Dominant Process Research Articles

Electrochemical behavior of 250-grade maraging steel by using Cascabela Thevetia as an organic inhibitor

ABSTRACT The Cascabela Thevetia (CT) plant, from the Apocynaceae family, is known for its use in traditional medicine across Central and South America and tropical Asia. This study examines the effect of CT leaf extract on the corrosion behavior of maraging steel in a 1 M H2SO4 solution. The addition of leaf extract (10 to 50 ml) reduced the corrosion rate (CR), with higher concentrations leading to greater inhibition efficiency, from 64.04% to 88.35%. Same trend is observed with rising temperatures. Electrochemical impedance spectroscopy (EIS) revealed that R ct (charge transfer resistance) increases with rising inhibitor concentration, signifying enhanced ‘blanketing’ properties of the protective film as the inhibitor concentration increases. Additionally, the calculated free energy value i.e. Δ G ∘ ≤ 20 KJ/mol suggests that physisorption is the dominant adsorption process. The reduction in the randomness of inhibitor molecules is evident from the calculated Δ S ∘ . Moreover, a positive Δ H ∘ value indicates that the inhibition process is endothermic. SEM analysis confirmed that the inhibitor reduced surface porosity, resulting in a smoother surface.

Integrated Simulation of Groundwater Flow and Nitrate Transport in an Alluvial Aquifer Using MODFLOW and MT3D: Insights into Pollution Dynamics and Management Strategies

This study employs an integrated numerical modeling approach using MODFLOW and MT3D to simulate groundwater flow and nitrate transport in the alluvial aquifer of Hennaya plain. The groundwater flow model was calibrated and validated against observed hydraulic heads, showing excellent agreement in both steady-state and transient conditions, with a correlation coefficients (R2) of 0.99 and 0.987, respectively. Meticulous calibration yielded adjusted hydraulic conductivity values between 10−1 and 10−11 m/s, with effective porosity ranging from 0.03 to 0.34 and total porosity values varying from 0.29 to 0.38 across the aquifer. Water budget analysis revealed that the aquifer’s primary recharge occurs from the southern side. Nitrate transport modeling indicated that advection is the dominant process, with contaminants migration predominantly occurring from south to north, following the groundwater flow direction. Pollution levels were found to decrease gradually with distance from sources, confirming agricultural activities and sewage disposal as primary contributors to nitrate contamination. Predictive scenarios over a 40-year period explored various management strategies, which suggest that maintaining current nitrogen input rates will lead to continued increases in nitrate pollution, while a 50% reduction in agricultural inputs could significantly improve groundwater quality. However, even with substantial reductions, nitrate concentrations are not expected to reach levels safe for drinking within the simulation timeframe. This study underscores the need for immediate and sustained action to address nitrate pollution in the Hennaya Plain aquifer, emphasizing the importance of stringent nitrogen management practices, particularly in the agricultural sector.

Enhancing aerobic composting of food waste by adding hydrolytically active microorganisms

The biomass of native microorganisms in food waste (FW) suitable for accelerated composting is initially low and requires time for adaptation. Adding of efficient hydrolytic microorganisms should be able to enhance compost-specific microbial activity, adjust microbial community structure, and potentially hasten FW biodegradation. This study aimed to identify bacterial and fungal strains with growth characteristics suitable for accelerating FW composting. Over 7 weeks, FW was composted in a pilot-scale test, either inoculated at the start or on day 28 with three different mixtures of 10 autochthonous Bacillus and Penicillium spp. strains known for their high hydrolytic activity. The effects of inoculation were assessed by measuring the rate of carbon dioxide (CO2) and ammonia (NH3) production and also the increase in temperature due to spontaneous exothermic activity of the enhanced microbial population degrading FW. Inoculation with Bacillus spp., particularly B. amyloliquefaciens and B. subtilis, at the beginning of composting increased CO2 production nearly 3-fold while maintaining stable ammonia production and temperature. The high concentration of Bacillus relative to native FW microorganisms led to dominant fermentation processes even in the presence of oxygen, resulting in moderate heat release and elevated production of volatile organic compounds. Introducing Penicillium spp. at a later stage (day 28) increased CO2 production nearly 2-fold, along with higher NH3 levels and temperature. These findings highlight the significance of inoculation timing and microbial composition in regulating metabolic pathways during FW composting degradation, offering insights for designing effective microbial formulations for composting.

