Search Results (42)

Urban energy infrastructure in dense metropolitan regions must decarbonize essential public services while avoiding additional land take and excessive costs. This study presents a techno-economic and sustainability assessment of a grid-connected hybrid wind–solar street-lighting microgrid, created by retrofitting an existing nine-node off-grid installation at Odaiba Beach, Tokyo Bay, into an embedded distributed generation asset. The design departs from complementary sizing by independently scaling PV and wind so that each source can satisfy worst-case winter lighting demand, enabling both a reduction in battery autonomy from five to two days and the deliberate use of seasonal surpluses for grid export. Steady-state load-flow analysis in ETAP indicates annual generation of 1803.73 kWh from PV and 1192.54 kWh from wind, corresponding to approximately 1.84 MWh/year of net clean energy export after supplying 1009.15 kWh/year of lighting demand and incurring 149.09 kWh/year of distribution losses, with voltages compliant with industry standards. Sensitivity analysis under conservative solar and wind scenarios shows that the system remains export-positive in all cases, thereby supporting sustainable urban development by decarbonizing street-lighting, improving land-use efficiency through infrastructure co-location, and providing a replicable framework for similar coastal cities. Full article

Reduced mud in the Yoro tidal flat (inner part of Tokyo Bay, Japan) consists of black and highly viscous sediment containing high levels of polycyclic aromatic hydrocarbons (PAHs). The mud is formed through the decomposition of terrestrial plants washed up on the tidal flat; however, the origin of PAHs within the mud has remained unclear. To investigate the origin of PAHs in the mud, we analyzed PAHs in the mud and fragments of terrestrial plants using gas chromatography–mass spectrometry. The total PAH concentrations except for perylene were comparable between the mud (336 ± 58 μg kg-dry⁻¹) and the fragments of plants (247 ± 77–435 ± 235 μg kg-dry⁻¹), and their compositional patterns were also similar. These results indicate that the high levels of PAHs in the mud primarily originated from the fragments of plants that composed the mud. Furthermore, the perylene (Pery) concentrations in the fragments of plants were the same as or higher than those in the mud, suggesting that the formation of Pery begins in the plant tissues even before the mud was formed. These findings reveal a previously unrecognized pathway by which terrestrial plants introduce PAHs into tidal flat environments. Full article

Knowledge about vessel activity in port areas and around major industrial zones provides insights into economic trends, supports decision-making for shipping and port operators, and contributes to maritime safety. Vessel data from terrestrial receivers of the Automatic Identification System (AIS) have become increasingly openly available, and we demonstrate that such data can be used to infer port activities at high resolution and with precision comparable to official statistics. We analyze open-access AIS data from a three-month period in 2024 for Tokyo Bay, located in Japan’s most densely populated urban region. Accounting for uneven data coverage, we reconstruct vessel activity in Tokyo Bay at ~30 m resolution and identify 161 active berths across seven major port areas in the bay. During the analysis period, we find an average of $35\pm {17}_{\mathrm{stat}}$ vessels moving within the bay at any given time, and $293\pm {22}_{\mathrm{stat}}+{65}_{\mathrm{syst}}-{10}_{\mathrm{syst}}$ vessels entering or leaving the bay daily, with an average gross tonnage of ${\mathrm{11,860}}_{-50}^{+280}$. These figures indicate an accelerating long-term trend toward fewer but larger vessels in Tokyo Bay’s commercial traffic. Furthermore, we find that in dense urban environments, radio shadows in vessel AIS data can reveal the precise locations of inherently passive receiver stations. Full article

Classifying optical water types (OWTs), particularly concerning different phytoplankton bloom types, is critically important because dominant phytoplankton groups govern key marine ecosystem functions and biogeochemical processes, including nutrient cycling and carbon export. This study refines a recent OWT classification method developed for the Second-Generation Global Imager (SGLI), which was originally proposed to discriminate dinoflagellate and diatom blooms. By employing binary logistic regression (bLR) with independent in situ data from Karenia selliformis (dinoflagellate) blooms off the Kamchatka Peninsula and Skeletonema spp. (diatom) blooms in Tokyo Bay, this study establishes more robust and statistically meaningful boundaries between OWTs. The analysis confirms the diagnostic spectral shapes from SGLI data: a trough at 490 nm for K. selliformis blooms and a peak at 490 nm for diatom blooms, validating the consistency of this spectral criterion. The updated method reliably identifies waters dominated by coloured dissolved organic matter and different phytoplankton functional types in mesotrophic waters, and successfully detected a Karenia mikimotoi bloom in the Gulf St. Vincent, South Australia, demonstrating its potential for the global monitoring of red tides. By providing a reliable, satellite-based tool to distinguish between ecologically distinct phytoplankton groups, this refined OWT classification offers a valuable data product to improve the accuracy of marine ecosystem and carbon cycle models, moving beyond bulk chlorophyll-a parameterizations. Full article

