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Efficient Markerless Motion Classification Using Radar
No full textHighlights What are the main findings? A novel markerless motion-classification method that uses radar micro-Doppler features achieves nearly 100% classification accuracy with a compact feature set. The method uses cross-correlation between radar signals and basis functions derived from 3D motion-capture data, then applies PCA dimensionality reduction and nearest-neighbor classification. What is the implication of the main finding? The proposed method enables accurate classification of human motion without markers, and thereby ensures privacy and reduces the cost compared to traditional motion-capture systems. The approach is accurate across varying SNR conditions, and is therefore suitable for real-world applications such as healthcare monitoring and sports analytics.Highlights What are the main findings? A novel markerless motion-classification method that uses radar micro-Doppler features achieves nearly 100% classification accuracy with a compact feature set. The method uses cross-correlation between radar signals and basis functions derived from 3D motion-capture data, then applies PCA dimensionality reduction and nearest-neighbor classification. What is the implication of the main finding? The proposed method enables accurate classification of human motion without markers, and thereby ensures privacy and reduces the cost compared to traditional motion-capture systems. The approach is accurate across varying SNR conditions, and is therefore suitable for real-world applications such as healthcare monitoring and sports analytics.Abstract This study proposes a novel method that uses radar for markerless motion classification by using effective features derived from micro-Doppler signals. The training phase uses three-dimensional marker coordinates captured by a motion-capture system to construct basis functions, which enable modeling of micro-motions of the human body. During the testing phase, motion classification is performed without markers, relying solely on radar signals. The feature vectors are generated by applying cross-correlation between the received radar signal and the basis functions, then compressed using principal component analysis, and classified using a simple nearest-neighbor algorithm. The proposed method achieves nearly 100% classification accuracy with a compact feature set and is accurate even at high signal-to-noise ratios. Experimental results demonstrate that to optimize training data and increase computational efficiency, the sampling duration and sampling interval must be set appropriately.11Nsciescopu
New Pyrrole Derivatives from the Marine-Derived Streptomyces xiamenensis 1310KO-148 and Their Anti-inflammatory Activity
No full textNew pyrrole derivatives (1–6) were isolated from the marine-derived Streptomyces xiamenensis 1310KO-148, which was obtained from a sponge sample. The structures of 1–6 were elucidated by comprehensive analyses of 1D, 2D NMR, and HRESIMS data. The absolute configurations of 2-4 and 6 were determined by comparison of their calculated and experimental electronic circular dichroism (ECD) spectra. Notably, the position of the hydroxamate group in 6 was confirmed through NO-methylation and the analysis of NOESY correlations. The isolated compounds (1–6) were tested for their anti-inflammatory effects in LPS-stimulated RAW 264.7 cells, a mouse macrophage cell line. Treatment of RAW 264.7 cells with 30 μM of 1–6 exhibited no significant cytotoxic effects. Among them, only 1 dose-dependently suppressed LPS-induced production of NO (IC₅₀ = 29.5 μM) and interleukin-6 (IL-6) (IC₅₀ = 10.9 μM).1
Discovery of Bioactive Secondary Metabolites from Streptomyces albogriseolus Isolated from a Marine Sediment Sample Taken near Dokdo Island
No full textMarine derived microorganisms are a promising source of novel bioactive compounds with pharmaceutical potential. In our ongoing study on the discovery of bioactive secondary metabolites from marine microorganisms, Streptomyces albogriseolus was isolated from a marine sediment sample collected near Dokdo, Republic of Korea. According to a preliminary antibacterial test, its crude extract exhibited potent activity. To isolate the active components, the strain was cultured in a 10L fermentation system, and the extract was subjected to chromatographic purification. As a result, the major antibacterial compounds were identified by detailed analysis of NMR and MS data as Virginiamycins M1 and M2, which were originally discovered in the terrestrial species Streptomyces virginiae.