High drug-loaded amorphous solid dispersions of a poor glass forming drug: The impact of polymer type and cooling rate on amorphous drug behaviour.

Enhancing the aqueous solubility via amorphization of crystalline poor glass-forming drugs represents a challenge, particularly when drug dosing is high. In such scenarios, there is often a need for high polymer loadings leading to an increase in the dosage form mass and less patient acceptability. This work investigated the role that polymer type and after-melt cooling rate had upon the amorphicity of solid dispersions (SDs) containing high levels of naproxen and three commonly used polymeric excipients: Eudragit® EPO, Kollidon® VA64, and Soluplus®. Using a combination of thermogravimetry, conventional and fast-scan DSC, oscillatory rheology, in silico Hansen solubility parameter computation, FTIR, and PXRD, we have shown that amorphicity could be affected by the cooling rate with the specific polymer type and amount playing a significant role in the degree of this impact. The amorphous drug content, evident at higher cooling rates, was found to be dependent on drug-polymer interaction and polymer melt viscosity. Higher polymer concentration and faster cooling produced less melt crystallization upon cooling, which was attributed to a shift in nucleation to lower temperatures where it could be inhibited by polymer matrix viscosity. Amorphous drug content, which contained drug nuclei, was evidenced by cold crystallization upon reheating. After 4 weeks of 'gentle' storage, cold crystallization increased if nucleation was the dominant process, whereas cold crystallization decreased if crystal growth prevailed. Storage at elevated temperature and humidity resulted in the absence of cold crystallization, and increased melt crystallisation. Thus, faster cooling could serve as an additional tool to improve amorphous yield and stability of high drug-loaded SDs, however, intermolecular polymer-drug interaction, melt viscosity of the drug-polymer matrix, and storage conditions are of critical importance to achieve this goal.

A multi-frequency, multi-epoch radio continuum study of the Arches cluster with the Very Large Array

Context. The Arches cluster, one of the most massive clusters in the Milky Way, is located about 30 pc in projection from the central massive black hole Sagittarius A* at a distance of ≈8 kpc from Earth. With its high mass, young age, and location in the Galaxy’s most extreme star forming environment, the Arches is an extraordinary laboratory for studying massive stars and clusters. Aims. Our objective is to improve our knowledge of the properties of massive stars and the Arches cluster through high-angular-resolution radio continuum studies. Methods. We observed the Arches cluster with the Karl G. Jansky Very Large Array in the C- and X-bands (central frequencies of 6 and 10 GHz respectively) in two epochs at C-band and five epochs at X-band throughout 2016, 2018, and 2022, covering time spans ranging from 22 days to 6 years. We used the A-configuration to achieve the highest possible angular resolution and cross-matched the detected point-sources with stars detected in the infrared, using proper motion catalogues to ensure cluster membership. Results. We report the most extensive radio point-source catalogue of the cluster to date, with a total of 25 radio detections (7 more than the most recent study). We also created the deepest (2.5 μJy in X-band) images of the cluster so far in the 4 to 12 GHz frequency range. Most of our stellar radio sources (12 out of 18) show a positive spectral index, indicating that the dominant emission process is free-free thermal radiation, which probably originates from stellar winds. We find that radio variability is more frequent than what was inferred from previous observations, and affects up to 60% of the sources associated with bright stellar counterparts, with two of them, F18 and F26, showing extreme flux variability. We propose four of our detections (F6, F18, F19, and F26) as primary candidates for colliding-wind binaries (CWBs) based on their consistent flat-to-negative spectral index. We classify F7, F9, F12, F14, and F55 as CWB binary candidates based on their high flux and/or spectral index variability, and X-ray counterparts. Thus, we infer a 14/23 ≈ 61% multiplicity fraction for the radio stars of the Arches cluster when combining our findings with recent infrared radial velocity studies.

