Search Results (181)

Helicobacter pylori (H. pylori) is a common gastric pathogen and a leading cause of non-cardia gastric cancers. Known determinants can affect the diagnostic accuracy of invasive clinical methods for H. pylori diagnosis. The objective of this study was to determine the diagnostic accuracy of the CLOtest, a rapid urease test, and the histopathologic examination compared with polymerase chain reaction (PCR) in esophagogastroduodenoscopy patients from a population with high prevalence and other risk factors that may influence diagnostic accuracy. From 2018 to 2022, patients were recruited from a medical care center serving the southwestern Navajo Nation. Summary statistics were calculated using PCR as the comparator to the CLOtest and histopathologic examination. Among the 466 study participants, 27.1% (95% CI 22.9, 31.7%) tested positive for H. pylori using PCR to detect pathogen DNA. Sensitivity was lowest for the CLOtest (57.0%; 95% CI 45.8, 67.6) and highest for the combination the CLOtest and histopathology (72.2%; 95% CI 62.8, 80.4). Patient history of infection or possible GI bleeding influenced sensitivity by over 5%. In high H. pylori prevalence areas, emphasis should be placed on ensuring adequate treatment of suspected positive infections as false-positive results were rare. Including a more sensitive test might reduce the number of individuals falsely classified as H. pylori negative. Full article

This paper investigates weak fault feature extraction in AUV thrusters under multi-input signal conditions. Conventional methods often rely on insufficient input signals, leading to a non-monotonic mapping between fault features and fault severity. This, in turn, makes accurate fault severity identification infeasible. To overcome this limitation, this paper increases the number of input signals by utilizing all available measurable signals. To address the problems arising from the expanded signal set, a signal denoising method that combines Feature Mode Decomposition and wavelet denoising is proposed. Furthermore, a signal enhancement technique that integrates energy operators and the Modified Bayes method. Additionally, distinct technical approaches for noise reduction and enhancement are specifically designed for different input signals. Unlike conventional methods that extract features directly from raw input signals, for fault feature extraction and fusion, this study transforms the signals into the time, frequency, and time–frequency domains, extracting diverse fault features across these domains. A sensitivity factor selection method is then employed to identify the sensitive features. These selected features are subsequently fused using Dempster–Shafer evidence theory to construct the final fault feature. Finally, fault severity identification is carried out using the classical grey relational analysis. Pool experiments using the “Beaver II” AUV prototype validate the effectiveness of the proposed method. Full article

Human-Wildlife conflict (HWC) presents a growing challenge for wildlife conservation, especially as species recover and reoccupy human-dominated landscapes, creating tensions between ecological goals and local livelihoods. Such conflicts are increasingly reported across Europe, including Romania, involving semi-aquatic species like the Eurasian beaver (Castor fiber L.) and Eurasian otter (Lutra lutra L.). Enhancing coexistence with wildlife through the integration of conflict mapping, stakeholder engagement, and spatial analysis into conservation planning is therefore essential for ensuring the long-term protection of conflict species. A mixed-methods approach was used, including structured surveys among stakeholders, standardized damage report collection from institutions, and expert field assessments of species activity. The results indicate that while most respondents recognize the legal protection of both species, a minority have experienced direct conflict, primarily with beavers through flooding and crop damage. Tolerance varied markedly among demographic groups: researchers and environmental agency staff were most accepting, whereas farmers and fish farm owners were the least accepting; respondents with no personal damage experience and those with university or post-secondary education also displayed significantly higher acceptance toward both species. Institutional reports confirmed multiple beaver-related damage sites, and through field validation, conflict forecast zones with spatial clustering in Harghita, Brașov, Covasna, and Sibiu counties were developed. These findings underscore the importance of conflict forecasting maps, understanding the coexistence dynamics and drivers of acceptance, and the need to maintain high acceptance levels toward the studied species. The developed maps can serve as a basis for targeted interventions, helping to balance ecological benefits with socioeconomic concerns. Full article

The largest Eurasian rodent, the Eurasian beaver Castor fiber, is known for its amphibious lifestyle that allows it to adapt its environment to its needs. Due to its lifestyle and evolutionary history, the beaver is characterized by a distinct, unique parasitofauna. In this context, the occurrence of mites from the Demodecidae family in the Eurasian beaver was investigated. The topography of the Demodex castoris was analyzed: it was previously known from a single record from a single skin location of this host. The mite was found in large numbers in various locations in the hairy skin, including the head, trunk, and limbs. In addition, a new species associated with hairless skin, mainly around the mouth, was discovered and described: Demodex ovaportans sp. nov. The females of this species carry the egg on the dorsal side of the podosoma, which may be a form of care and a previously unknown reproductive strategy in Demodecidae. Our findings confirm that a host-specific demodecid mite species associated with the hairy skin of the entire body is a universal model in mammals. They also emphasize the uniqueness of the beaver parasitofauna, as evidenced by the host specificity and the different biology of the demodecids described in it. Full article

