A method for extracting Ni and other metals from lateritic ores by means of shock heating has been investigated. Shock heating releases some of the metal from its goethitic host. Even though the transformation of pure goethite to hematite is known to occur via intermediate hydroxylated phases, the effect of other metals such as Ni substituting for Fe in goethites on this thermal transformation to hematite is unknown. The purpose of this study was to fill this gap, with the hope that the results will lead to more energy-efficient extraction methods and/or a better understanding of Fe geochemistry in thermally activated soils. X-ray diffraction, transmission electron microscopy with EDS, and thermal analysis were used to investigate mineralogical changes in nickeliferous goethites from five oxide-type lateritic nickel ore deposits that had been subjected to shock heating at temperatures in the range 220–800°C. Acicular, nano-sized goethite was the main constituent of the samples with minor to trace amounts of quartz, talc, kaolinite, chromite, maghemite, and Mn oxides. Goethite was partially dehydroxylated to OH-hematite at 340–400°C and had completely altered to well ordered hematite at 800°C. The OH-hematite was characterized by broad XRD peaks for reflections associated with the Fe sublattice. The goethite unit-cell a and b lengths remained almost constant with increasing preheating temperature up to 300°C, while the size of the c axis dimension contracted. The neoformed hematite crystals were larger than the precursor goethite crystals due to development, by sintering and surface diffusion, of regularly ordered hematite domains. The increase (1.5–2.6 fold) in surface area with increasing heating temperature (up to 340–400°C) reflected the development of slit-shaped micropores (∼300°C), which further developed into elliptically shaped micropores (∼400°C) in OH-hematite. With increased heating temperature, well ordered hematite formed with only a few micropores remaining. Such results may contribute to the development of more efficient procedures for extracting Ni from lateritic nickel ores, as the rate of dissolution of goethite in acid in ‘heap and pressure’ leach facilities will be enhanced by the increases in surface area and microporosity. The results may also provide valuable information on the probable effects of natural heating on pedogenic Fe oxides.

We recently reported on the radio-frequency attenuation length of cold polar ice at Summit Station, Greenland, based on bi-static radar measurements of radio-frequency bedrock echo strengths taken during the summer of 2021. Those data also allow studies of (a) the relative contributions of coherent (such as discrete internal conducting layers with sub-centimeter transverse scale) vs incoherent (e.g. bulk volumetric) scattering, (b) the magnitude of internal layer reflection coefficients, (c) limits on signal propagation velocity asymmetries (‘birefringence’) and (d) limits on signal dispersion in-ice over a bandwidth of ~100 MHz. We find that (1) attenuation lengths approach 1 km in our band, (2) after averaging 10 000 echo triggers, reflected signals observable over the thermal floor (to depths of ~1500 m) are consistent with being entirely coherent, (3) internal layer reflectivities are ≈–60$\to$–70 dB, (4) birefringent effects for vertically propagating signals are smaller by an order of magnitude relative to South Pole and (5) within our experimental limits, glacial ice is non-dispersive over the frequency band relevant for neutrino detection experiments.

HIV and severe wasting are associated with post-discharge mortality and hospital readmission among children with complicated severe acute malnutrition (SAM); however, the reasons remain unclear. We assessed body composition at hospital discharge, stratified by HIV and oedema status, in a cohort of children with complicated SAM in three hospitals in Zambia and Zimbabwe. We measured skinfold thicknesses and bioelectrical impedance analysis (BIA) to investigate whether fat and lean mass were independent predictors of time to death or readmission. Cox proportional hazards models were used to estimate the association between death/readmission and discharge body composition. Mixed effects models were fitted to compare longitudinal changes in body composition over 1 year. At discharge, 284 and 546 children had complete BIA and skinfold measurements, respectively. Low discharge lean and peripheral fat mass were independently associated with death/hospital readmission. Each unit Z-score increase in impedance index and triceps skinfolds was associated with 48 % (adjusted hazard ratio 0·52, 95 % CI (0·30, 0·90)) and 17 % (adjusted hazard ratio 0·83, 95 % CI (0·71, 0·96)) lower hazard of death/readmission, respectively. HIV-positive v. HIV-negative children had lower gains in sum of skinfolds (mean difference −1·49, 95 % CI (−2·01, −0·97)) and impedance index Z-scores (–0·13, 95 % CI (−0·24, −0·01)) over 52 weeks. Children with non-oedematous v. oedematous SAM had lower mean changes in the sum of skinfolds (–1·47, 95 % CI (−1·97, −0·97)) and impedance index Z-scores (–0·23, 95 % CI (−0·36, −0·09)). Risk stratification to identify children at risk for mortality or readmission, and interventions to increase lean and peripheral fat mass, should be considered in the post-discharge care of these children.

Functional benefits of the morphologies described by Bergmann's and Allen's rules in human males have recently been reported. However, the functional implications of ecogeographical patterning in females remain poorly understood. Here, we report the findings of preliminary work analysing the association between body shape and performance in female ultramarathon runners (n = 36) competing in hot and cold environments. The body shapes differed between finishers of hot and cold races, and also between hot race finishers and non-finishers. Variability in race performance across different settings supports the notion that human phenotype is adapted to different thermal environments as ecogeographical patterns have reported previously. This report provides support for the recent hypothesis that the heightened thermal strain associated with prolonged physical activity in hot/cold environments may have driven the emergence of thermally adaptive phenotypes in our evolutionary past. These results also tentatively suggest that the relationship between morphology and performance may be stronger in female vs. male athletes. This potential sex difference is discussed with reference to the evolved unique energetic context of human female reproduction. Further work, with a larger sample size, is required to investigate the observed potential sex differences in the strength of the relationship between phenotype and performance.

