Search Results (31,431)

The inability of geophysical methods to directly detect gold ore bodies remains a hot topic in the realm of gold geophysical exploration. Through the analysis of high-precision magnetic method, resistivity and induced polarization methods with the gradient arrays, electrical resistivity tomography, and well logging, combined with the discovery of gold mineralization in exploration trenches and boreholes, it has been found that gold mineralization can be classified into two types: terminal and channel. The terminal-type gold mineralization is marked by a buried depth of less than 30 m, accompanied by varying degrees of silicification and pyritization. In contrast, the channel-type of gold mineralization is buried deeper than 30 m and occurs within structural fractures or volcanic breccia mineralized alteration zones. The resistivity difference constitutes a significant geophysical indicator differentiating these two types of gold mineralization. Both types of gold mineralization are located adjacent to IP anomalies, potentially suggesting characteristics of low-sulfur gold mineralization. After comparing several globally typical epithermal gold deposits, we conclude that the findings presented in this paper encapsulate the geophysical traits of an un-eroded, low-sulfidation epithermal gold deposit. These insights offer a valuable reference for the direct detection of similar gold orebodies using geophysical methods. Full article

Establishing nature reserves is fundamental to promoting ecological civilization and ensuring the ecological security of sustainable development, as well as a key strategy for maintaining the integrity of the national ecosystem. In recent years, with the enhancement in environmental awareness, the role of nature reserves in maintaining ecosystem stability, protecting biodiversity, and promoting sustainable development has become increasingly prominent. As a crucial ecological defense line in China, studying the spatial distribution and influencing factors of nature reserves in Xinjiang is vital for regional ecological protection and resource management. In this study, we focused on the nature reserves in Xinjiang and used kernel density and standard deviation ellipse analysis methods to examine data from 1980, 1990, 2000, 2010, and 2020 in order to reveal the dynamics of spatial distribution, clustering characteristics, and evolutionary patterns, providing a scientific basis for optimizing the spatial layout of nature reserves in Xinjiang. We also employed a geographical detector model to assess the main influencing factors. This study shows that the number, area, and types of nature reserves in Xinjiang have rapidly increased, forming an integrated system predominantly composed of nature reserves. Their spatial distribution exhibits a northeast–southwest orientation and a ring-centered clustering pattern. This spatial differentiation is the result of the interaction between natural and human factors, manifesting as an enhanced effect among these factors. Full article

Gem-quality green vanadium grossular (var. tsavorite) is exclusively hosted in the Neoproterozoic Metamorphic Mozambique Belt (NMMB). The geochronology of tsavorite is limited until now, and the accurate crystallization age of the tsavorite in Kenya has remained unknown. Based on conventional gemological analyzing, by means of modern testing methods such as gemological analysis, UV-visible spectroscopy, Infrared spectroscopy, Raman spectroscopy, Electron probe, the spectral characteristics and chemical composition of tsavorite were determined, aiming to investigate the coloring elements of green garnets and trace the origin of tsavorite samples. The UV-Vis-NIR spectra and chemical composition analysis results show that vanadium and chromium are the main coloring elements in green tsavorite from Kenya. Combining the values of the δ¹⁸O (14.11‰) with the V/Cr ratio (around 4.4) of the tsavorite samples, the accuracy of the sample source has been identified. U–Pb dating of tsavorite from Kenya provides a concordant U-Pb age of 626.3 ± 4.6 Ma, in agreement with the weighted mean ²⁰⁶Pb /²³⁸U age of 625.9 ± 4.7 Ma (MSWD = 0.36), which indicated that Kenyan tsavorites were generated during the East African orogeny. Application of in situ laser U-Pb geochronology on gem-quality tsavorite to determine the mineralization time of Neoproterozoic Metamorphic Mozambique Belt of Kenya, which is the first step in characterizing the in situ dating analysis of gemstone tsavorite in Kenya mineral deposits Full article