Urban estuarine environments face increasing water safety risks due to microbial contamination from combined sewer overflows (CSOs), particularly during heavy rainfall events. In megacities like Tokyo, where waterfronts are widely used for recreation, such contamination poses significant public health risks. The challenge is compounded by the variability in both intensity and spatial distribution of rainfall across the catchment, combined with complex tidal dynamics making effective water quality management difficult. To address this challenge, we conducted a series of hydrodynamic–microbial fate simulations to examine the spatial and vertical behavior of Escherichia coli (E. coli) under different rainfall–tide conditions. Focusing on the Sumida River estuary, rainfall data from eight drainage areas were classified into six event types using cluster analysis. Two contrasting events were selected for detailed analysis: a light rainfall (G2, 15 mm over 13 h) and an intense event (G6, 272 mm over 34 h). Vertical water quality profiling was performed along an 8.5 km transect from the Kanda–Sumida River confluence to the Tokyo Bay Tunnel, illustrating E. coli and salinity. The results showed that the rainfall intensity and tidal phase at the event onset are critical in shaping both the magnitude and vertical distribution of microbial contamination. The intense event (G6) led to deep microbial intrusion (up to 6–7 m) and major salinity disruption, while the lighter event (G2) showed surface-layer confinement. Salinity gradients were more strongly affected during G6, indicating freshwater intrusion. Tidal phase also influenced transport: the flood-high condition retained E. coli, whereas ebb-low tides facilitated downstream flushing. These findings highlight the influence of rainfall intensity and tidal timing on microbial distribution and support the use of vertical profiling in estuarine water quality management. They also support the development of dynamic, event-based water quality risk assessment tools. With appropriate local calibration, the modeling framework is transferable to other urban estuarine systems to support proactive and adaptive water quality management. Full article

Understanding the hierarchical patterns of building heights is essential for sustainable urban development and planning. This study presents a novel approach for detecting and comparing building height hierarchies in four major bay areas: the San Francisco Bay Area, the New York Bay Area in the United States, the Tokyo Bay Area in Japan, and the Guangdong-Hong Kong-Macau Greater Bay Area in China. Kernel density estimation was first used to create continuous spatial distributions of building heights, forming the basis for our analysis. The approach then uses the contour tree algorithm to abstract and visualize these hierarchies. A structural similarity index is proposed to compare the hierarchies by identifying the maximum common sub-contour tree across the different contour trees. The results reveal that all four bay areas exhibit a multi-core hierarchical structure, with the greater bay area exhibiting the most complex pattern. Quantitative comparison reveals that the building height hierarchies of the New York Bay Area and Tokyo Bay Area are most similar (similarity index = 0.74), while those of the San Francisco Bay Area and Greater Bay Area are the least similar (similarity index = 0.17). Our approach provides a practical tool for understanding building height hierarchies and can be readily applied to analyze diverse spatial patterns. Full article

Tokyo Bay is one of the busiest ocean areas for human activity worldwide, characterized by a high density of maritime traffic and industrial development. This area is also recognized as the habitat of the narrow-ridged finless porpoise, an endangered toothed whale. Although the existence of this species has been recognized, its scientific data, such as population size and geographic distribution, are limited in the region. Therefore, using social media, we initiated a research project to collect sighting information on this species in Tokyo Bay. As a result, 27 valid pieces of information on the finless porpoises were collected from July 2024 to the end of February 2025. The sightings were reported mainly in the waters north of Futtsu Cape, indicating that this species is localized in the northern part of Tokyo Bay. Also, most of the reported sightings were of groups of wo or more animals. Notably, a school of at least 30 animals was recorded, marking the most prominent school ever observed in the region and the third largest in Japan. This study highlights the importance of the northern region of Tokyo Bay as a habitat for this species. The effective integration of citizen science with scientific and quantitative research will enhance our understanding of the life history of this endangered species, thereby supporting conservation efforts. Full article

