cover accompanied by decreases in the number of patches of coral and an increase in the size of individual patches over the time period, while the second reserve exhibited the opposite trend. Advances in satellite remote sensing techniques allow for a more rapid assessment of changes in reefs at the landscape level, which can be used to identify spatial changes in the reef environment, including areas of coral decline.

Vitamin D deficiency is a common occurrence globally, and particularly so in pregnancy. There is conflicting evidence regarding the role of vitamin D during pregnancy in non-skeletal health outcomes for both the mother and the neonate. The aim of this study was to investigate the associations of maternal total 25-hydroxy vitamin D (25OHD) with neonatal anthropometrics and markers of neonatal glycaemia in the Belfast centre of the Hyperglycemia and Adverse Pregnancy Outcome (HAPO) study. Serological samples (n 1585) were obtained from pregnant women in the Royal Jubilee Maternity Hospital, Belfast, Northern Ireland, between 24 and 32 weeks’ gestation as part of the HAPO study. 25OHD concentrations were measured by liquid chromatography tandem-MS. Cord blood and neonatal anthropometric measurements were obtained within 72 h of birth. Statistical analysis was performed. After adjustment for confounders, birth weight standard deviation scores (SDS) and birth length SDS were significantly associated with maternal total 25OHD. A doubling of maternal 25OHD at 28 weeks’ gestation was associated with mean birth weight SDS and mean birth length SDS higher by 0·05 and 0·07, respectively (both, P=0·03). There were no significant associations with maternal 25OHD and other measures of neonatal anthropometrics or markers of neonatal glycaemia. In conclusion, maternal total 25OHD during pregnancy was independently associated with several neonatal anthropometric measurements; however, this association was relatively weak.