Search Results (748)

The advanced determination of the type (foreshock–aftershock–swarm) of an ongoing seismic cluster is quite challenging; only retrospective solutions have thus far been proposed. In the period of January–March 2025, a seismic cluster, recorded between Santorini volcano and Amorgos Island, South Aegean Sea, caused considerable social concern. A rapid increase in both the seismicity rate and the earthquake magnitudes was noted until the mainshock of M_L = 5.3 on 10 February; afterwards, activity gradually diminished. Fault-plane solutions indicated SW-NE normal faulting. The epicenters moved with a mean velocity of ~0.72 km/day from SW to NE up to the mainshock area at a distance of ~25 km. Crucial questions publicly emerged during the cluster. Was it a foreshock–aftershock activity or a swarm of possibly volcanic origin? We performed real-time discrimination of the cluster type based on a daily re-evaluation of the space–time–magnitude changes and their significance relative to background seismicity using earthquake statistics and the topological metric betweenness centrality. Our findings were periodically documented during the ongoing cluster starting from the fourth cluster day (2 February 2025), at which point we determined that it was a foreshock and not a case of seismic swarm. The third day after the M_L = 5.3 mainshock, a typical aftershock decay was detected. The observed foreshock properties favored a cascade mechanism, likely facilitated by non-volcanic material softening and the likely subdiffusion processes in a dense fault network. This mechanism was possibly combined with an aseismic nucleation process if transient geodetic deformation was present. No significant aftershock expansion towards the NE was noted, possibly due to the presence of a geometrical fault barrier east of the Anydros Ridge. The 2025 activity offered an excellent opportunity to investigate deciphering the type of ongoing seismicity cluster for real-time discrimination between foreshocks, aftershocks, and swarms. Full article

The Paratethyan South Caspian and Mediterranean Levant basins relate to the significant hydrocarbon provinces of Eurasia. The giant hydrocarbon reserves of the SCB are well-known. Within the LB, so far, only a few commercial gas fields have been found. Both the LB and SCB contain some geological peculiarities. These basins are highly complex tectonically and structurally, requiring a careful, multi-component geological–geophysical analysis. These basins are primarily composed of oceanic crust. The oceanic crust of both the South Caspian and Levant basins formed within the complex Neotethys ocean structure. However, this crust is allochthonous in the Levant Basin (LB) and autochthonous in the South Caspian Basin (SCB). This study presents a comprehensive comparison of numerous tectonic, geodynamic, morphological, sedimentary, and geophysical aspects of these basins. The Levant Basin is located directly above the middle part of the massive, counterclockwise-rotating mantle structure and rotates accordingly in the same direction. To the north of this basin is located the critical latitude 35° of the Earth, with the vast Cyprus Bouguer gravity anomaly. The LB contains the most ancient block of oceanic crust on Earth, which is related to the Kiama paleomagnetic hyperzone. On the western boundary of the SCB, approximately 35% of the world’s mud volcanoes are located; the geological reasons for this are still unclear. The low heat flow values and thick sedimentary layers in both basins provide opportunities to discover commercial hydrocarbon deposits at great depths. The counterclockwise-rotating mantle structure creates an indirect geodynamic influence on the SCB. The lithospheric blocks situated above the eastern branch of the mantle structure trigger a north–northeastward movement of the western segment of the Iranian Plate, which exhibits a complex geometric configuration. Conversely, the movement of the Iranian Plate induced a clockwise rotation of the South Caspian Basin, which lies to the east of the plate. This geodynamic ensemble creates an unstable geodynamic situation in the region. Full article

Mineral waters from two tectonically active mountain systems within the Alpine-Himalayan orogenic belt, the Pamir and the Greater Caucasus (Elbrus region), were analyzed for ²²²Rn activity and ²³⁸U concentrations to establish correlations with geological conditions, physicochemical characteristics of water, and to assess the potential health risk associated with ²³⁸U and ²²²Rn. It was found that in mineral waters of the Pamir, the concentrations of ²³⁸U (0.004–13.3 µg/L) and activity of ²²²Rn (8–130 Bq/L) are higher than in the Elbrus area: 0.04–3.74 µg/L and 6–33 Bq/L, respectively. Results indicate that uranium mobility in water is strongly influenced by T, pH, and Eh, but is less affected by the age of host rocks or springs′ elevation, whereas radon activity in waters depends on the age of rocks, spring elevation, ²³⁸U content, and values of δ¹⁸O and δ²H in water. This study reveals fundamental geological distinctions governing uranium and radon sources in the mineral waters of these regions. Isotopic evidence (²²²Rn and ³He/⁴He) demonstrates crustal radon sources prevail in Pamir, whereas the Elbrus system suggests mantle-derived components. The U concentrations do not exceed 30 µg/L, and most water samples (94%) showed ²²²Rn activities below 100 Bq/L, complying with the drinking water exposure limits recommended by the World Health Organization and European Union Directive. However, in intermountain depressions of the Pamirs, at low absolute elevations (~2300 m), radon concentrations in water can increase significantly, which requires special attention and study. Full article