Castor fiber birulai is a subspecies of the Eurasian beaver that has a relatively small population size compared to other Castor subspecies. There is limited genetic research on this subspecies. In this study, mitochondrial cytochrome b (Cytb) and D-loop sequences were analysed in genetic samples obtained from 19 individuals residing in the Buergen River Basin, Xinjiang, China. The Cytb region presented a single haplotype, whereas three haplotypes were identified in the D-loop region. The genetic diversity within the Chinese population was low (D-loop Hd = 0.444; Pi = 0.0043), markedly lower than that observed in other geographical populations of C. fiber. Phylogenetic reconstructions and haplotype network analyses revealed substantial genetic differentiation between C. f. birulai and other Eurasian lineages (Fst > 0.95), supporting the status of C. f. birulai as a distinct evolutionary lineage. Although the genetic distance between the Chinese and Mongolian populations was relatively small (distance = 0.00269), significant genetic differentiation was detected (Fst = 0.67055), indicating that anthropogenic disturbances—such as hydraulic infrastructure and fencing along the cross-border Bulgan River—may have impeded gene flow and dispersal. Demographic analyses provided no evidence of recent population expansion (Fu’s Fs = 0.19152), suggesting a demographically stable population. In subsequent studies, we recommend increasing nuclear gene data to verify whether the C. f. birulai population meets the criteria for Evolutionarily Significant Unit classification, and strengthening cross-border protection and cooperation between China and Mongolia. Full article

Numerous dark linear recurrent features called Recurring Slope Lineae (RSL) are observed on Martian surfaces, hypothesized as footprints of high-salinity liquid flow. This paper experimentally examined this “wet hypothesis” by analyzing the aspect ratios (length/width) of the flow traces on the granular material column to investigate how they vary with the granular material column, liquid and its flow rate, and inclination. While pure water produced low aspect ratios (<1.0) on the Martian regolith simulant column, high-salinity fluid (CaCl₂(aq)) traces exhibited significantly higher aspect ratios (>4.0), suggesting that pure water alone is insufficient to explain RSL formulation. Furthermore, the aspect ratios of high-salinity fluid traces on Martian regolith simulants were among the highest observed across all studied granular materials with similar particle sizes, aligning closely with actual RSL observed on Martian slopes. The results further suggest that variable ARs of actual RSL at the given slope can partly be explained by variable flow rates of high-salinity flow as well as salinity (i.e., viscosity) of flow. The results can be attributed to the unique granular properties of Martian regolith, characterized by the lowest permeability and Beavers–Joseph slip coefficient among the studied granular materials. This distinctive microstructure surface promotes surface flow over Darcy flow within the regolith column, leading to a narrow and long-distance feature with high aspect ratios observed in Martian RSL. Thus, our findings support that high-salinity flows are the primary driver behind RSL formation on Mars. Our study suggests the presence of salts on the Martian surface and paves the way for further investigation into RSL formulation processes. Full article

Over years of development in secure multi-party computation (MPC), many sophisticated functionalities have been made practical, and multi-dimensional operations occur more and more frequently in MPC protocols, especially in protocols involving datasets of vector elements, such as privacy-preserving biometric identification and privacy-preserving machine learning. In this paper, we introduce a new kind of correlation, called tensor triples, which is designed to make multi-dimensional MPC protocols more efficient. We will discuss the generation process, the usage, and the applications of tensor triples and show that they can accelerate privacy-preserving biometric identification protocols, such as FingerCode, Eigenfaces, and FaceNet, by more than 1000 times, with reasonable offline costs, and grant pre-computability for the secure matrix multiplication process in privacy-preserving machine learning protocols, such as SecureML and SecureNN, while achieving similar efficiency. Full article

The genus Travassosius Khalil, 1922, the smallest genus in the subfamily Trichostrongylinae (family Trichostrongylidae), primarily infects the only two extant beaver species worldwide and can be lethal in severe infections. However, the mitochondrial genome evolution of Travassosius remains poorly understood, and its phylogenetic placement within Trichostrongylinae is still unresolved. In this study, we applied both morphological techniques (differential interference contrast microscopy) and molecular tools (nuclear ITS2 and mitochondrial genome) to examine T. rufus Khalil, 1922. Specimens were collected from the Sino-Mongolian beaver, a subspecies of the Eurasian beaver native to the Ulungur River Basin in northern Xinjiang, China. This work presents the first complete mitochondrial genome sequence and annotation of T. rufus, and it is also the first mitochondrial genome reported for the genus Travassosius. The mitochondrial genome of T. rufus measures 13,646 bp and contains 36 genes, including 12 protein-coding genes (PCGs) (excluding atp8), 22 transfer RNA genes, and 2 ribosomal RNA genes. Phylogenetic analysis based on amino acid sequences of 12 mitochondrial PCGs strongly supports the distinctiveness of the genus Travassosius. Additionally, T. rufus appears to be closely related to Nematodirus within Trichostrongylinae. This study also addresses the possible consequences of parasitic infection for the Sino-Mongolian beaver and offers a scientific foundation for conserving this endangered subspecies and managing parasitic diseases in its population. Full article