Both extinct and extant hominin populations display morphological features consistent with Bergmann's and Allen's Rules. However, the functional implications of the morphologies described by these ecological laws are poorly understood. We examined this through the lens of endurance running. Previous research concerning endurance running has focused on locomotor energetic economy. We considered a less-studied dimension of functionality, thermoregulation. The performance of male ultra-marathon runners (n = 88) competing in hot and cold environments was analysed with reference to expected thermoregulatory energy costs and the optimal morphologies predicted by Bergmann's and Allen's Rules. Ecogeographical patterning supporting both principles was observed in thermally challenging environments. Finishers of hot-condition events had significantly longer legs than finishers of cold-condition events. Furthermore, hot-condition finishers had significantly longer legs than those failing to complete hot-condition events. A degree of niche-picking was evident; athletes may have tailored their event entry choices in accordance with their previous race experiences. We propose that the interaction between prolonged physical exertion and hot or cold climates may induce powerful selective pressures driving morphological adaptation. The resulting phenotypes reduce thermoregulatory energetic expenditure, allowing diversion of energy to other functional outcomes such as faster running.

Digital literacy has been cited as one of the primary challenges to ensuring data reuse and increasing the value placed on open science. Incorporating published data into classrooms and training is at the core of tackling this issue. This article presents case studies in teaching with different published data platforms, in three different countries (the Netherlands, Canada, and the United States), to students at different levels and with differing skill levels. In outlining their approaches, successes, and failures in teaching with open data, it is argued that collaboration with data publishers is critical to improving data reuse and education. Moreover, increased opportunities for digital skills training and scaffolding across program curriculum are necessary for managing the learning curve and teaching students the values of open science.

The ‘Digital Index of North American Archaeology’ (DINAA) project demonstrates how the aggregation and publication of government-held archaeological data can help to document human activity over millennia and at a continental scale. These data can provide a valuable link between specific categories of information available from publications, museum collections and online databases. Integration improves the discovery and retrieval of records of archaeological research currently held by multiple institutions within different information systems. It also aids in the preservation of those data and makes efforts to archive these research results more resilient to political turmoil. While DINAA focuses on North America, its methods have global applicability.

Horsenettle is a deep-rooted perennial weed that cannot be easily controlled by mechanical means or by a single chemical application. A study was conducted at two sites for two consecutive years to identify biological factors that might limit its growth. Insects, nematodes, and plant pathogens were collected from horsenettle growing in bermudagrass pastures. The insects most commonly found included the Colorado potato beetle and the eggplant flea beetle. An unidentified lepidopteron, family Gelechiidae, was found at very low frequency as pupae in hollow leaf chambers constructed at the apices of flowering meristems. Infested apices bore no fruit. Seven genera of nematodes were found in the soil at both sites, but only very low numbers of lesion nematodes were recovered from horsenettle roots, and these had caused little damage. Root rot was observed under wet soil conditions on plants damaged by trampling. A downy mildew was prevalent at both sites in both years in October.

The effects of bristly starbur interference with peanuts were studied from 1980 through 1983 on a Dothan sandy loam (Plinthic Paleudults). Peanut seed yields, which included kernels plus hulls, were reduced as bristly starbur densities increased from 2 to 64 plants/7.5 m of row. Full-season interference from 8, 16, 32, and 64 bristly starbur plants/7.5 m of row reduced peanut seed yields 14, 26, 43, and 50%, respectively. The seed yield of peanuts maintained weed free for 6 weeks after crop emergence was reduced by no more than 3% compared to peanuts maintained weed free for the entire season. Weed interference for 2 weeks after crop emergence reduced seed yield by an average of 4% over the 3-yr period, based on prediction equations. Bristly starbur interference for 13 weeks after crop emergence reduced peanut forage dry weight yield by 54%. Similarly, peanut interference for 13 weeks after emergence reduced bristly starbur forage dry weight yield by 32%. Bristly starbur density in the forage dry weight studies averaged 35/7.5 m of row. These bristly starbur were confined to a 35-cm band over the drill. Peanut density averaged 72/7.5 m of drill.

Four soil chronosequences in the southern Great Basin were examined in order to study and quantify soil development during the Quaternary. Soils of all four areas are developed in gravelly alluvial fans in semiarid climates with 8 to 40 cm mean annual precipitation. Lithologies of alluvium are granite-gneiss at Silver Lake, granite and basalt at Cima Volcanic Field, limestone at Kyle Canyon, and siliceous volcanic rocks at Fortymile Wash. Ages of the soils are approximated from several radiometric and experimental techniques, and rates are assessed using a conservative mathematical approach. Average rates for Holocene soils at Silver Lake are about 10 times higher than for Pleistocene soils at Kyle Canyon and Fortymile Wash, based on limited age control. Holocene soils in all four areas appear to develop at similar rates, and Pleistocene soils at Kyle Canyon and Fortymile Wash may differ by only a factor of 2 to 4. Over time spans of several millennia, a preferred model for the age curves is not linear but may be exponential or parabolic, in which rates decrease with increasing age. These preliminary results imply that the geographical variation in rates within the southern Great Basin-Mojave region may be much less significant than temporal variation in rates of soil development. The reasons for temporal variation in rates and processes of soil development are complexly linked to climatic change and related changes in water and dust, erosional history, and internally driven chemical and physical processes.