Mineral characterization of gold-bearing metasomatites in the Khaptasynnakh ore zone of the Anabar Shield is provided in detail. The following ore formation sequence of mineral associations in the Khaptasynnakh zone was found: pyrite and pyrrhotite → gersdorffite and molybdenite → chalcopyrite, sphalerite, and galena → bornite and chalcocite → tellurides, native gold, stibnite, cinnabar, and native bismuth. Native gold is characterized by varying fineness (550 to 926‰) and Cu impurity (up to 7.87%) values. Most often, it forms symplectite intergrowths with Au telluride–calaverite. Native gold and Au tellurides showed inclusions of chalcocite, bornite, altaite, tellurobismuthite, rickardite, petzite, and clausthalite. A two-stage formation process of the examined gold is suggested: Low-fineness gold was introduced into the system during early potassium metasomatism, while higher-fineness gold related to silica metasomatism resulted from its additional mobilization by fluid during late-stage formation. The low-temperature gold–telluride association observed in the mineral paragenesis of ore-bearing rocks, as well as its inclusions in native gold, suggests epithermal gold–telluride mineralization. Mineral inclusions examined in placer gold validate a genetic relation between the examined ores and gold placers in the Khaptasynnakh ore zone. Full article

Common ragweed, Ambrosia artemisiifolia (Asteraceae), is an invasive weed that causes problems in cropping systems and to human health both in its native range in North and Central America and the introduced range in Europe, Asia, Africa, and Australia. Ophraella communa, an herbivorous chrysomelid beetle from North America, was accidentally introduced into East Asia and Europe, where it significantly reduces weed populations and pollen production. Despite extensive research on its host specificity and risk assessment, the potential environmental risk of this biological control agent in southeastern Central Europe, one of the most heavily invaded areas by A. artemisiifolia, remains to be determined. This literature review attempts to summarize the results of host-range testing conducted so far and identifies plant taxa native to southeastern Central Europe that have not been tested yet. The results suggest that the host range of O. communa is not yet entirely clear, but may include some plant species from the tribes Heliantheae, Inuleae, Anthemideae, Cardueae, Astereae, and/or Coreopsideae. So far, only some of the 21 genera from those tribes with species in southeastern Central Europe have been tested. We therefore suggest further host specificity studies with representatives of these plant genera to fully assess the potential non-target risks by O. communa in agricultural and natural habitats. Full article

Abies nephrolepis and Picea jezoensis are native Pinaceae trees distributed in high mountainous regions of Northeast Asia (typically above ~1000 m a.s.l. on the Korean peninsula, northeastern China, Sakhalin, and the Russian Far East) and southern boreal forests, vulnerable to climate change and human disturbances, necessitating accurate habitat identification for effective conservation. While protected areas (PAs) are essential, merely expanding existing ones often fail to protect populations under human pressure and climate change. Using species distribution models with current and projected climate data, we mapped potential habitats across Northeast Asia. Spatial clustering analyses integrated with PA and land cover data helped identify optimal sites and priorities for new conservation areas. Ensemble species distribution models indicated extensive suitable habitats, especially in southern Sikhote-Alin, influenced by maritime-continental climates. Specific climate variables strongly affected habitat suitability for both species. The Kamchatka peninsula consistently emerged as an optimal habitat under future climate scenarios. Our study highlights essential environmental characteristics shaping the habitats of these species, reinforcing the importance of strategically enhancing existing PAs, and establishing new ones. These insights inform proactive conservation strategies for current and future challenges, by focusing on climate refugia and future habitat stability. Full article