Enhanced mechanical properties and mechanism of iron ore tailings-based geopolymers modified by municipal solid waste incineration fly ash

Iron ore tailings, coal fly ash and municipal solid waste incineration fly ash (MSWI FA), as solid waste, must be disposed of. Iron ore tailings, coal fly ash and MSWI FA were successfully prepared into high-performance geopolymer. The compressive strength of optimal geopolymer reached 57.89 MPa. Based on XRD, FTIR, SEM and chemical extraction analysis, C-(A)-S-H was the main gel product along with N-A-S-H. It was found that the dominant hydration process of geopolymer was changed from diffusion process (D) to phase boundary reaction process (I) after MSWI FA addition based on hydration reaction rate curves and dynamic simulation, releasing more hydration heat and generating more C(N)-A-S-H gels. Heavy metal content in the optimal geopolymer was below the limits of Class I screening value of development land (GB 36600-2018). Ef and Cf of the optimal geopolymer were 30.9 MJ/ton/MPa and 6.88 kg CO2/ton/MPa, affirming the viability of utilizing iron ore tailings, coal fly ash and MSWI FA as raw materials for geopolymer production, which provides a promising collaborative resource method of processing them.

Simulating hydrogen-controlled crack growth kinetics in Al-alloys using a coupled chemo-mechanical phase-field damage model

Environmentally Assisted Cracking (EAC) of 7xxx series aluminium alloys involves interactions between multiple physical phenomena, which ultimately influence the in-service life of critical components. In this work, we present a new model to study EAC in 7xxx series alloys, which is implemented in the multiphysics simulation framework, DAMASK. The chemo-mechanical model couples crack tip hydrogen generation, resulting from surface oxidation, and transport, with crystal-plasticity-governed intergranular crack propagation, through the microstructural trapping of hydrogen at dislocations, grain boundaries (GB), and crack tip stress fields. Large-scale simulations with realistic grain structures have been performed to provide novel insight into the dominant rate-controlling processes associated with intergranular EAC in 7xxx series aluminium alloys. The model was able to reproduce experimentally measured crack velocities under different loading conditions. Parametric studies indicate that, in addition to the GB network morphology, the crack growth rate was controlled by hydrogen generation at the crack tip with long-range diffusion having negligible influence. Additionally, the total hydrogen generated through crack tip oxidation appears to be more significant than the peak generation rate.

Groundwater hydrogeochemistry and potential health risk assessment through exposure to elevated arsenic in Darrang district of north bank plain of the Brahmaputra

The current study investigates groundwater contamination in Darrang district, situated in the flood-prone Brahmaputra Valley. This research evaluates the concentrations and geospatial distributions of iron, fluoride, and arsenic in groundwater samples (n = 347) and assesses their potential ecotoxicological risks to human health. Multivariate statistical techniques were used to investigate the sources and the mobilization mechanism of the contaminants in the aquifer system. The Piper and Gibbs plots reveal that silicate weathering, ion exchange, and mineral dissolution are the dominant processes influencing groundwater chemistry. Notably, higher pH levels (max = 8.5, mean = 7.4) are associated with alkaline desorption of arsenic from minerals. Cluster analysis also indicates the occurrence of pH induced carbonate weathering process implying weathering and active dissolution as a governing mechanism for arsenic release. The health risk assessments indicate significant non-carcinogenic and carcinogenic risks from prolonged exposure to arsenic, particularly for children. Spatial distribution maps identify areas most at risk of contamination and related health hazards. This is the first comprehensive analysis of groundwater contaminants in Darrang, providing valuable insights into the region’s water quality issues and supporting future groundwater management efforts in Brahmaputra floodplain region.

Diversity, composition, and assembly processes of bacterial communities within per- and polyfluoroalkyl substances (PFAS)-contained urban lake sediments

Per- and polyfluoroalkyl substances (PFAS) are widespread, highly persistent, and bio-accumulative compounds that are increasingly found in the sediments of aquatic systems. Given this accumulation and concerns regarding the environmental impacts of PFAS, their influence on sedimentary bacterial communities remains inadequately studied. Here, we investigated the concentrations of 17 PFAS in sediments from six urban lakes in Nanjing, China, and assessed their effects on the diversity, composition, potential interactions, and assembly mechanisms of sedimentary bacterial communities. Sediment concentrations of PFAS ranged from 4.70 to 5.28 ng·g−1 dry weight. The high concentrations of the short-chain perfluorobutanesulfonic acid (PFBS) suggested its substitution for the long-chain perfluorooctanesulfonic acid (PFOS). As alternatives to long-chain PFAS, short-chain PFAS had similar effects on bacterial communities. The short-chain perfluoropentanoic acid (PFPeA) and the long-chain perfluorotridecanoic acid (PFTrDA) were the most important PFAS related to the ecological patterns of the co-occurrence network and may alter the composition of the sedimentary bacterial communities in the urban lakes. The Anaerolineaceae family represented as keystone bacteria within the PFAS-affected bacterial co-occurrence network. Deterministic processes (65.9 %), particularly homogeneous selection (63.2 %), were the dominant process driving bacterial community assembly. PFAS promoted the phylogenetic clustering and influenced the community dispersal capabilities to shape bacterial community assembly. This study provides a comprehensive analysis of PFAS distribution in sediments across six urban lakes in Nanjing and provides novel insights into the effects of PFAS on sedimentary bacterial communities. Further research is required to elucidate the mechanisms underlying the impacts of PFAS on microbial communities and to evaluate their broader ecological consequences.

