Subterranean spaces, such as caves with openings to the surface, represent unique environments characterized by limited resources derived from photosynthetic primary production. Consequently, organic inputs from organisms inhabiting above- and belowground habitats, such as bats, play a crucial role in maintaining cave ecosystems. However, in show caves converted into tourist attractions, environmental changes have progressed without sufficient ecological assessment. One important factor is the impact of photosynthetic organisms colonizing around artificial lights, known as lampenflora, on cave ecosystems. Lampenflora growth may influence invertebrate distribution and resource use; however, its impact on both aspects has been poorly evaluated. In this study, we investigated the effects of lampenflora growth on invertebrate distribution and resource use in a well-managed Japanese show cave, Ryusen-do, while considering the influence of bat fecal deposition. Our generalized linear mixed model revealed that bat feces and guano are the primary factors determining invertebrate distribution within the cave. We also suggest that lampenflora growth negatively affected troglomorphic species but may benefit non-troglomorphic species by providing habitat structure and additional food resources through detritus. Stable isotope analyses further supported differences in the food resources used by invertebrates between tourist and non-tourist areas. Because the impact of lampenflora was detected even in the well-managed Ryusen-do Cave, we suggest that less well-managed show caves may experience more severe ecological impacts due to lampenflora invasion. Our findings highlight the importance of evaluating and managing lampenflora as part of show cave conservation.
Mechanochromic luminescence (MCL), defined as a fluorescence color change induced by mechanical stimulation, has recently attracted considerable attention due to its sensitivity to molecular packing and intermolecular interactions. In this study, we synthesized three regioisomers of dibenzoylmethanatoboron difluoride (BF2DBM) with a methoxy substituent at the ortho, meta, or para position of one phenyl ring ( o -, m -, and p -a2bBF 2 ), while the other ring was substituted with di-tert-butyl groups. In addition, two crystal polymorphs of p -a2bBF 2 (Form I and Form II) were investigated. Clear MCL behavior was observed for o -a2bBF 2 and for Form I of p -a2bBF 2 . In contrast, m -a2bBF 2 exhibited only a minor spectral change without an apparent fluorescent color change, and Form II showed virtually no color change. Spectroscopic and crystallographic analyses revealed that these contrasting responses originate from differences in molecular packing. In Form I and o -a2bBF 2 , smearing induces a transition from monomer-like to excimer-like emission, whereas Form II and m -a2bBF 2 retain excimer-like emission sites that are largely insensitive to mechanical perturbation. These findings demonstrate that both substitution position and crystal polymorphism critically govern MCL activity by modulating the balance between weak CH-pi and strong pi-pi intermolecular interactions.
Water is essential for human activities, yet most global water stress assessments treat water supply and demand separately, limiting representation of dynamic environment-society interactions. Water is essential for human activities; we developed a coupled IAM-LSM framework linking the global change analysis model (GCAM) and the Integrated Land Simulator (ILS) through land-use change. We conducted simulations under the SSP1-2.6 scenario for 2020-2100. We evaluated the impact of coupling by comparing simulated monthly river discharge climatology from ILS with observations from the Global Runoff Data Centre (GRDC). The coupled system reduced discharge biases and significantly improved the representation of river flow seasonality (global mean correlation increased from 0.30 to 0.31; p = 0.017), demonstrating a statistically significant though modest improvement in hydrological performance. Using a flexible method to quantify inter-sub-basin water transfers, we assessed water stress and population exposure at the geopolitical sub-basin scale defined by basins and political boundaries at both annual and seasonal scales. While annual and seasonal estimates of spatial distribution and population exposure broadly agreed with previous global studies, additional water-stress hotspots were identified in regions such as South Africa, Argentina, and southeastern Brazil. Our seasonal-scale assessment further revealed water stress and population exposure that are obscured by annual aggregation, reaffirming the importance of seasonal-scale water stress evaluation. Annual exposure to severe water stress reached 2.15 billion people in 2020, whereas seasonal assessment indicated that up to 67% of the global population experienced severe stress in at least one season. Moreover, despite a simplified representation, our estimation of non-surface water use showed strong agreement in global magnitude and spatial patterns with AQUASTAT data (R 2 = 0.91), indicating that aggregate groundwater and non-conventional water dependence can be approximated from surface water deficits without explicitly modeling individual components. Overall, the coupled IAM-LSM framework provides an internally consistent and scalable basis for assessing global water stress under interacting climatic and socioeconomic changes.
Although photoelectrochemical impedance spectroscopy (PEIS) has been widely used to analyze charge transport and transfer processes in such systems, conventional measurements under broadband illumination inherently average wavelength-dependent phenomena and obscure their individual contributions. In this study, we report the development of wavelength-dependent photoelectrochemical impedance spectroscopy, which extends the potential-dependent PEIS (pot-PEIS) by incorporating monochromatic illumination. This method enables systematic investigation of charge carrier-transport mechanisms as a function of excitation wavelength, providing insight into wavelength-dependent bulk electron transport, and interfacial hole-transfer processes. The technique was applied to hematite photoanodes fabricated using different preparation strategies, including TiO2 underlayers, alcohol-assisted deposition, and microwave-assisted calcination. The wavelength-selective pot-PEIS measurements revealed distinct impedance responses depending on the excitation wavelength and fabrication method, reflecting differences in charge carrier resistivity and defect state distributions with a two-dimensional map of the wavelength and potential. These results demonstrate that charge transport and recombination pathways in hematite are strongly influenced by the photocarrier generation region in the depth direction. The developed wavelength-dependent pot-PEIS provides a powerful and generally applicable platform for disentangling wavelength-and-potential-dependent charge transport phenomena and offers a mechanistic understanding of photoelectrochemical materials, which establishes a multidimensional analytical framework capable of generating state-sensitive electronic fingerprints of semiconductor photoelectrodes.
This study proposes a regression-based emotion estimation method by mapping postural features onto Russell's circumplex model using graph neural networks (GNNs). By extracting both geometric and structural features from skeletal coordinates and embedding them into a two-dimensional emotion space, we achieved visual and interpretable emotion representations. Numerical experiments on two public datasets (MASR and MEED) demonstrated that postural features, particularly those along the arousal axis, effectively reflect emotional states. Furthermore, mapping to a circular emotion space reveals that emotions like fear and sadness exhibit distinct postural patterns, whereas anger and happiness often overlap with surprise. These results suggest that our method enables a nuanced understanding of postural emotion expression and supports visual analysis of emotional similarities and distinctions.