This narrative review examines the issue of sleep deprivation among children and adolescents in Japan, exploring its cultural origins and evaluating the current state of sleep education and interventions. It emphasizes the profound influence of the Bushidō spirit, with its focus on self-sacrifice and asceticism, as a core factor in the undervaluation of sleep in Japanese society. While educational initiatives and interventions highlighting the importance of sleep exist, significant limitations remain in improving sleep habits. Sleep deprivation continues to affect children and adolescents, despite its considerable impact on mental health and academic performance. This review presents a method for personalized sleep duration estimation and assesses its potential impact on improving sleep health by using optimal sleep duration calculations. The review also proposes practical steps to improve sleep duration through individualized strategies, integrating cultural context to mitigate the serious health risks associated with insufficient sleep. Ultimately, it underscores the need for targeted strategies to improve sleep among children and adolescents—particularly through personalized optimal sleep duration estimation—while advocating for a shift in cultural perspective beyond self-sacrifice and asceticism. The review highlights the importance of cultural transformation and suggests future research directions and practical applications. Full article

A new oxylipin (1) was isolated from cyanobacteria collected at Tokyo Bay, Japan. The structure of 1 was elucidated based on spectroscopic data including 1D and 2D NMR, as well as high-resolution mass spectrometry. The structure of 1 was elucidated to be (S)-2-hydroxy-3-(((2R,3R,4S,5R,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)tetrahydro-2H-pyran-2-yl)oxy)propyl (E)-8-hydroperoxyhexadec-6-enoate. Full article

The coastal regions of major bay areas—including San Francisco, Tokyo, New York, Guangdong–Hong Kong–Macao, and Hangzhou—are important centers of economic and social growth due to their strategic location, resources, and dynamic economies. However, the significant development disparities between the central cities and surrounding areas, as well as the challenges of climate change, highlight the need for a comprehensive assessment of their development potential. The aim of this study is to find out which cities have the strongest development potential and what the main factors influencing the results are. To address this research question, we use a combination of the Analytic Hierarchy Process (AHP) and the Entropy Weight Method (EWM) to systematically assess the development potential of 63 cities in five bay area regions and explore the mechanisms that influence it. The principal component analysis (PCA) also examines the global networking and sustainability mechanisms. The results show that Shenzhen and Shanghai lead in development potential due to strong institutional frameworks and global connectivity, but significant imbalances remain in the bay areas. Key contributors to sustainability and connectivity include air passenger traffic, public libraries, and port handling, while traditional economic metrics such as GDP growth show limited impact. These findings underscore the importance of prioritizing urban livability, resource circulation, and infrastructure over traditional economic indicators for sustainability and provide actionable insights for policy makers to promote balanced and sustainable development in bay area cities. Full article

Abscess-forming cervical bacterial infections are rare and serious infections. Methods: We retrospectively examined the trends in abscess-forming cervical bacterial infections in children who required inpatient treatment in three periods before (January 2016 to June 2020), during (July 2020 to December 2022) and after the COVID-19 pandemic (January 2023 to June 2024). Results: The study included 96 patients with superficial cervical abscesses and 111 patients with deep cervical abscesses (34 with retropharyngeal abscesses, 51 with peritonsillar abscesses, and 26 with deep neck abscesses). Both decreased during the COVID-19 pandemic and increased significantly after the COVID-19 pandemic compared to before the COVID-19 pandemic (0.94 ± 0.92 vs. 0.50 ± 0.72 vs. 1.67 ± 1.11/month, 0.93 ± 0.96 vs. 0.60 ± 0.84 vs. 2.39 ± 1.70/month), which was related with the trends of respiratory viral infections. Bacteria were identified in 79 of the 97 cases in which punctures were performed; however, there were no significant differences between the three periods. No significant changes were found in the pharyngeal streptococcal antigen positivity rate, rate of oral antibiotic use before hospitalization, length of hospital stay, or duration of antibiotic administration before and after the COVID-19 pandemic. Conclusions: The COVID-19 pandemic has affected the epidemiology of cervical abscess-forming bacterial infections in children. Although the reemergence of respiratory viral infections after the COVID-19 pandemic may be a factor, the cause of the doubling in the number of neck abscesses after the COVID-19 pandemic remains unclear and requires further investigation. Full article