Pliocene to modern sediment routing in the Aare valley: implications for sediment recycling

Rivers transport sediment from source to sink, forming an essential part of sediment routing systems. Sediment generation is often assumed to be focused on the upstream reaches of mountainous rivers, characterized by high topographic gradients and high denudation rates. However, sediment recycling from uplifted and incised basin fills with relatively low topography, for example in foreland basins, may contribute significant amounts of material to the sediment cascade. Identifying and quantifying sediment recycling from such lowlands, however, is complicated by the lack of proxies sensitive to sediment recycling. Nevertheless, it is a crucial task in sedimentary system analysis, because any interpretation of allogenic or autogenic factors that control sediment dynamics in sedimentary systems strongly depends on where and how sediment is generated. We here present a sedimentary provenance study on the Aare river, a tributary to the Rhine river, which is sourced in the Swiss Alps and drains the Alpine foreland basin fill in its middle and lower reaches. Using garnet geochemistry as a proxy, the sediment sources in the Aare catchment can be precisely determined. We show that the modern Aare river carries garnet types incompatible with the crystalline rocks outcropping in the present-day catchment area, but compatible with Miocene sandstones of the foreland basin fill. By comparing modern-day fluvial sediment to Pleistocene and Pliocene paleo-Aare deposits we show that recycling from the foreland basin has been a dominant sediment generation process since the onset of the Pleistocene glaciation and the incision of river valleys. Instead, garnet compositions in a Pliocene terrace are more compatible with sediment sources in the Alpine crystalline core, pointing towards first-cycle sediment. Our study further emphasizes that (1) sediment recycling can be identified using appropriate provenance proxies, (2) provenance data are crucial to understanding the sediment dynamics and drainage evolution in Alpine river valleys, and (3) recycling from lowland basin fills may be a significant source of sediment that should be considered to prevent erroneous provenance interpretations.

The Future of Phosphoric Acid Production -Why We Have to Leave Trodden Paths.

This paper examines the need for innovation in phosphorus fertilizer production. An important area requiring action is the use of sulfuric acid in the wet chemical process (WCP), which is the dominant process in phosphate fertilizer production. About 50 % of the sulfuric acid produced worldwide is used for fertilizers, and ~95 % of the world's fertilizers are based on sulfuric acid. The latter is almost exclusively a by-product of gas and oil production, so the production of conventional P fertilizer is largely dependent on the availability of oil and gas. In addition to rendering P fertilizer production independent of fossil raw materials, energy consumption, CO2 emissions, phosphogypsum production and water consumption should also be considered. With the example of the PARFORCE process and the Improved Hard Process (IHP), new non-sulfuric acid-based alternatives are discussed with respect to overcoming the drawbacks of the classical WCP by being completely independent of fossil sources, working with renewable energies as the sole energy source, and the option of using seawater instead of fresh water. These new processes adhere to the principles of climate neutrality, zero waste production, low CO2 footprint, water conservation, renewable energy use, and energy and resource efficiency. This demonstrates what sustainable innovation can look like from a production perspective. The discussion will focus on whether current incentives are sufficient to realize the sustainability innovations discussed.

Did the terrestrial planets of the solar system form by pebble accretion?

The dominant accretion process leading to the formation of the terrestrial planets of the Solar System is a subject of intense scientific debate. Two radically different scenarios have been proposed. The classic scenario starts from a disk of planetesimals which, by mutual collisions, produce a set of Moon to Mars-mass planetary embryos. After the removal of gas from the disk, the embryos experience mutual giant impacts which, together with the accretion of additional planetesimals, lead to the formation of the terrestrial planets on a timescale of tens of millions of years. In the alternative, pebble accretion scenario, the terrestrial planets grow by accreting sunward-drifting mm-cm sized particles from the outer disk. The planets all form within the lifetime of the disk, with the sole exception of Earth, which undergoes a single post-disk giant impact with Theia (a fifth protoplanet formed by pebble accretion itself) to form the Moon. To distinguish between these two scenarios, we revisit all available constraints: compositional (in terms of nucleosynthetic isotope anomalies and chemical composition), dynamical and chronological. We find that the pebble accretion scenario is unable to match these constraints in a self-consistent manner, unlike the classic scenario.

