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In recent years, the sediment compartment has gained more attention when performing toxicity tests, with a growing emphasis on gaining more ecological relevance in testing. Though many standard guidelines recommend using artificially formulated sediment, most sediment studies are using natural sediment collected in the field. Although the use of natural field‐collected sediment contributes to more environmentally realistic exposure scenarios and higher well‐being for sediment‐dwelling organisms, it lowers comparability and reproducibility among studies as a result of, for example, differences in the base sediment depending on sampling site, background contamination, particle size distribution, or organic matter content. The aim of this methodology contribution is to present and discuss best practices related to collecting, handling, describing, and applying natural field‐collected sediment in ecotoxicological testing. We propose six recommendations: (1) natural sediment should be collected at a well‐studied site, historically and by laboratory analysis; (2) larger quantities of sediment should be collected and stored prior to initiation of an experiment to ensure a uniform sediment base; (3) any sediment used in ecotoxicological testing should be characterized, at the very least, for its water content, organic matter content, pH, and particle size distribution; (4) select spiking method, equilibration time, and experimental setup based on the properties of the contaminant and the research question; (5) include control‐, treated similarly to the spiked sediment, and solvent control sediment when appropriate; and (6) quantify experimental exposure concentrations in the overlying water, porewater (if applicable), and bulk sediment at least at the beginning and the end of each experiment. Environ Toxicol Chem 2024;43:1757–1766. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. [ABSTRACT FROM AUTHOR]

An innovative design methodology is presented to simplify the architecture of outphasing power amplifier (PA). The proposed design, by absorbing transistor parasitic capacitance into reactance compensating network intrinsic for a Chireix outphasing amplifier, greatly reduces the complexity of impedance modulation network at the output side, hence reducing the overall circuit size. Theoretical formulations regarding the introduced design technique are fully described and the effectiveness is verified through the implementation of a 2.6‐GHz PA prototype intended for long term evolution application. The realized circuit achieves maximum power of 44.8 dBm based on two 10‐W gallium nitride (GaN) high electron mobility transistor (HEMTs), accompanying maximum 73.3% drain efficiency between the saturation point and 6‐dB output back‐off point. At the 6‐dB output back‐off point, the drain efficiency reaches 63.5%. [ABSTRACT FROM AUTHOR]

A new instrument for high-resolution optical logging has been built and tested in Antarctica. Its purpose is to obtain records of volcanic products and other scattering features, such as bubbles and impurities, preserved in polar ice sheets, and it achieves this by using long wavelength near-infrared light that is absorbed by the ice before many scattering events occur. Longer wavelengths ensure that the return signal is composed primarily of a single or few backscattering event(s) that limit its spatial spread. The compact optical logger features no components on its body that draw power, which minimizes its size and weight. A prototype of the logger was built and tested at Siple Dome A borehole, and the results were correlated with prior optical logging profiles and records of volcanic products from collected ice core samples. [ABSTRACT FROM AUTHOR]

A method has been devised and tested for measuring the c-axis orientation of crystal grains in thin sections of glacier ice. The crystal orientation and grain size of ice are of great interest to glaciologists since these parameters contain information on the prior thermal and flow history of the ice. The traditional method of determining c-axis orientation involves a transmission measurement through an ice sample, a process that is time-consuming and therefore impractical for obtaining a continuous record. A reflection- or backscatter-based method could potentially be used inside boreholes, with bubbles as reflectors to avoid such drawbacks. The concept demonstration of this paper is performed on ice slices, enabling a direct comparison of accuracy with traditional methods. Measurements of the crystal orientations (φ, θ) in 11 grains showed an average error of ±0.8° in φ, with no grain error >1.4°. Measurements of θ showed an average error of ±8.2° on ten grains, with unexplained disagreement on the remaining grain. Although the technique is applied specifically to glacier ice, it should be generally applicable to any transparent birefringent polycrystalline material. [ABSTRACT FROM AUTHOR]