Beavers (Castor fiber L.) are recognized as keystone ecological engineers who shape freshwater ecosystems by modifying hydrology, sediment dynamics, and biodiversity. Although beaver populations have recovered across Europe, including Romania, understanding the environmental factors driving their dam distribution remains limited. This study aimed to (i) characterize the physical and compositional features of beaver dams in the Râul Negru basin, Romania, (ii) model the environmental variables influencing the dam distribution using MaxEnt, and (iii) evaluate the implications for broader conservation strategies. Over a five-year survey covering 353.7 km of watercourses, 135 beaver families were identified, with an estimated population of 320–512 individuals. The dam dimensions showed strong correlations with the river slope, channel width, and wetness index. Predictive models based on LIDAR data achieved over 90% accuracy, outperforming SRTM-based models. The results reveal that topographic wetness, flow accumulation, and valley morphology are the strongest predictors of dam presence. These findings contribute to proactive beaver management strategies, highlighting areas of potential future expansion and offering data-driven guidance for balancing ecosystem restoration with human land use, contributing to the development of conservation strategies that balance ecosystem engineering by beavers with human land-use needs in Romania and across Europe. Full article

Historical archives hold untapped potential for understanding long-term biodiversity change. This study introduces computational approaches to historical ecology, combining archival research, text analysis, and spatial mapping to reconstruct past biodiversity patterns. Using the 1845 Bavarian Animal Observation Dataset (AOD1845), a comprehensive survey of vertebrate species across 119 districts, we transform 5400 prose records into structured ecological data. Our analyses reveal how species distributions, habitat associations, and human–wildlife interactions were shaped by land use and environmental pressures in pre-industrial Bavaria. Beyond documenting ecological baselines, the study captures early perceptions of habitat loss and species decline. We emphasise the critical role of historical expertise in interpreting archival sources and avoiding anachronisms when integrating historical data with modern biodiversity frameworks. By bridging the humanities and environmental sciences, this work shows how digitised archives and computational methods can open new frontiers for conservation science, restoration ecology, and Anthropocene studies. The findings advocate for the systematic mobilisation of historical datasets to better understand biodiversity change over time. Full article

Beavers play a key role in creating temporary water reservoirs that significantly impact the natural environment and local river hydrology. The primary aim of this study was to assess the potential of increasing the number of beaver dams (Castor spp.), as an alternative method of water retention in the environment. Research conducted on three small lowland streams in central Poland revealed that beaver dams, even in modified riverbeds, enable the formation of shallow floodplains and ponds. Innovative analyses considered the structural materials of the dams and their impact on river hydromorphology and sediment transport. The findings emphasise the importance of beavers in water retention processes, the stabilisation of water levels during low flows and the protection of biodiversity. The study also demonstrated that beaver dams play a critical role in storing surface- and groundwater, mitigating drought impacts, reducing surface runoff, and stabilising river flows. These constructions influence local hydrology by increasing soil moisture, extending water retention times, and creating habitats for numerous species. The collected data highlight the potential of beaver dams as a tool in water resource management in the context of climate change. Further research could provide guidance for the sustainable utilisation of beavers in environmental conservation strategies and landscape planning. Full article

Beaver populations in the U.S. northeast are rising, increasing the number of beaver dams and ponds in suburban watersheds. These new beaver ponds may impact the way that harmful algal blooms occur by changing biogeochemical cycling and sediment characteristics. In this study, piezometers, installed upstream and downstream of multiple dam structures were used to evaluate changes in nitrate and orthophosphate concentrations in surface and hyporheic water. Data were also collected with seepage meters, discharge measurements, lab and field-based analytical tests, and sediment samples. These were collected from beaver dams and paired non-beaver dams upstream of unimpounded reaches to look at the potential for dormant sediment-based cyanobacteria to bloom and produce toxins under ideal light and nutrient levels. Results indicate a significant increase in orthophosphate from upstream to downstream of beaver dams. Results also demonstrate that toxin potential did not increase between cyanobacteria in beaver pond sediment and the paired unimpounded sample; however, under ideal light and nutrient levels, sediment from a beaver dam led to faster cyanobacterial growth. These findings highlight that while beaver dams and impoundments function as nutrient sinks within the tributary watersheds, there are potential risks from downstream transport of bloom-inducing sediment following a dam collapse. Full article

