In situ elemental imaging of planetary surface regolith at a spatial resolution of 100s to 1000s of microns can provide evidence of the provenance of rocks or sediments and their habitability, and can identify post-depositional diagenetic alteration affecting preservation. We use high-resolution elemental maps and XRF spectra from MapX, a flight prototype in situ X-ray imaging instrument, to demonstrate this technology in rock types relevant to astrobiology. Examples are given for various petrologies and depositional/diagenetic environments, including ultramafic/mafic rocks, serpentinites, hydrothermal carbonates, evaporites, stromatolitic cherts and diagenetic concretions.

Helium or neopentane can be used as surrogate gas fill for deuterium (D2) or deuterium-tritium (DT) in laser-plasma interaction studies. Surrogates are convenient to avoid flammability hazards or the integration of cryogenics in an experiment. To test the degree of equivalency between deuterium and helium, experiments were conducted in the Pecos target chamber at Sandia National Laboratories. Observables such as laser propagation and signatures of laser-plasma instabilities (LPI) were recorded for multiple laser and target configurations. It was found that some observables can differ significantly despite the apparent similarity of the gases with respect to molecular charge and weight. While a qualitative behaviour of the interaction may very well be studied by finding a suitable compromise of laser absorption, electron density, and LPI cross sections, a quantitative investigation of expected values for deuterium fills at high laser intensities is not likely to succeed with surrogate gases.

This work investigates the effect of surface roughness on cylinder flows in the postcritical regime and reexamines whether the roughness Reynolds number ($Re_{k_s}$) primarily governs the aerodynamic behaviour. It has been motivated by limitations of many previous investigations, containing occasionally contradictory findings. In particular, many past studies were conducted with relatively high blockage ratios and low cylinder aspect ratios. Both of these factors appear to have non-negligible effects on flow behaviour, and particularly fluctuating quantities such as the standard deviation of the lift coefficient. This study employs a 5 % blockage ratio and a span-to-diameter ratio of 10. Cylinders of different relative surface roughness ratios ($k_s/D$), ranging from $1.1\times 10^{-3}$ to $3\times 10^{-3}$, were investigated at Reynolds numbers up to $6.8 \times 10^5$ and $Re_{k_s}$ up to 2200. It is found that the base pressure coefficient, drag coefficient, Strouhal number, spanwise correlation length of lift and the standard deviation of the lift coefficient are well described by $Re_{k_s}$ in postcritical flows. However, roughness does have an effect on the minimum surface pressure coefficient (near separation) that does not collapse with $Re_{k_s}$. The universal Strouhal number proposed by Bearman (Annu. Rev. Fluid Mech., vol. 16, 1984, pp. 195–222) appears to be nearly constant over the range of $Re_{k_s}$ studied, spanning the subcritical through postcritical regimes. Frequencies in the separating shear layers are found to be an order of magnitude lower than the power law predictions for separating shear layers of smooth cylinders.

We compared the effectiveness of 4 sampling methods to recover Staphylococcus aureus, Klebsiella pneumoniae and Clostridioides difficile from contaminated environmental surfaces: cotton swabs, RODAC culture plates, sponge sticks with manual agitation, and sponge sticks with a stomacher. Organism type was the most important factor in bacterial recovery.

Seabirds are highly threatened, including by fisheries bycatch. Accurate understanding of offshore distribution of seabirds is crucial to address this threat. Tracking technologies revolutionised insights into seabird distributions but tracking data may contain a variety of biases. We tracked two threatened seabirds (Salvin’s Albatross Thalassarche salvini n = 60 and Black Petrel Procellaria parkinsoni n = 46) from their breeding colonies in Aotearoa (New Zealand) to their non-breeding grounds in South America, including Peru, while simultaneously completing seven surveys in Peruvian waters. We then used species distribution models to predict occurrence and distribution using either data source alone, and both data sources combined. Results showed seasonal differences between estimates of occurrence and distribution when using data sources independently. Combining data resulted in more balanced insights into occurrence and distributions, and reduced uncertainty. Most notably, both species were predicted to occur in Peruvian waters during all four annual quarters: the northern Humboldt upwelling system for Salvin’s Albatross and northern continental shelf waters for Black Petrels. Our results highlighted that relying on a single data source may introduce biases into distribution estimates. Our tracking data might have contained ontological and/or colony-related biases (e.g. only breeding adults from one colony were tracked), while our survey data might have contained spatiotemporal biases (e.g. surveys were limited to waters <200 nm from the coast). We recommend combining data sources wherever possible to refine predictions of species distributions, which ultimately will improve fisheries bycatch management through better spatiotemporal understanding of risks.

