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Nature Geoscience, Published online: 27 January 2025; doi:10.1038/s41561-024-01637-5

Fire emissions in the Amazon and Cerrado biomes are mainly produced from smouldering combustion of woody debris, according to observationally constrained fire emissions inventories.

Nature Geoscience, Published online: 24 January 2025; doi:10.1038/s41561-025-01640-4

The cause of episodes of unrest at caldera volcanoes is often unclear. Analysis of the sulfur composition of gas emissions at Campi Flegrei in Italy suggests a magmatic origin of the recent unrest at this hazardous caldera.

Nature Geoscience, Published online: 24 January 2025; doi:10.1038/s41561-024-01631-x

Biofilms on the surface of outdoor stone heritage contribute to either biodeterioration or bioprotection. We suggest that halting biofilm activity by limiting biologically available water shifts geomicrobiological development towards bioprotection.

Nature Geoscience, Published online: 24 January 2025; doi:10.1038/s41561-024-01632-w

The recent increase in isotopically light sulfur emissions from Campi Flegrei (Italy) is probably the result of degassing magma at ≥6 km depth and could be an indicator of caldera reawakening generally, according to observations and simulations.

Nature Geoscience, Published online: 24 January 2025; doi:10.1038/s41561-025-01638-y

Plant litter-derived mineral-associated organic matter that formed in the first year and pyrogenic organic inputs both persist on a decadal scale in grassland soil via distinct mechanisms, according to a soil organic matter decomposition experiment.

Gravitationally induced deformation of the receiving unit of radio telescopes used for Very Long Baseline Interferometry (VLBI) distorts the observations and biases the deduced products. As this deformation ac...

Abstract

Spoofing detection is an essential process in global navigation satellite system anti-spoofing. Signal quality monitoring (SQM) methods have been widely studied as simple and effective means to detect spoofing. However, the disadvantages of the existing SQM methods, such as long alarm times and low detection rates, necessitate the study of new methods. Therefore, to address these challenges, this paper proposes a novel SQM method based on a long short-term memory-detect (LSTM-Detect) model with a strong capacity for sequential signal processing. In particular, this method evaluates the distortion of the autocorrelation function (ACF) by the trained LSTM-Detect model for spoofing detection. The simulation results demonstrate that the LSTM-Detect model can detect a wide range of spoofing signals, varying in signal power advantages, code phase differences, and carrier phase differences. In the Texas Spoofing Test Battery datasets 2–6, the detection rate exceeds 98.5%, with an alarm time of less than 5 ms. Compared with five existing SQM methods, the LSTM-Detect model exhibits a more comprehensive spoofing detection performance.

Abstract

Low-cost (LC) Global Navigation Satellite System (GNSS) receivers are argued as an alternative solution to geodetic GNSS counterparts for different applications. Single-frequency low-cost (SF-LC) GNSS receivers have been in the market for many years while their inability to acquire GNSS observations in second frequency limited their use. A few years ago, dual-frequency low-cost (DF-LC) GNSS receivers with enhanced capabilities entered the mass market, considering the advancements they have been tested and evaluated by many researchers. Lastly, multi-frequency low-cost (MF-LC) GNSS receivers become available. With the ability to track more satellite signals, these GNSS receivers are expected to obtain better overall performance. This review article aims to analyze recent advances and applications of LC GNSS receivers. To provide answers to the research question relevant articles were selected and analyzed. From the reviewed articles, it was concluded that the performance of SF-LC and DF-LC GNSS receivers is comparable to that of geodetic counterparts only in open-sky conditions. However, in adverse conditions, the differences become more highlighted. In such environments, SF and DF-LC GNSS receivers face challenges not only with positioning quality but also with their proper work. Limited studies on MF-LC receivers have reported comparable observations and positioning performance to geodetic GNSS receivers. Despite drawbacks, LC GNSS receivers have been successfully applied in surveying, mapping, geodetic monitoring, precision agriculture, navigation, atmosphere monitoring, Earth surface monitoring, and other fields.

Nature Geoscience, Published online: 23 January 2025; doi:10.1038/s41561-024-01635-7

Coral bleaching and mortality are substantially overestimated in most model projections that are based on Degree Heating Months instead of Degree Heating Weeks, calling into question results generated using Degree Heating Months.

Nature Geoscience, Published online: 23 January 2025; doi:10.1038/s41561-024-01630-y

Upper-crustal magma bodies are present beneath most Cascade Range volcanoes, indicating that large volumes of melt can persist at shallow depth through eruption cycles, according to systematic seismic imaging.

We have developed two novel axial anisotropic inversion codes for magnetotelluric (MT) data: a full axial inversion and a decoupled axial inversion. Both codes are based on the data space Gauss–Newton inversio...

The Vrancea Seismic Zone (VSZ) is an atypical intermediate-depth earthquake nest located in the South-East Carpathians in Romania, often regarded as a relic slab sinking into the mantle. The origin of the slab...

Abstract

The process of forming edge metallization on input windows (germanium, silicon, and other discs) used for introducing the received light flux into a photodetector housed in a protective hermetic casing is being investigated. This work presents the results of an experimental study on the dependence of the edge metallization profile of Ge discs, formed by magnetron sputtering, on the design parameters of the loading device. Various designs of loading devices are presented. The experimental results demonstrate the influence of thickness on the edge metallization profiles of the components of the loading device that mask the discs during sputtering.

Abstract

Methods to solve the problem of traceability and reproducibility for the measurement of parameters of second-generation photodetectors are proposed. An improved block diagram of the measurement methods and division into groups of the methods for measurement of second-generation photodetector devices and monitoring of auxiliary equipment is presented.

Abstract

Effect of illumination distribution in the circle of confusion on the measurement of the photoelectric coupling coefficient of the second-generation photodetector devices is studied. A theoretical study is carried out using mathematical modeling for illumination patterns of different structure and several ratios of photodetector pitch to the effective size of the photosensitive area. A formula is derived for calculation of the photoelectric coupling coefficient for a known distribution of photodetector sensitivity. The main conditions that affect the reliability of the results on the simulated measurement process are presented.

Abstract

Distributions of dark currents, lifetimes of minority carrier, and microdefects revealed by selective etching are compared. The main reason for increased dark currents and decreased photosensitivity in silicon photodiodes fabricated on n-type silicon using the Czochralski method are the generation–recombination processes on fine oxide precipitates.

Abstract

The results of the development of a recursive algorithm for temporal noise reduction with an adaptive threshold for thermal imaging systems are presented. This algorithm is designed to reduce the level of temporal noise based on the results of analyzing a sequence of images obtained using a thermal imaging channel. A mathematical model of the algorithm is provided, as well as the required amount of computing resources needed for its hardware implementation in field programmable gate arrays (FPGAs). Several characteristics of the thermal imaging system with the developed algorithm were measured and conclusions were made about the positive influence of the algorithm on its noise equivalent temperature difference (NETD).

Abstract

The resonant scattering spectra by the main magnetic mode of a subwavelength linear structure consisting of two dielectric flat thin rings located along the wave vector and excited by the displacement currents of the incident plane electromagnetic wave of the microwave range are investigated experimentally and using computer modeling. As distinct from a single ring, splitting of the resonant frequency is observed in the scattering spectra of the magnetic field in the far wave zone, near wave zone, and near the centers of the rings. The measured spectra coincide with the spectra resulting from computer calculations at all measurement points.