This study identifies the characteristics of water regions with negative normalized water-leaving radiance ($n{L}_w\left(\lambda \right)$) values in the satellite observations of the Second-generation Global Imager (SGLI) sensor aboard the Global Change Observation Mission–Climate (GCOM-C) satellite. SGLI Level-2 data, along with atmospheric and in-water optical properties measured by the sun photometers in the AErosol RObotic NETwork-Ocean Color (AERONET-OC) from 26 sites globally, are utilized in this study. The focus is particularly on Tokyo Bay and the Ariake Sea, semi-enclosed water regions in Japan where previous research has pointed out the occurrence of negative $n{L}_w\left(\lambda \right)$ values due to atmospheric correction with SGLI. The study examines the temporal changes in atmospheric and in-water optical properties in these two regions, and identifies the characteristics of regions prone to negative $n{L}_w\left(\lambda \right)$ values due to atmospheric correction by comparing the optical properties of these regions with those of 24 other AERONET-OC sites. The time series results of $n{L}_w\left(\lambda \right)$ and the single-scattering albedo ($\mathsf{\omega }\left(\lambda \right)$) obtained by the sun photometers at the two sites in Tokyo Bay and Ariake Sea, along with SGLI $n{L}_w\left(\lambda \right)$, indicate the occurrence of negative values in SGLI $n{L}_w\left(\lambda \right)$ in blue band regions, which are mainly attributed to the inflow of absorptive aerosols. However, these negative values are not entirely explained by $\mathsf{\omega }\left(\lambda \right)$ at 443 nm alone. Additionally, a comparison of in situ $n{L}_w\left(\lambda \right)$ measurements in Tokyo Bay and the Ariake Sea with $n{L}_w\left(\lambda \right)$ values obtained from 24 other AERONET-OC sites, as well as the inherent optical properties (IOPs) estimated through the Quasi-Analytical Algorithm version 5 (QAA_v5), identified five sites—Gulf of Riga, Long Island Sound, Lake Vanern, the Tokyo Bay, and Ariake Sea—as regions where negative $n{L}_w\left(\lambda \right)$ values are more likely to occur. These regions also tend to have lower $n{L}_w\left(\lambda \right)$ values at shorter wavelengths. Furthermore, relatively high light absorption by phytoplankton and colored dissolved organic matter, plus non-algal particles, was confirmed in these regions. This occurs because atmospheric correction processing excessively subtracts aerosol light scattering due to the influence of aerosol absorption, increasing the probability of the occurrence of negative $n{L}_w\left(\lambda \right)$ values. Based on the analysis of atmospheric and in-water optical measurements derived from AERONET-OC in this study, it was found that negative $n{L}_w\left(\lambda \right)$ values due to atmospheric correction are more likely to occur in water regions characterized by both the presence of absorptive aerosols in the atmosphere and high light absorption by in-water substances. Full article

A significant number of adolescents experience sleepiness, primarily due to sleep deprivation. The detrimental effects of inadequate sleep on both physical and mental health are well documented, particularly during adolescence—a critical developmental stage that has far-reaching implications for later life outcomes. The International Classification of Diseases 11th Revision recently introduced the disorder termed ‘insufficient sleep syndrome,’ characterized by a persistent reduction in sleep quantity. However, diagnosing this condition based solely on sleep duration is challenging due to significant individual variation in what constitutes optimal sleep. Despite this, managing sleep debt remains difficult without a clear understanding of individual optimal sleep needs. This review aims to reassess recommended sleep durations, with a focus on enhancing sleep literacy. Beginning with an exploration of insufficient sleep syndrome, this review delves into research on optimal sleep duration and examines foundational studies on sleep debt’s impact on the developing brain. Finally, it addresses the challenges inherent in sleep education programs from the perspective of sleep literacy. By doing so, this review seeks to contribute to a deeper understanding of the chronic sleep debt issues faced by adolescents, particularly those affected by insufficient sleep syndrome. Full article

Pleuroparenchymal fibroelastosis (PPFE) is characterized by fibrosis involving the pleura and subpleural lung parenchyma, predominantly in the upper lobes. As PPFE appears to occur in patients with heterogeneous etiologies, the disease course is thus also heterogenous, with some patients showing rapid progression while others have slow progression. Therefore, it is very difficult to predict prognosis with PPFE. Needless to say, this problematic matter has influenced the treatment strategy of PPFE patients. In fact, until now no evidence has been shown for use in creating an appropriate management algorithm for PPFE. We speculate that “uncoordinated breathing” is the most important reason for dyspnea in PPFE patients. Because monitoring of physique and not just pulmonary function and radiological evaluation is also very important, particularly in PPFE patients, this review focused on the characteristics of PPFE through an overview of previous studies in this field, and we proposed an algorithm as precision medicine based on the current evidence. Multiple views by the pulmonologist are needed to standardize a clinical algorithm that is necessary to correctly assess PPFE patients under the premise of maintenance of physique by providing appropriate nutritional care and pulmonary rehabilitation. Full article