A formal comparative numerical study of the lubrication approximation and the shallow water equations (SWE) for three-dimensional Herschel-Bulkley viscoplastic flows is presented. The validity limits and predictive capabilities of these models are compared across various flow regimes, i.e., in terms of the aspect ratio, inclination angle, rheological properties, basal slipperiness, and Reynolds, Froude, and Bingham numbers. The models' abilities to capture flow deflections around obstructions are also evaluated. For validation, both model solutions are compared to dam-break experiments. In contrast to some previous works in the literature, both models are shown to adequately reproduce the experimental data in the low Reynolds number regime. The key difference arises during the early phase of a dam-break, where local Froude numbers are high, with the lubrication approximation appearing to overestimate front positions, whereas the SWE solutions align more closely with experimental observations. Furthermore, SWE provides better predictions of flow perturbations caused by obstructions and basal slipperiness. Overall, due to the inclusion of inertial effects, the present SWE model demonstrates broader predictive capability for viscoplastic flow dynamics than the lubrication approximation. However, both models converge as the inclination, aspect ratio, local perturbations, Froude and Reynolds numbers decrease, and as the Bingham number increases.
Understanding the distribution and conservation status of small carnivores is critical for informing management strategies in human-modified landscapes. We assembled a comprehensive dataset of jungle cat (Felis chaus) presence across India, drawing from over 26,000 camera trap locations, radio-telemetry data, published literature, secondary sources, and verified sightings. After filtering for spatial redundancy, we modeled species distribution using ecologically relevant covariates in both maximum entropy (MaxEnt) and random forest (RF) frameworks. The resulting ensemble model indicated that jungle cats are most likely to occur in warm, semi-arid regions with moderate vegetation cover and low to moderate levels of human and livestock disturbance. In contrast, they tend to avoid dense forests and highly transformed habitats.\nDespite theirbroad geographic distribution, jungle cats face increasing threats from habitat fragmentation, expanding infrastructure, road mortality, disease transmission from free-ranging dogs, and genetic introgression through hybridization with domestic cats. These pressures are particularly acute in peri-urban and agro-pastoral landscapes where jungle cats persist outside protected areas. Our findings underscore the importance of rural lifestyles with agro-pastoralism livelihoods for conserving the species along with grasslands, savanna and open forest systems to ensure the species’ long-term viability in a rapidly urbanizing landscape
Invasive seaweeds of the genus Caulerpa have benefited from human-driven environmental change to expand within coastal lagoons, frequently displacing native seagrasses. In the Mar Menor lagoon (southeastern Spain), Caulerpa prolifera has progressively expanded since the 1970s, coinciding with the decline of the native seagrass Cymodocea nodosa. Sediments colonized by Caulerpa are characterized by elevated sulfide concentrations, which are toxic to seagrasses, suggesting that sediment microbial communities may mediate competitive interactions between these macrophytes. However, the underlying microbial communities and metabolic potential remain poorly understood. Here, we characterized the taxonomic composition and functional capabilities of sediment microbial communities using 12 paired metagenomes and metatranscriptomes from areas dominated by either Ca. prolifera or Cy. nodosa. Caulerpa-associated sediments displayed a higher potential related to organic matter degradation and sulfate reduction. Several metagenome-assembled genomes (MAGs) encoded enzymes putatively involved in the degradation of pectin-like polysaccharides characteristic of the Caulerpa cell wall. Remarkably, the most highly expressed gene in Caulerpa-dominated sediments belonged to a Gammaproteobacteria MAG but lacked functional annotation based on in silico analyses. Recombinant production and functional characterization revealed that the enzyme encoded by this gene is able to breakdown bacterial peptidoglycan, due to endopeptidase or amidase activity. This result highlights the need to integrate metagenomics and metatranscriptomics with experimental validation to achieve a more comprehensive understanding of microbial functional capabilities, an integration that is still uncommon in the microbial ecology field. Overall, our findings provide mechanistic insight into the microbially mediated displacement of native seagrasses by Ca. prolifera in coastal lagoon ecosystems. ### Competing Interest Statement The authors have declared no competing interest.
Liquid limit has many applications in the field of geotechnical engineering such as soil classification, correlation studies, and the like. For these studies to yield meaningful outcomes, the liquid limit should be determined in the laboratory such that it represents the equilibrium value. In the present work, it is shown that the liquid limit determined in the laboratory without giving due consideration to the minimum maturation period of the soil represents only a transient value the use of which may lead to erroneous end results. This work also reveals that all fine-grained soils have a definite equilibrium maturation period, which is a function of clay mineralogical composition of the soils. In addition, to make the procedure of liquid limit determination more practical, an effort is made to limit the maturation period to 1 day through regression equations relating the equilibrium liquid limits to those determined allowing 1 day maturation period.