Plasma-engineered sugarcane bagasse: a novel strategy for efficient mercury removal from aqueous solutions.

Metal ion adsorption using agro-industrial residues has shown promising results in remediating contaminated waters. However, adsorbent effectiveness relies on their properties, often necessitating processing for modification. Considering this, plasma treatment is effective in modifying material surfaces physically and chemically. This study investigated the modification of sugarcane bagasse (SB) using plasma treatment and evaluated its efficacy as a novel adsorbent for mercury removal from aqueous solutions. SB underwent low-temperature plasma treatment with sulfur hexafluoride (SF6) as the working gas, varying treatment times (2, 30, and 60min), and fixed powers (80, 190, and 300 W) at 16Pa pressure. Characterization via SEM/EDS, FTIR, XPS, and pHpzc revealed significant structural changes like increased in porosity and alteration in proportion atomic. Additionally, the successful incorporation of fluorine was confirmed in all treatment conditions, while sulfur was detected in only some samples. Amongst the tested conditions, the SB treated with 300 W for 60min demonstrated the highest mercury removal efficiency, achieving an impressive 83.67% removal rate compared to untreated SB, which yielded only 57.95%. The adsorption mechanism exhibited both physical and chemical behavior, with chemisorption being the dominant process. The Freundlich model provided the best fit to the experimental data, with an R2 value of 0.97. In conclusion, plasma treatment can be a promising alternative for improving the physical and chemical characteristics of SB adsorbents, thereby improving their efficiency in removing mercury from aqueous solutions.

Exploring α-synuclein Interaction Partners and their Potential Clinical Implications for Parkinson's Disease.

Alpha-synuclein aggregates are strongly associated with Parkinson's disease (PD), a degenerative neurological disorder characterized by a progressive loss in motor functions. Our study aimed to unravel the potential interaction partners of α-synuclein for exploring the synucleinpathy of PD related to α-synuclein aggregates. α-synuclein was expressed in E.coli and purified by affinity chromatography followed by isolation and identification of its interaction partners using pulldown assay coupled with LC-MS/MS. The impacts of the identified interaction partners on PD were evaluated based on GSE205450 dataset. Consequently, 157 proteins were identified by the criteria of unique peptide = 5. Four proteins including ACO2, ANT1, ATP5F1B and CKB were confirmed using immunostaining coupled with α-synuclein-pulldown assay. Transcriptomics assay showed that the dominant biological processes influenced by α-synuclein interaction partners with differential expression were energy metabolism. Together with GSE205450, Western blot assay showed that α-synuclein interaction partners involved in energy metabolism were down-regulated in PD patients and the MPTP-lesioned mice. ROC curves indicated their clinical implications as diagnostic indices of PD. Using ANT1 as an example, we found that protein aggregates formed by ANT1 and α-synuclein predominantly solely appeared in the cells and mice with PD-like variations. Thereby, low levels of the interaction partners of α-synuclein associated with energy metabolism were associated with PD pathogenesis via forming protein aggregates. This study provides an insight into developing innovative targets on PD based on synucleinpathy.

Effects of L-Aspartic Acid on Cr(VI) Adsorption onto the Lepidocrocite with Different Exposed Facets: Batch Experiments and In Situ ATR-FTIR Analysis