Drought impacts agricultural production and regional sustainable development. Accordingly, timely and accurate drought monitoring is essential for ensuring food security in rain-fed agricultural regions. Alternating drought and flood events frequently occur in the Heilongjiang River Basin, the largest grain-producing area in Far East Asia. However, spatiotemporal variability in drought is not well understood, in part owing to the limitations of the traditional Temperature Vegetation Dryness Index (TVDI). In this study, an Improved Temperature Vegetation Dryness Index (ITVDI) was developed by incorporating Digital Elevation Model data to correct land surface temperatures and introducing a constraint line method to replace the traditional linear regression for fitting dry–wet boundaries. Based on MODIS (Moderate-resolution Imaging Spectroradiometer) normalized vegetation index and land surface temperature products, the Heilongjiang River Basin, a cross-border basin between China, Mongolia, and Russia, exhibited pronounced spatiotemporal variability in drought conditions of the growing season from 2001 to 2023. Drought severity demonstrated clear geographical zonation, with a higher intensity in the western region and lower intensity in the eastern region. The Mongolian Plateau and grasslands were identified as drought hotspots. The Far East Asia forest belt was relatively humid, with an overall lower drought risk. The central region exhibited variation in drought characteristics. From the perspective of cross-national differences, the drought severity distribution in Northeast China and Inner Mongolia exhibits marked spatial heterogeneity. In Mongolia, regional drought levels exhibited a notable trend toward homogenization, with a higher proportion of extreme drought than in other areas. The overall drought risk in the Russian part of the basin was relatively low. A trend analysis indicated a general pattern of drought alleviation in western regions and intensification in eastern areas. Most regions showed relatively stable patterns, with few areas exhibiting significant changes, mainly surrounding cities such as Qiqihar, Daqing, Harbin, Changchun, and Amur Oblast. Regions with aggravation accounted for 52.29% of the total study area, while regions showing slight alleviation account for 35.58%. This study provides a scientific basis and data infrastructure for drought monitoring in transboundary watersheds and for ensuring agricultural production security. Full article

Gut microbes are important for saproxylophagous insects, but little is known about the specific types of microbes that we can grow in the lab and how their diet affects them. We characterized aerobic culturable microbes from the superworm Zophobas atratus larvae reared on a standard diet (SD) and a fungal-based diet (FD) using the selective plating and 16S rRNA sequencing of isolates. Five functional groups were cultured: amino acid autotrophs, enterobacteria, yeasts, cellulolytic bacteria, and molds. A quantitative assessment revealed distinct diet-dependent patterns: SD-fed larvae showed the dominance of enterobacteria and amino acid autotrophs, while FD-fed larvae exhibited a higher abundance of enterobacteria and yeasts. Mold populations remained minimal under both diets. A phylogenetic analysis of bacterial isolates showed four core bacterial phyla (Pseudomonadota, Actinobacteria, Bacillota, and Bacteroidota) with diet-sensitive genus-level variations. Pseudomonadota dominated both diets, but certain genera were associated with different diets: Micrococcus and Brucella in the SD versus Citrobacter and Pseudomonas in the FD. Shared genera (Klebsiella, Enterobacter, and Bacillus) may represent a core culturable community. These findings demonstrate the influence of diet on culturable gut microbes while highlighting the need for complementary molecular approaches to study unculturable taxa. The isolated strains provide resources for investigating microbial functions in insect nutrition. Full article

Phenolic compounds, which are a large group of plant pigments, are recognized as important antioxidants. The potato (Solanum tuberosum L.), particularly the pigmented varieties, could be a source of natural anthocyanins for producing dietary foods. In this study, we analyzed forty potato specimens from our germplasm collection and breeding nurseries using high-performance liquid chromatography (HPLC) and second-order mass spectrometry to identify anthocyanins. We found seven main anthocyanins in potato tubers: delphinidin-3-glucoside, delphinidin-3-rhamnosyl-5-glucoside, petunidin-3-glucoside, malvidin-3-glucoside, cyanidin-3-glucoside, cyanidin-3-rhamnosyl-5-glucoside, and pelargonidin-3-glucoside. Two anthocyanins were found in potato inflorescences: peonidin-3-coumaroyl glucoside and cyanidin-3-coumaroyl glucoside. On average, varieties from the group with red-purple inflorescences contained 187.6 mg/kg of anthocyanins. Genotypes with white corollas had an anthocyanin content below 0.5 mg/kg or between 1.3 and 3.6 mg/kg. Two potato varieties, Vasilek (605.2 mg/kg) and Fioletovyi (501.1 mg/kg), with blue-purple corollas, had the highest total anthocyanin content. Studying the anthocyanin profile of leaves allowed us to identify eleven anthocyanins. The highest anthocyanin content (331.3 mg/kg) was found in varieties with purple or blue-purple tubers, while the lowest content (an average of 15.1 mg/kg) was found in varieties with yellow or cream tubers. Genotypes with purple and blue-purple tuber skin had an average anthocyanin content of 190.7 mg/kg. The group with yellow and cream tubers had an insignificant anthocyanin content (1.2 mg/kg). Varieties from the group with pink tubers had an average anthocyanin content of 43.2 mg/kg. Thus, this study identified diagnostic traits that could be used to assess the morphological characteristics of potato genotypes. Full article