This paper demonstrates experimentally that imposed periodic forcing can significantly alter the global flow characteristics of the flow over a double backward-facing step. The geometry consists of two equal height steps spaced up to eight step heights apart. A periodic zero-mass flux jet located at the first step's top corner was issued at frequencies ranging from below the step-mode instability frequency up to approximately five times the shear-layer instability frequency. Reattachment of the flow onto the first step was achieved for step separations as low as three single-step heights with imposed forcing; significantly shorter than the five single-step heights that occurred without forcing. A significant reduction in mean base pressure on the first step, and increase on the second step, occurred for low forcing frequencies. Even for large step separations, the effect of forcing on the flow persisted sufficiently far downstream to appreciably influence the development of the second recirculation zone. Importantly, previous forced single and unforced double backward-facing step flows provide reference cases to examine and discuss similarities and differences. This study offers insight into possibilities and potential outcomes of flow control for applications ranging from the drag reduction of ground vehicles such as pickup trucks, to enhanced mixing in industrial processes.

This article contends that Brazil's evangelical Christian networks increasingly function as penal infrastructure. Since the 1990s, the scale and scope of evangelical involvement in the criminal justice system have grown significantly. One clear result is that the capillary relationships that constitute Christian community now mobilise resources to support or even substitute the basic functions of punishment. I draw on fieldwork in Rio de Janeiro to understand this shift and its broader implications for the Brazilian project of incarceration. I also make a general claim for thinking with and through infrastructure as a pathway to understand penal governance.

The backward-facing step is perhaps the quintessential geometry used to study separated flow. Extensive previous research has quantified its detailed flow characteristics. However, often regions of separated flow do not exist in isolation; rather, interaction occurs between multiple regions. This motivated an experimental investigation into the time-averaged and dynamic flow features of a double backward-facing step, covering separations of zero to eight step heights between equal-height steps. Three flow regimes are identified. A single reattachment regime occurs for separations of less than four step heights, perhaps remarkable for the lack of variation in key flow characteristics from a single backward-facing step response. Next, an intermediate regime is identified for a separation of four step heights. In this case, the flow does not yet reattach on the first step, although significant differences in reattachment length, surface pressure on the vertical step faces and turbulence statistics occur. Finally, for greater step separations, a double reattachment regime, with reattachment on both steps, is identified. Downwash, induced by the first recirculation zone, reduces the reattachment length and turbulent fluctuations of the second recirculation zone. The surface pressure on the first-step vertical face is reduced, seemingly a result of an upstream influence due to the low pressure in the second-step recirculation zone. Detailed characterisation of the regimes offers insight into the fundamental interaction of regions of separated flow, revealing aspects of complex dynamics relevant to a broad range of practical scenarios.

The fossil record is notoriously imperfect and biased in representation, hindering our ability to place fossil specimens into an evolutionary context. For groups with fossil records mostly consisting of disarticulated parts (e.g., vertebrates, echinoderms, plants), the limited morphological information preserved sparks concerns about whether fossils retain reliable evidence of phylogenetic relationships and lends uncertainty to analyses of diversification, paleobiogeography, and biostratigraphy in Earth's history. To address whether a fragmentary past can be trusted, we need to assess whether incompleteness affects the quality of phylogenetic information contained in fossil data. Herein, we characterize skeletal incompleteness bias in a large dataset (6585 specimens; 14,417 skeletal elements) of fossil squamates (lizards, snakes, amphisbaenians, and mosasaurs). We show that jaws + palatal bones, vertebrae, and ribs appear more frequently in the fossil record than other parts of the skeleton. This incomplete anatomical representation in the fossil record is biased against regions of the skeleton that contain the majority of morphological phylogenetic characters used to assess squamate evolutionary relationships. Despite this bias, parsimony- and model-based comparative analyses indicate that the most frequently occurring parts of the skeleton in the fossil record retain similar levels of phylogenetic signal as parts of the skeleton that are rarer. These results demonstrate that the biased squamate fossil record contains reliable phylogenetic information and support our ability to place incomplete fossils in the tree of life.

Rock debris covers ~30% of glacier ablation areas in the Central Himalaya and modifies the impact of atmospheric conditions on mass balance. The thermal properties of supraglacial debris are diurnally variable but remain poorly constrained for monsoon-influenced glaciers over the timescale of the ablation season. We measured vertical debris profile temperatures at 12 sites on four glaciers in the Everest region with debris thickness ranging from 0.08 to 2.8 m. Typically, the length of the ice ablation season beneath supraglacial debris was 160 days (15 May to 22 October)—a month longer than the monsoon season. Debris temperature gradients were approximately linear (r2 > 0.83), measured as −40°C m–1 where debris was up to 0.1 m thick, −20°C m–1 for debris 0.1–0.5 m thick, and −4°C m–1 for debris greater than 0.5 m thick. Our results demonstrate that the influence of supraglacial debris on the temperature of the underlying ice surface, and therefore melt, is stable at a seasonal timescale and can be estimated from near-surface temperature. These results have the potential to greatly improve the representation of ablation in calculations of debris-covered glacier mass balance and projections of their response to climate change.

Immunocompromised patients are at risk for infections due to above-ceiling activities in hospitals. Mobile dust-containment carts are available as environmental controls, but no published data support their efficacy. Using microbial air sampling and particle counts, we provide evidence of reduced risk of fungal exposure during open ceiling activities.