The land use in agricultural areas contributes to economic growth while concurrently accompanied by a series of environmental pollution issues. Xingguo County, Ganzhou City, Jiangxi Province, is a typical agricultural area with selenium-rich soil, and the rice and navel oranges grown there have high nutritional value. This study analyzed the distribution of heavy metals in the soil of this area through the kriging interpolation method, evaluated the risks of heavy metals in the soil using different pollution index methods, and quantitatively analyzed their sources using principal component analysis (PCA) and positive matrix factorization (PMF), with the aim of protecting the ecological resources of this area and providing theoretical references for avoiding heavy metal pollution of crops in the soil. The research results indicate the following: (1) Based on the background values of Ganzhou, Jiangxi Province, all heavy metals have caused pollution to the soil except for As and Hg, among which Cd poses the highest potential ecological risk in the study area. According to the values of the Environmental Quality Standards for Soil (EQSS), the concentrations of heavy metals have not exceeded the standards and have relatively low potential ecological risks. (2) In terms of health risks, all soil heavy metals basically do not bring non-carcinogenic risks but acceptable carcinogenic risks to adults and children, except for Cd. The carcinogenic and non-carcinogenic risks of soil heavy metals for children are higher than those for adults, and the main exposure route is ingestion. Among different land use types, the carcinogenic and non-carcinogenic risks of soil heavy metals in orchards are the highest. (3) Combining the kriging interpolation method and the PCA and PMF models, it can be determined that there are two main sources of heavy metals in the study area: one is natural and the other is anthropogenic. Among the anthropogenic sources, agricultural sources contribute the most to soil heavy metal pollution. Through these research results, it can be found that soil heavy metal detection should be conducted in agricultural land, and risk-based management measures should be implemented. Full article

Increasing nitrogen (N) addition induces soil nutrient imbalances and is recognized as a major regulator of soil microbial communities. However, how soil bacterial abundance, diversity, and community composition respond to exogenous N addition in nutrient-poor and generally N-limited regions remains understudied. In this study, we investigated the effects of short-term exogenous N additions on soil bacterial communities using quantitative polymerase chain reaction (PCR) and Illumina Miseq sequencing in an in situ N addition field experiment. The results showed that a low nitrogen addition increased the observed species (Sobs) of the bacterial community, and with the increased nitrogen addition, the Sobs of bacteria gradually decreased, especially the unique OTUs. The relative abundance of Proteobacteria, Actinobacteria, and Gemmatimonadetes increased with increasing nitrogen addition, whereas the relative abundance of Chloroflexi and Firmicutes decreased. Soil properties play an important role in bacterial community structure at phylum or genus levels. Short-term nitrogen addition increased the proportion of nodes from Actinobacteria and Proteobacteria in the co-occurrence network and enhanced the stability of the microbial network. Actinobacteria may play an important role in constructing the network. Our study aims to explore the effects of nitrogen addition on the diversity, composition, and structure of soil bacterial communities in nutrient-poor areas caused by ecological disturbances. Full article

Revealing the level of cultivated land use efficiency and its influencing factors in the northern agro-pastoral ecotone from the perspective of population contraction can provide a decision-making reference for ensuring national food security and promoting the implementation of rural revitalization strategies. In this paper, using the stochastic frontier production function and a Tobit regression model, we reveal the current situation of rural population shrinkage in the agro-pastoral ecotone in northern China and the spatial and temporal evolution characteristics of cultivated land use efficiency, and identify influencing factors based on the perspective of “human–land”. The results show the following: (1) The rural population in all provinces and counties in the agro-pastoral ecotone in northern China showed a continuous loss trend. The southwest was a hot spot area for rural population reduction, and the northeast was a cold spot area for rural population reduction. (2) During 2000–2020, the cultivated land use efficiency in the agro-pastoral ecotone in northern China showed a fluctuating upward trend, rising from 0.595 in 2000 to 0.754 in 2020. Spatially, the cultivated land use efficiency in the agro-pastoral ecotone in northern China showed the characteristic of being higher in the northeast and lower in the southwest, and the cultivated land use efficiency in some counties in the central and southwestern parts showed a downward trend. (3) The cultivated land use efficiency in the agro-pastoral ecotone in northern China is comprehensively affected by multiple factors. The following factors were determined, presented in descending order of the absolute value of influence degree: proportion of the population over 65 years old > multiple cropping index > proportion of cultivated land area > proportion of rural population > average years of education > population change rate. Based on these results, this paper puts forward measures to improve cultivated land use efficiency in the agro-pastoral ecotone in northern China from the perspective of population shrinkage, so as to provide references for ensuring national food security and promoting rural revitalization. Full article