This research examines a detailed metabolomic and comparative analysis of bioactive substances of soybean varieties: “Primorskaya-4”, “Primorskaya-86”, “Primorskaya-96”, “Locus”, “Sphere”, “Breeze”, “Namul”, and “Musson” by the laser confocal microscope CLSM 800 and the mass spectrometry of bioactive compounds by tandem mass spectrometry. The laser microscopy allowed us to clarify in detail the spatial arrangement of phenolic acids, flavonols, and anthocyanin contents in soybeans. Research has convincingly shown that the polyphenolic content of soybeans, and, in particular, the anthocyanins, are spatially localized mainly in the seed coat of soybeans. Tandem mass spectrometry was used to identify chemical constituents in soybean extracts. The results of initial studies revealed the presence of one hundred and fourteen compounds; sixty-nine of the target analytes were tentatively identified as compounds from polyphenol groups. Full article

Background: With an aging population, dementia prevalence is increasing in Korea. Vascular dementia (VaD), often caused by cerebrovascular disease (CVD), is more common in Korea compared to Western countries. Hwanhon decoction, a traditional medicine containing Ephedrae Herba, Armeniacae Semen, and Glycyrrhizae Radix et Rhizoma, is traditionally used for CVD-related loss of consciousness. This study aimed to assess the cognitive improvement and anti-inflammatory effects of Hwanhon decoction extract (HHex) in a mouse model of VaD caused by chronic cerebral hypoperfusion (CCH). Methods: Key pharmacologically active ingredients of Hwanhon decoction were identified using network pharmacology analysis. VaD was induced in C57Bl/6 male mice through bilateral common carotid artery stenosis (BCAS). Mice were divided into sham surgery, BCAS control, low-dose HHex (L-HHex), and high-dose HHex (H-HHex) groups (n = 5/group). After CCH induction, L-HHex or H-HHex was administered thrice weekly for six weeks. Cognitive function, inflammatory markers, and RNA sequencing data were analyzed. Results: HHex administration reduced cognitive impairment and mitigated CCH-induced astrocyte activation. Inflammatory responses mediated by reactive astrocytes were suppressed, and network pharmacology predicted central proteins influencing HHex’s activity. Conclusions: HHex alleviated cognitive dysfunction and reduced inflammation in a VaD mouse model, suggesting its potential as a therapeutic agent for vascular dementia associated with impaired cerebral blood flow. Full article

The radioisotopic dating of five stratigraphic levels within the Permian succession of the Kuznetsk Coal Basin refined the ages of the corresponding stratigraphic units and, for the first time, enabled their direct correlation with the International Chronostratigraphic Chart, 2024. The analysis revealed significant discrepancies between the updated ages and the previously accepted regional scheme (1982–1996). A comparison of regional stratigraphic units’ durations with estimated coal and siliciclastic sediment accumulation rates indicated that the early Permian contains the most prolonged stratigraphic hiatuses. The updated stratigraphic framework enabled re-evaluating the temporal sequence of regional sedimentological, volcano–tectonic and biotic events, allowing for more accurate comparison with the global record. Palaeoclimate reconstructions indicated that during the early Permian, the Kuznetsk Basin was characterised by a relatively warm, humid, and aseasonal climate, consistent with its mid-latitude position during the Late Palaeozoic Ice Age. In contrast, the middle-to-late Permian shows a transition to a temperate, moderately humid climate with pronounced seasonality, differing from the warmhouse conditions of low-latitude palaeoequatorial regions. The latest Lopingian reveals a distinct trend toward increasing dryness, consistent with global palaeoclimate signals associated with the end-Permian crisis. Full article