S. albogriseolus is a relatively underexplored species, and our findings demonstrate that rare marine actinomycetes can produce pharmacologically important metabolites. This study highlights the untapped potential of marine microorganisms in drug discovery and underscores the importance of exploring unique environments such as Dokdo for novel bioresources.1
New Record of Two Marine Scuticociliates (Protozoa, Ciliophora) Isolated from Infected Fishes in South Korea
No full textDuring a field survey of parasitic ciliate diversity in South Korea, we collected two scuticociliates-Mesanophrys carcini (Grolière and Leglise, 1977) Small and Lynn in Aescht, 2001 and Paralembus digitiformis (Kahl, 1931) Jankowski, 2007-from infected fishes. The pathological characteristics and molecular sequences of these populations have been published previously; in this study, we provide detailed morphological diagnoses since both genera/species are newly recorded in Korea. Morphological identification was based on live observations and silver-impregnated preparations, using protargol ‘A’ and Chatton-Lwoff silver nitrate techniques. Brief comparisons with closely related species are also provided. Morphological characteristics of M. carcini: body size about 28×11 μm; body slender, oval, slightly asymmetrical; anterior end pointed; 1 macronucleus, 1 micronucleus; 10 somatic kineties, bipolar; kineties 1 and 10 with 27-30 and 27-32 mono/dikinetids, respectively; scutica composed of 4 or 5 mono/dikinetids; oral apparatus with 3 adoral membranelles and paroral membrane; adoral membranelles 1-3 with 2, 4, and 2 basal body rows, respectively (after silver impregnation). Morphological characteristics of P. digitiformis: body size about 42×22 μm; body slender, oval; anterior end pointed; 1 macronucleus, 1 micronucleus; 20 or 21 somatic kineties, bipolar; kineties 1 and n with 34-42 and 35-49 mono/dikinetids, respectively; scutica composed of 9-15 mono/dikinetids; oral apparatus with 3 adoral membranelles and paroral membrane; adoral membranelles 1-3 with 2, 4, and 3 basal body rows, respectively (after silver impregnation).22Ykc
Intensifying Summer Drying Patterns across East Asia: Distinct Mechanisms between Southeastern China and the Yellow Sea Region
No full textEast Asia has experienced significant changes in its traditional warm and humid summer climate over recent decades. This study investigates the intensifying drying trends across the region during the extended summer season (April-September) from 1980 to 2022, focusing on regional characteristics and their driving mechanisms. Using ERA5 reanalysis and KORS in-situ data, we identify widespread drying across East Asia's land and sea areas, with notable trends in southeastern China, the Yellow Sea, and parts of the Korean Peninsula. Moisture budget analysis and CAM6 model experiments reveal distinct regional processes that contribute to these drying patterns. In southeastern China, the drying trend is primarily driven by dynamic processes, characterized by enhanced moisture divergence and anomalous descending motion. These dynamic changes are closely linked to the warming of the Indo-Pacific warm pool, influenced by both anthropogenic warming and Pacific Decadal Oscillation-like sea surface temperature patterns. In contrast, the Yellow Sea region's drying is dominated by thermodynamic processes through modified moisture transport patterns. Global warming has led to higher sea surface temperatures and humidity over the Northwest Pacific marginal seas, while inland China shows relatively lower humidity. This altered humidity distribution, combined with prevailing southwesterly winds, facilitates the transport of drier continental air into the Yellow Sea region. Our findings demonstrate that East Asia is facing widespread summer drying and the underlying mechanisms vary significantly between land and sea areas, providing new insights into regional climate variability in the context of global climate change.1
Monitoring LULC Change in a Freshwater Swamp Forest of Bangladesh: A Remote Sensing-Based Interpretation of Conservation Policy Outcomes
No full textRatargul swamp forest (RSF), is the largest freshwater swamp forest of Bangladesh, plays a critical role as a habitat for both various terrestrial and aquatic species. Despite its ecological importance, research addressing recent changes in land use and land cover (LULC) within RSF remains limited. Recognizing this gap, this study examines LULC changes in RSF, particularly considering its designation as a ‘Special Biodiversity Protected Area’ in 2015. Remote sensing techniques were utilized, and two complementary vegetation indices—the normalized difference vegetation index (NDVI), which captures vegetation greenness, and the enhanced vegetation index (EVI), which corrects for atmospheric and canopy background effects—were applied to Landsat-8 satellite data collected from January 2014–2020. A maximum likelihood supervised