Resolving the status of soil carbon with land cover is critical for addressing the impacts of climate change arising from land cover conversion in boreal regions. However, many conventional inferential approaches inadequately gauge statistical significance for this issue, due to limited sample sizes or skewness of soil properties. This study aimed to address this drawback by adopting inferential approaches suitable for smaller samples sizes, where normal distributions of soil properties were not assumed. A two-step inference process was proposed. The Kruskal–Wallis (KW) test was first employed to evaluate disparities amongst soil properties. Generalized estimating equations (GEEs) were then wielded for a more thorough analysis. The proposed method was applied to soil samples (n = 431) extracted within the southern transition zone of the boreal forest (49°–50° N, 80°40′–84° W) in northern Ontario, Canada. Sites representative of eight land cover types and seven dominant tree species were sampled, investigating the total carbon (C), carbon-to-nitrogen ratio (C:N), clay percentage, and bulk density (BD). The KW test analysis corroborated significance (p-values < 0.05) for median differences between soil properties across the cover types. GEEs supported refined robust statistical evidence of mean differences in soil C between specific tree species groupings and land covers, particularly for black spruce (Picea mariana) and wetlands. In addition to the proposed method, the results of this study provided application for the selection of appropriate predictors for C with digital soil mapping. Full article

In line with the Italian “Farmers-Nature Project” aimed at reducing conflicts between wild predators and livestock farmers, the spatiotemporal activity of the red fox was monitored in a protected area of central Italy over a one-year period. In parallel, farmers living in the study area were asked to participate in an interview about their perception of the red fox and its predatory activity towards livestock. Analysis of data obtained by camera trapping revealed that a higher number of red fox sightings was recorded in February and March in relation to the search for food, while a lower number was recorded in July when food is more abundant. Red fox primarily moves at night, with a peak of activity between 9 and 10 p.m., staying around an area close to the den. Interviews with farmers revealed a generally positive view of the red fox, as its predation on livestock was rare, suggesting that the fox can find sufficient food resources in the environment. Full article

As climate change intensifies, cities face growing risks. Natural disasters underscore the vulnerabilities inherent in urban systems. Resilience provides a dynamic and developmental approach to urban disaster management. This study focuses on Shanghai to examine its urban disaster resilience by analyzing compounded disaster scenarios, the impacts on vulnerable entities, and spatial differentiation within the city. Specifically, it explores the internal mechanisms of resilience across three dimensions, functional, procedural, and systemic, forming the foundation for the model. A three-dimensional urban disaster resilience model is then constructed. The first-level indicators afford the overall framework, the second-level indicators emphasize resilience based on resources and geographical endowments, and the third-level indicators are tailored to the current political, economic, cultural, and social characteristics of the region. Using actual collected data, along with the Analytic Hierarchy Process (AHP) and expert judgment methodologies, the resilience indicator system for Shanghai can scientifically reflect the city’s capacity to withstand disasters and offers a foundation for developing targeted solutions. The results highlight the framework’s potential generalizability to other metropolises and its contributions to global resilience research. Full article

