The University of the Ryukyus (琉球大学, Ryūkyū Daigaku), abbreviated to Ryūdai (琉大), is a Japanese national university in Nishihara, Okinawa Prefecture, Japan. Established in 1950, it is the westernmost national university of Japan and the largest public university in Okinawa Prefecture. Located in the Senbaru neighborhood of the town of Nishihara, its campus borders both the village of Nakagusuku and the city of Ginowan.
From September 2023 to September 2024, the potential intermediate hosts of Angiostrongylus cantonensis (Nematoda: Angiostrongylidae) were investigated on northern Okinawa Island, Japan, where infection of endangered rodent species is a conservation concern. Third-stage larvae of A. cantonensis were detected in Tanychlamys indica (Stylommatophora: Ariophantidae), a globally invasive terrestrial snail species recently established on Okinawa Island. Notably, infected T. indica were primarily collected from forest edges, indicating a potential ecological interface between this invasive host and native forest ecosystems. These findings highlight the necessity to monitor the spread of T. indica from both the conservation and public health perspectives.
To develop a technology that simultaneously performs clathrate hydrate-based carbon capture and desalination, phase equilibrium conditions of clathrate hydrate-forming systems consisting of carbon dioxide–nitrogen mixed gases and sodium chloride aqueous solutions were measured. The energy requirement associated with seawater desalination and the second stage of a multistage carbon dioxide separation process was also examined. Using mixed gases with carbon dioxide mole fractions ranging from 0.61 to 0.68 in equilibrium with sodium chloride aqueous solutions with mass fractions from 0.035 to 0.105, the measured phase equilibrium temperatures ranged from 269.8 K to 275.8 K, with corresponding equilibrium pressures ranging from 2.12 MPa to 4.02 MPa. Under the assumed operating pressure of 2.8 MPa, the sum of the energy required to supply the cold thermal energy and compress the gas corresponds to 199 kWh–220 kWh when expressed per ton of carbon dioxide captured, and 68.5 kWh–75.6 kWh when expressed per cubic meter of water obtained. A large fraction of the energy is consumed for supplying cold thermal energy to remove the enthalpy change of clathrate hydrate formation and for gas compression. Therefore, the results indicate that effective utilization of cold thermal energy from liquefied natural gas regasification, operation at lower temperatures and pressures, and the introduction of guests that enable operation at reduced pressures are promising strategies for reducing the overall energy demand. These strategies may facilitate the development of hydrate-based technologies for simultaneous carbon capture and desalination of high-salinity water streams, including produced water and seawater.
Abstract Detailed measurements of motions, including turbulence structures, in high-concentration sediment flows are difficult, and their dynamics remain poorly understood. Interface-resolved large eddy simulation (IRLES) is a numerical simulation method that uses computational grids smaller than individual particles to resolve the flow using large eddy simulation and simultaneously solves the particle–fluid coupled motions. In this study, the turbulence structure of sediment flows was analyzed using IRLES. The IRLES simulations using gravel-shaped particles were conducted for uniform flows of sediment–water mixtures with uniform grain size under three different flume slope conditions: 6.4°, 10.5°, and 14.4°. The simulated particle volume concentrations of 0.086 (6.4°), 0.173 (10.5°), and 0.298 (14.4°) showed good agreement with predictions of the equilibrium sediment concentration equation, with a maximum error E c of 13%. Turbulence energy spectra of sediment flows were obtained at different heights to analyze turbulent structures. The simulations indicated that, in the steep-slope case, the peak of the turbulence energy for high-concentration sediment flows occurred closer to the free surface than in low-concentration flows. To clarify the characteristics of the turbulent energy spectra of sediment flows in comparison with those of water-only flows, an additional simulation was conducted for the 6.4° slope condition in which the bed particles were fixed. In the water-only simulation, the energy spectra, when nondimensionalized by the local turbulent kinetic energy, collapsed onto nearly the same curve at all heights. In contrast, in sediment flows, the decay of the energy spectrum at high wavenumbers became less pronounced with increasing particle concentration near the bottom of the flow. In high-concentration flows, this trend of reduced spectral decay at high wavenumbers persisted even near the free surface, indicating coexistence of vortices across different scales and complex vortex dynamics near the surface.
With the rapid uptake of environmental DNA (eDNA) metabarcoding for a wide range of conservation and management uses, there is a growing need for guidance and best practices for species identification. A range of methodological and interpretive decisions influences taxa assignment. Here we provide a review and perspective of pitfalls and issues that can impact accurate taxonomic assignment across the full eDNA metabarcoding workflow: primer selection, lab handling, bioinformatics, taxonomic assignment, and communication of results. This paper addresses the complexities and challenges of the metabarcoding-based species identification process, offering recommendations for robust workflows and effective communication of findings. Accurate interpretation and communication of eDNA metabarcoding results requires an acknowledgment of methodological limitations such as incomplete reference databases, contamination risks, ambiguous sequences, and detection biases. Thus, we argue that transparency of methods and limitations, alongside proactive alignment of decisions with project objectives are critical for the successful application of eDNA metabarcoding in conservation and management decisions. We provide guidance for developing protocols that support species identification from eDNA metabarcoding sequences, and give recommendations on communication strategies for stakeholders and end users. To support these recommendations, we outline steps in the workflow that can impact species identification, with a discussion of the strengths and weaknesses at each stage. Ultimately, this guidance can improve the accuracy, reliability, and usability of eDNA and other metabarcoding and amplicon sequencing approaches to species identification while fostering trust and understanding among diverse end users.