The adsorption of toxic metals onto iron oxides is a prevalent geochemical process in natural environments. Organic acids are known to modify the adsorption features of toxic ions through either competitive or cooperative effects. Nowadays, the toxic metal adsorption influenced by organic acids on iron oxides with varying facet exposures is not fully understood. This study explored how L-Aspartic acid (LA) influences Cr(VI) adsorption on two different exposure facets of lepidocrocite through batch adsorption experiments, in situ ATR-FTIR spectroscopy, and 2D-COS analysis. The results reveal that LA competes for available binding sites on lepidocrocite, consequently inhibiting the adsorption of Cr(VI). Rod-shaped lepidocrocite (R-LEP) owns more (001) facets and shows stronger Cr(VI) adsorption and LA competition than plate-like lepidocrocite (P-LEP), which mainly has (010) facets. The data for Cr(VI) uptake on both P-LEP and R-LEP within the effect of LA are well-fitted by the pseudo-second-order kinetics and the Freundlich isotherm model, suggesting chemical interaction as the dominant process for Cr(VI) coordination on lepidocrocite. Cr(VI) ions favor interaction with R-LEP over P-LEP, forming inner-sphere complexes on (001) facets. Concurrently, LA’s carboxyl groups can compete for the active sites on the lepidocrocite surfaces, engaging in anion exchange with hydroxyl groups, and forming outer-sphere and inner-sphere structures. This competitive effect is particularly pronounced in the R-LEP system. The current findings are expected to broaden insights into how the exposed facets of lepidocrocite influence the fate of Cr(VI) in the organic acid coexistence environment.

Adsorption of Orange G on Activated Porous Carbon Derived from Coal Tar Pitch: Experimental and DFT Study.

A coal tar pitch-based porous carbon adsorbent (CPA) was synthesized through a straightforward method involving the heating of a mixture of KOH and coal tar pitch (CTP). This CPA exhibited a high surface area of 1811.2 m2 g-1 and a large pore volume of 0.94 cm3 g-1 when prepared with a CTP to KOH mass ratio of 1:4 at 800 °C. Parameters such as the heating temperature and activator dose were optimized to enhance the adsorption efficiency. The prepared CPA was extensively characterized by SEM, XRD, FTIR, and BET measurements. Notably, CPA presented a distinct adsorption performance for Orange G (OG), achieving a maximum adsorption capability of 449.7 mg g-1. Kinetic studies indicated that the adsorption process followed the pseudo-second-order model, while the adsorption isotherm data demonstrated that both chemical and physical interactions favored OG adsorption. Thermodynamic analysis revealed that the adsorption of OG on CPA was spontaneous and exothermic and increased the entropy. Density functional theory (DFT) calculations provided insights into the adsorption mechanism, highlighting electrostatic interactions, hydrogen bonds, and π-π interactions as the dominant processes governing OG adsorption onto the adsorbent.

A new model of crater degradation on Ceres involving ice sublimation and talus formation

We report on the widespread occurence of talus on cerean crater walls using Dawn framing camera images. This is unexpected for a planetary body with no atmosphere like Ceres since the dominant process in crater degradation was expected to be topographic diffusion associated with impact gardening, like on the Moon or Mercury. To investigate why talus deposits are so common, and whether they could be related to the particular nature of Ceres’ ice-rich crust, we mapped them over the entire surface and studied their morphological characteristics. We classified the features into three different types, indicating their degree of preservation. Our results show that there is no trend between the total surface area of talus (whatever their degree of preservation) and latitude or longitude. However, we found that talus deposits tend to be observed within deep and young impact craters, and that certain craters expose a particularly large surface area of talus deposits: Dantu, Ninsar, Occator, Kupalo and Juling craters. It was also noted that well-preserved talus have a larger surface area than more degraded ones, and have ≈20 % more consolidated outcrops per km2. Age estimates from crater size frequency distributions for the host craters completed these observations, giving a mean age of 20−4+4 Ma for the craters hosting the more preserved talus deposits, and 280−8+8 Ma for the craters hosting the more degraded ones. By studying the slope of the talus deposits, we obtained a value of the angle of repose of the cerean regolith: 34.5°± 2.8°. We also found that the talus facing the poles are approximately 5°steeper than those facing the equator, have an 18 % larger surface area, and exhibit three times as many outcrops compared to talus on crater walls facing other directions. This suggests that the degradation of outcrops, the source of the material making up the scree, is sensitive to insolation. If we assume that the outcrops are made cohesive by the ice they contain, then we can conclude that sublimation of this ice leads to their fragmentation, at the origin of the talus material. We suggest that outcrop wall retreat due to ice sublimation feeding talus slopes is a predominant process in the earlier phase of crater degradation on Ceres supplanting impact gardening and topographic diffusion for some tens of million years. Once the maximum extent of the talus is reached, the progressively reduced debris production leads to a decreasing talus activity. Impact gardening then takes over and talus deposits are slowly degraded during the next few hundreds million years before fully disappearing. This has an influence on age estimations of the surface of Ceres, as the diameters of the craters grow larger over time due to the ice sublimation, resulting in a slight overestimation of the age of the dated cerean areas. In addition, in the perspective of future missions to Ceres, one of whose objectives would be to precisely quantify the ice content of the crust, the outcrops facing the poles and not yet degraded would be among the most interesting targets to explore.