Roadside tree segmentation and parameter extraction play an essential role in completing the virtual simulation of road scenes. Point cloud data of roadside trees collected by LiDAR provide important data support for achieving assisted autonomous driving. Due to the interference from trees and other ground objects in street scenes caused by mobile laser scanning, there may be a small number of missing points in the roadside tree point cloud, which makes it familiar for under-segmentation and over-segmentation phenomena to occur in the roadside tree segmentation process. In addition, existing methods have difficulties in meeting measurement requirements for segmentation accuracy in the individual tree segmentation process. In response to the above issues, this paper proposes a roadside tree segmentation algorithm, which first completes the scene pre-segmentation through unsupervised clustering. Then, the over-segmentation and under-segmentation situations that occur during the segmentation process are processed and optimized through projection topology checking and tree adaptive voxel bound analysis. Finally, the overall high-precision segmentation of roadside trees is completed, and relevant parameters such as tree height, diameter at breast height, and crown area are extracted. At the same time, the proposed method was tested using roadside tree scenes. The experimental results show that our methods can effectively recognize all trees in the scene, with an average individual tree segmentation accuracy of 99.07%, and parameter extraction accuracy greater than 90%. Full article

Background/Objectives: Culex species mosquitoes are globally distributed and transmit several pathogens that impact animal and public health, including West Nile virus, Usutu virus, and Plasmodium relictum. Despite their relevance, Culex species are less widely studied than Aedes and Anopheles mosquitoes. To expand the genetic tools used to study Culex mosquitoes, we previously developed an optimized plasmid for transient Cas9 and single-guide RNA (sgRNA) expression in Culex quinquefasciatus cells to generate gene knockouts. Here, we established a monoclonal cell line that consistently expresses Cas9 and can be used for screens to determine gene function or antiviral activity. Methods: We used this system to perform the successful gene editing of seven genes and subsequent testing for potential antiviral effects, using a simple single-guide RNA (sgRNA) transfection and subsequent virus infection. Results: We were able to show antiviral effects for the Cx. quinquefasciatus genes dicer-2, argonaute-2b, vago, piwi5, piwi6a, and cullin4a. In comparison to the RNAi-mediated gene silencing of dicer-2, argonaute-2b, and piwi5, our Cas9/sgRNA approach showed an enhanced ability to detect antiviral effects. Conclusions: We propose that this cell line offers a new tool for studying gene function in Cx. quinquefasciatus mosquitoes that avoids the use of RNAi. This short study also serves as a proof-of-concept for future gene knock-ins in these cells. Our cell line expands the molecular resources available for vector competence research and will support the design of future research strategies to reduce the transmission of mosquito-borne diseases. Full article

The rise in performance and health concerns presents a complex challenge to workplace well-being. While existing research highlights the positive impact of exposure to nature on well-being, there is a gap in supporting biophilic building designs in workplaces. This study addresses this issue by introducing a Type-1 Interval Fuzzy Set (IFS) framework to assess workplace health, and recommends Nature-Based Solutions (NbS) for enhancement. The proposed framework comprises two fuzzy subsystems targeting environmental comfort and occupational health that are integrated into a third subsystem to provide tailored NbS recommendations. A case study conducted in a coworking space validated the framework’s practical application, revealing significant improvements in environmental and occupational conditions. Key findings include a reduction in absenteeism, enhancement in employee satisfaction, and creation of more comfortable and restorative environments. Recommendations, such as green walls, indoor gardens, and natural light filters, have been shown to effectively mitigate discomfort and promote well-being. The framework demonstrated flexibility in managing uncertainties, optimizing resource allocation, and providing targeted interventions for workplace conditions. These results highlight the framework’s potential as a robust decision-support tool for improving workplace health and well-being through systematic and evidence-based strategies. Full article