classification was subsequently performed to categorize the landscape into four LULC classes: forest, sparse vegetation, bare land, and water. These classifications were analyzed via postclassification change detection to track shifts over time. The results indicated significant LULC transformations, with forest cover increasing by 1.07% and sparse vegetation decreasing by 6.04% between 2014 and 2020, on the basis of the NDVI-derived classifications. EVI-based classifications displayed similar trends, with a 4% higher overall accuracy. Peaks in sparse vegetation and forest areas were noted in 2014 and 2016, respectively, with distinct transitions observed among forest, sparse vegetation, bare land, and water areas. These findings highlight notable ecological changes coinciding with RSF’s recent conservation status, suggesting potential alignment with management goals. However, these results reflect associations rather than direct causal effects.33Nscopu
A Study on the Coastline Extraction and Coastal Change Analysis Using Sentinel-2 Imagery in Funafuti, Tuvalu
No full textTemporal alterations in coastlines depict the significant changes in coastal areas, driven by both natural processes and human activities. For island nations, monitoring of the coastline is essential due to their vulnerability to such impacts. In this study, Funafuti Atoll, an archipelago of small and scattered islands around the capital of Tuvalu, is selected as the study region, and the aim is to extract coastlines of different islands and investigate coastal area changes between 2019 and 2023 using Sentinel-2 imagery. A simple linear iterative clustering-based superpixel segmentation and adaptive thresholding approach is employed for coastline extraction. Initially, superpixel segmentation is conducted to cluster 3-band image pixels into coherent regions, excluding the sea area. Subsequently, the normalized difference vegetation index (NDVI) is calculated, and the superpixels are used to obtain corresponding NDVI regions, on which adaptive Gaussian thresholding is applied to extract coastlines. Finally, the areas enclosed by the extracted coastline boundaries are utilized for change analysis. The results indicate that islands along the western rim of Funafuti exhibited significant alteration (an average decrease of −14.48%), whereas those along the eastern rim remained relatively stable due to the presence of coral rubble ridges and steep slopes. The change analysis revealed that from 2019 to 2020, approximately 15.1 hectares (ha) were eroded, resulting in a net area change rate of −4.14%. Between 2020 and 2021, erosion increased to 20.2 ha, yielding a net change of −7.75%. From 2021 to 2022, 13.2 ha were eroded, corresponding to a −1.74% change. From 2022 to 2023, a net gain of 10.3 ha occurred (+0.25%), primarily due to land reclamation along the lagoon-facing coast of Fongafale Island. Overall, all islands showed a decreasing area trend between 2019 and 2023, with an average net change of −12.97%. The coastal changes occurred along the sand-dominated coast with gentle slopes, possibly driven by the impact of tropical cyclones, prolonged swells, and coastal flooding, which act as the primary driving forces for the study region.11Ysciescopu
Characterization of ship paint-derived microplastics by Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray spectroscopy (EDS), and density analyses
No full textThis study presents a comprehensive characterization of ship paint-derived microplastics by integrating Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray spectroscopy (EDS), and density analysis. FTIR identified characteristic absorption peaks in the fingerprint region (1500–600 cm⁻¹) across six paint types: acrylate, rosin, polydimethylsiloxane, epoxy, urethane, and alkyd. While four paint types showed high spectral match with their original polymers, acrylate- and rosin-based types, exhibited significant spectral similarity with alkyd- and urethane-based polymers, suggesting potential misclassification when relying solely on spectral libraries. EDS revealed the presence of elements including C, O, Mg, Si, S, Cl, Ca, Ti, Fe, Cu, Zn, and Ba in varying proportions, reflecting the compositions of pigments and biocidal additives. Density of the particles ranged from 1.177 to 2.615 g/cm³ , with high-density antifouling particles exceeding conventional microplastic separation thresholds (∼1.6 g/cm³), thereby increasing the likelihood of their underestimation in environmental monitoring. The combined use of FTIR spectral interpretation, elemental analysis, and density profiling offers a robust approach for distinguishing paint-microplastics from other microplastic types and provides critical reference data for improved identification and quantification. These findings underscore the need to refine current analytical methods to more accurately evaluate the contribution of paint particles to marine microplastic pollution.11Nsciescopu