Spatial Autocorrelation Methods in Identifying Migration Patterns: Case Study of Slovakia

The collapse of the socialist regime led to significant changes in migration patterns, garnering considerable attention in geographical research. However, despite the increased interest, many studies on internal migration lack a detailed analysis of its spatial aspects. Spatial autocorrelation methods can reveal spatial patterns, but so far they have not been applied in the detailed research of internal migration in post-socialist countries. The aim of this study is to explore the spatial patterns of internal migration with regard to intra-regional and inter-regional migration processes using selected indicators of spatial autocorrelation (Global Moran’s I, Anselin local Moran’s I and Getis-Ord Gi* statistic) with Slovakia as a case study. A partial goal is to evaluate the benefits of applying these methods in the assessment of internal migration. Local indicators of spatial autocorrelation demonstrated significant differentiation of both intra-regional and inter-regional migration processes. The dominant intra-regional process is the decentralization of the population, which is very intensive in the regions of the largest towns and cities. Inter-regional migration displays spatial polarisation, emphasizing the importance of the location of key economic centres. The methodology employed in this study clearly displays the clusters of municipalities with above-average and below-average values. This approach enables the identification and cartographic interpretation of specific municipalities where migration contributes the most to the spatial redistribution of the population. The study serves as a valuable framework for similar analyses, emphasizing the broader applicability of spatial autocorrelation methods in studying migration patterns.

Land-Use Impacts on Soil Erosion: Geochemical Insights from an Urban Drinking Catchment, South-Central Chile

We investigate the influence of land use and land cover (LU/LC) changes on soil erosion and chemical weathering processes within the Nonguén watershed in the Coastal Cordillera of south-central Chile. The watershed is divided into three sub-basins, each characterized by distinct LU/LC patterns: native forest and exotic plantations. A comprehensive geochemical analysis, including trace elements and lithium (Li) isotopes, was conducted on river water and suspended sediment samples collected from streams within these sub-basins to assess how land management practices, particularly plantation activities, influence the geochemical composition of river systems. Our results show that sub-basins dominated by exotic plantations exhibit significantly higher concentrations of major and trace elements in suspended sediments compared to sub-basins dominated by native forests. The elevated trace element concentrations are primarily attributed to increased physical erosion due to forestry activities such as clear-cutting and soil disturbance, which enhance sediment mobilization. Notably, concentrations of elements such as Fe, Al, and As in plantation-dominated sub-basins are raised to ten times higher than in native-dominated sub-basins. In contrast, sub-basins with native forest cover exhibit lower levels of sediment transport and trace element mobilization, suggesting that native vegetation exerts a stabilizing effect that mitigates soil erosion. Despite the substantial differences in sediment transport and element concentrations, Li isotopic data (δ7Li) show minimal fractionation across the different LU/LC types. This indicates that land use changes impact the chemical weathering processes less compared to physical erosion. The isotopic signatures suggest that physical erosion, rather than chemical weathering, is the dominant process influencing trace element distribution in plantation-dominated areas. The study provides critical insights into how forestry practices, specifically the expansion of exotic plantations, accelerate soil degradation and affect the geochemical composition of river systems. The increased sediment loads, and trace element concentrations observed in plantation-dominated sub-basins, raise concerns about the long-term sustainability of forest management practices, particularly regarding their impacts on water quality in urban catchment areas. These results are of significant relevance for environmental management and policy, as they underscore the need for more investigation and sustainable land use strategies to minimize soil erosion and preserve water resources in regions undergoing rapid LU/LC changes.

Study of D+→KS0K*(892)+ in D+→KS0KS0π+

Using a data sample of e+e− collisions corresponding to an integrated luminosity of 7.93 fb−1 collected with the BESIII detector at the center-of-mass energy 3.773 GeV, we perform the first amplitude analysis of the decay D+→KS0KS0π+. The absolute branching fraction of D+→KS0KS0π+ is measured to be (2.97±0.09stat±0.05syst)×10−3. The dominant intermediate process is D+→KS0K*(892)+, whose branching fraction is determined to be (8.72±0.28stat±0.15syst)×10−3, including all the K*(892)+ decays. Published by the American Physical Society 2024