The deep-sea ecosystem, a less-contaminated reservoir of antibiotic resistance genes (ARGs), has evolved antibiotic resistance for microbes to survive and utilize scarce resources. Research on the diversity and distribution of these genes in deep-sea environments is limited. Our metagenomics study employed short-read-based (SRB) and assembled-contig-based (ACB) methods to identify ARGs in deep-sea waters and sediments and assess their potential pathogenicity. SRB prediction was found to be more effective for studying the abundance and diversity of these genes, while combining both methods better illustrated the relationship of ARGs with the hosts. Deep-sea waters (DSW) and trenches had the highest diversity of ARGs, including β-lactams, multidrug resistance genes, and rifamycins. Mobile genetic elements, such as IncQ and RP4 plasmids, were also identified. The ratio of nonsynonymous to synonymous substitutions (pN/pS) values of these genes suggest different evolutionary strategies in response to deep-sea conditions and possible human impacts. These resistome profiles provide valuable insights into their natural origins as well as the ecological and evolutionary implications of antibiotic resistance in deep-sea ecosystems. The exploration of the global distribution of ARGs in diverse deep-sea environments is a novel approach that will assist in understanding their potential reservoirs and evolutionary mechanisms. Therefore, employing a comprehensive approach to studying ARGs is particularly necessary. Unique microbial life in deep-sea ecosystems, especially in deep-sea cold seeps sediments (DSCSS), deep-sea waters (DSW), and trench waters (TW), could be a valuable source of new antibiotics and resistance discovery. Full article

Salt lake brine-type potassium-lithium deposits play an important role as a strategic mineral resource that is in short supply in China and the rest of the world. In the case of long-term, high-intensity exploitation of brine resources, if large-scale active faults are encountered, these faults will form advantageous channels for brine migration. In some special cases, the surface fresh water leaks into these advantageous channels and will soon produce a large amount of fresh water in the brine mining well area, resulting in the destruction of the mining well and in the reduction in the potassium lithium grade of the brine. Based on the monitoring of the chemical components and hydrogen and oxygen isotopes of brine in mining wells, combined with the principle of stable isotope conservation, the influence of freshwater leakage accidents on brine extraction wells was quantitatively calculated. The amount of fresh water added to brine by accident is approximately 78%. This further indicates that it is necessary to strengthen long-term monitoring of the chemical components of confined brine to ensure sustainable and stable production. Full article

In 2023, exceptionally few salmon (Salmo salar) ascended from the Baltic Sea to spawn in the Rivers Tornionjoki and Simojoki, regardless of the proper number of smolts descending to the sea in preceding years. We investigated how the numbers of age-0 and young herring (Clupea harengus) and sprat (Sprattus sprattus), which are the principal prey species of salmon in the Baltic Proper, the main feeding area of these salmon, as well as the amount of lipid obtained from them and their protein-to-lipid ratio, correlated with the number of returning salmon and the thiamine status of spawning salmon. The fewer the 0-year-old herring were and the more abundant were the youngish sprat in the Baltic Proper when the post-smolts arrived there, and the greater the lipid content and lower the protein-to-lipid ratio of the prey fish, the fewer salmon returned to the Rivers Tornionjoki and Simojoki to spawn two years later. The number of returning salmon was lowest with a high ratio of youngish sprat, 1–3 years old, regarding the River Tornionjoki and 1–2 years old regarding the River Simojoki post-smolts, to 0-year-old herring, which were of a suitable size to be the prey for the post-smolts upon their arrival in the Baltic Proper. In 2021, the ratios were lowest due to the record-low number of 0-year-old herring. The poor thiamine status of spawning salmon was also associated with the high lipid content of available prey fish and with the abundance of youngish sprat, which have twice the lipid content of age-0 herring. Our findings parallel the observations in the early 1990s when post-smolt survival declined concurrently with the outbreak of thiamine (vitamin B1) deficiency, M74. We conclude that consuming high-lipid marine fish reduces the survival of post-smolts and, thus, the number of returning salmon, in addition to causing thiamine deficiency. Full article