Background: Citrobacter freundii (CFC) and Enterobacter cloacae (ECLC) species complexes represent important causes of hospital-associated infections, frequently are related to outbreaks, and have a great ability to develop antimicrobial resistance. We evaluated a large collection of CFC and ECLC isolates with decreased susceptibility to broad-spectrum cephalosporins (Ceph-DS) from United States (US) hospitals. Methods: A total of 43,325 Enterobacterales (1/patient) were collected in 2019–2023 and susceptibility tested by broth microdilution; among those, 5106 (11.8%) were CFC (n = 1374) or ECLC (n = 3732). Ceph-DS CFC (n = 379) and ECLC isolates (n = 1065), defined as isolates with ceftazidime MICs ≥ 16 mg/L and/or cefepime MICs ≥ 2 mg/L, were screened for β-lactamase genes by whole genome sequencing. Results: The most common ESBLs were CTX-M type (n = 98; 47.6% of ESBL producers), SHV type (n = 94; 45.6%), and OXA type (n = 78; 37.9%); ≥2 ESBLs were identified in 65 isolates (31.6%), mainly OXA-1/30 plus a CTX-M. A carbapenemase was identified in 55 of 64 (85.9%) carbapenem-resistant (CB-R) isolates, including KPC type (40 isolates; 62.5% of CB-R) and NDM-1 (16; 23.4% of CB-R). Aztreonam–avibactam was active against 99.6% of Ceph-DS and 100.0% of ESBL producers and CB-R isolates, including NDM producers. Ceftazidime–avibactam and meropenem–vaborbactam were active against 100.0% of ESBL producers (excluding carbapenemase co-producers) and 70.3–71.9% of CB-R isolates. Cefiderocol was active against 82.8% of CB-R isolates but only 46.7% of MBL producers. Conclusions: Aztreonam–avibactam was highly active against cephalosporin-nonsusceptible ECLC and CFC, including MBL producers. The activities of ceftazidime–avibactam, meropenem–vaborbactam, and cefiderocol were compromised against CB-R isolates due to the high frequency of NDM producers. Full article

Lead (Pb) is a persistent and toxic heavy metal that threatens aquatic ecosystems. Wetlands act as natural filters, while beaver dams influence sediment deposition and metal retention. This study investigates Pb fixation in wetland sediments by analyzing its spatial and temporal variations, considering organic matter content and sediment composition. Pb concentrations were determined using flame atomic absorption spectrometry (FAAS), and fixation processes were assessed using concentration coefficients relative to background values (15 µg g⁻¹, Lithuanian Hygiene Standard HN 60:2004). A total of 165 sediment samples were collected during the spring and the autumn of 2022 and 2023 across three study sites. The results indicate that Pb fixation strongly correlates with organic carbon content, while sediment texture influences its mobility. A key finding is that beaver dams contribute to Pb retention by altering hydrodynamic conditions and sedimentation patterns. Despite sediment stability, new Pb inputs continue to enter water bodies, depending on pollution sources. However, Pb concentrations remain within background levels and do not exceed the Maximum Allowable Concentration (MAC). These findings are essential for wetland conservation and contribute to sustainable strategies for mitigating heavy metal contamination in aquatic ecosystems. Full article

Virtual field trips in zoogeomorphology can allow students to explore the dynamic influence of beaver activity within the landscape. Education theory-informed virtual learning experiences (VLEs) of zoogeomorphologic topics, such as ecosystem engineers, are still underdeveloped for natural science learning communities. Through dam-building activities, beavers significantly alter stream hydrology, sediment transport, and vegetation organization and structure, promoting landscape heterogeneity. To effectively communicate this complexity of landscape modification, we developed an immersive virtual reality (VR) environment using historical photographs and detailed field notes to visualize the temporal and spatial transformations caused by beaver activity. A design and development process (TECCUPD), a philosophical framework for physical geography (TREE-PG), and a planning tool (VRUI conceptual model) are used to guide VLE architecture. Collectively, this information serves as a virtual proxy of an abandoned beaver pond field site to support student evaluation of the influence of sediment trapping and flooding on vegetation patterns on the landscape. This virtual place-based, experiential narrative environment is a proxy to capture the complexity of beaver-modified landscapes through ecological and geomorphological interactions. The integration of immersive VR technologies and generative artificial intelligence (AI) in higher education with learning theories that guide VR application design and development is applied in virtual field trips to support pedagogical goals and improve learning outcomes. Finally, we use an evaluation scale (TIPS) to assess the fidelity of learning theory implementation in a virtual field trip. Virtual field experiences in zoogeomorphology, informed by theory and utilizing immersive landscapes and scientific educational tools, can help students discern the effects of beavers on stream hydrology and geomorphic processes, as well as their potential role in mitigating water insecurity in climate adaptation efforts. Full article