Ribes is the only genus in the Grossulariaceae family and holds considerable economic importance. Northeast Asia represents one of the major global centers of Ribes distribution. This study presents the first comprehensive investigation focused on this region, examining the diversity, distribution patterns, and environmental determinants of wild Ribes species through field surveys and a review of the relevant literature. Results indicate the presence of 36 species (including 8 varieties) from 7 subgenera of wild Ribes across Northeast Asia, predominantly belonging to the subgenera Berisia, Ribes, and Grossularia. The species are unevenly distributed throughout the region: (1) The Russian Far East exhibits the highest species richness, with 21 species from 5 subgenera, followed by Northeast China (16 species, 6 subgenera), Japan (12 species, 7 subgenera), Mongolia (10 species, 3 subgenera), South Korea (9 species, 5 subgenera), and North Korea (8 species, 5 subgenera). These findings suggest that the Russian Far East currently serves as the core distribution center for Ribes in Northeast Asia. (2) The species diversity of wild Ribes exhibits a unimodal latitudinal pattern, peaking between 47° N and 52° N. (3) A similar unimodal trend is evident along altitudinal gradients, with most species occurring between 500 m and 1500 m. (4) Species richness is primarily influenced by temperature stability and extreme low temperatures, followed by precipitation seasonality and elevation, while annual precipitation shows a relatively minor effect. This study offers crucial baseline data for the conservation and sustainable utilization of Ribes in Northeast Asia. Full article

This study reviews the melting rate of anthropogenic snow patches formed as a result of cleaning the territory of Yuzhno-Sakhalinsk city from snow and collecting it in designated areas known as snow dumps. Snow patches persisted at absolute altitudes of less than 50 m in the summers during the period of 2010–2022, except in 2017. The positive factor was the ratio of the relatively small area occupied by the anthropogenic snow patch and its significant height at the beginning of the melting period. The detailed observations of anthropogenic snow patch growth and melting were conducted by the authors starting in the winter season of 2017–2018. The snow volume collected in snow dumps during the winter season in Yuzhno-Sakhalinsk can reach 3000 m³. That is why it is necessary to determine how the anthropogenic snow patch will loosen the water through the warm season. Special models of anthropogenic snow patch melting do not exist. So, the authors review the ability of four glacier and snow cover melting model applications for such objects. The contribution of various parameters affecting the snow path melting rate was also determined. The collected factual data allowed for the development of empirical snow patch melting models. The largest errors resulting in the usage of reviewed models are related to the beginning (April) and ending (September–October) of the melting periods. Full article

Sterculia foetida L., commonly known as the Java olive, is a tropical tree species native to regions of East Africa, tropical Asia, and northern Australia. This study employs species distribution modeling (SDM) to predict the potential geographic distribution of S. foetida under current and future climate scenarios. Using 1425 occurrence data and 19 environmental variables, we applied an ensemble modelling approach of three algorithms: Boosting Regression Trees (BRT), Generalized Linear Model (GLM), and Random Forests (RF), to generate distribution maps. Our models showed high accuracy (mean AUC = 0.98) to indicate that S. foetida has a broad ecological niche, with high suitability in tropical and subtropical regions of north Australia (New Guinea and Papua), Southeast Asia (India, Thailand, Myanmar, Taiwan, Philippines, Malaysia, Sri Lanka), Oman and Yemen in the southwest of Asia, Central Africa (Guinea, Ghana, Nigeria, Congo, Kenya and Tanzania), the Greater and Lesser Antilles, Mesoamerica, and the north of South America (Colombia, Panama, Venezuela, Ecuador and Brazil). Indeed, the probability of occurrence of S. foetida positively correlates with the Maximum temperature of warmest month (bio5), Mean temperature of wettest quarter (bio8) and Precipitation of wettest month (bio13). The model results showed a suitability area of 4,744,653 km², representing 37.86% of the total study area, classified into Low (14.12%), Moderate (8.71%), and High suitability (15.02%). Furthermore, the study found that habitat suitability for S. foetida showed similar trends under both near future climate scenarios (SSP1-2.6 and SSP5-8.5 for 2041–2060), with a slight loss in potential distribution (0.24% and 0.25%, respectively) and moderate gains (1.98% and 2.12%). In the far future (2061–2080), the low scenario (SSP1-2.6) indicated a 0.29% loss and a 2.52% gain, while the high scenario (SSP5-8.5) showed a more dramatic increase in both loss (0.6%) and gain areas (3.79%). These findings are crucial for conservation planning and management, particularly in regions where S. foetida is considered invasive and could become problematic. The study underscores the importance of incorporating climate change projections in SDM to better understand species invasiveness dynamics and inform biodiversity conservation strategies. Full article