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Karhunen–Loève expansion of random measures
No full textWe present an orthogonal expansion for real, function-regulated, second-order random measures over ℝd with measure covariance. Such an expansion, which can be seen as a Karhunen– Loève decomposition, consists in a series of deterministic real measures weighted by uncorrelated real random variables with the variances forming a convergent series. The convergence of the series is in a mean-square sense stochastically and against measurable and bounded test functions (with compact support if the random measure is not finite) in the measure sense, which implies set-wise convergence. This is proven taking advantage of the extra requirement of having a covariance measure over ℝd × ℝd describing the covariance structure of the random measure, for which we also provide a series expansion. These results cover for instance the cases of Gaussian White Noise, Poisson and Cox point processes, and can be used to obtain expansions for trawl processes
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No full textContext. Galaxy clusters trace the densest regions of the cosmic web and are crucial laboratories for studying the thermodynamic and chemical evolution of the intracluster medium (ICM). The massive galaxy cluster SPT-CL J0217−5014 (z ∼ 0.53; M500 ∼ 3 × 1014 M⊙) is one of the Swift X-Ray Telescope serendipitous galaxy clusters with the highest reported Fe abundance (∼1.3 ± 0.4 Z⊙ within ) and a potentially disturbed morphology.
Aims. SPT-CL J0217−5014 presents an intriguing opportunity to investigate ICM chemical enrichment and cool-core survival. With this study, we aim to evaluate its chemical and thermodynamic properties with a dedicated Chandra observation.
Methods. Using new Chandra observations, we derived surface brightness profiles and dynamical state parameters. We also performed spectral fitting using different backgrounds to constrain the Fe abundance. We performed joint analysis of the X-ray surface brightness, temperature, and integrated Sunyaev-Zel’dovich Compton parameter to constrain the density profile. The DESI optical galaxy cluster catalogue was examined to explore its large-scale environment.
Results. The X-ray morphology reveals a disturbed ICM with a surface brightness edge at (∼100 kpc) to the west and a tail-like feature extending towards the east. The best-fit metal abundance within (∼0.7 R500) is Z⊙. The derived central electron number density, entropy, and cooling time classify this system as a non-cool-core cluster, suggesting that merger activity has likely disrupted the possible pre-existing cool core. At larger radii (∼1′−2′), we detected excess X-ray emission to the south spatially aligned with a filamentary distribution of red galaxies, indicating ongoing accretion along an intracluster filament. Based on the DESI DR9 cross-matched optical clusters and photometric redshifts, we identified three nearby lower-mass clusters that likely trace the large-scale structures, suggesting that SPT-CL J0217−5014 is the primary node of a dynamically active environment where past mergers and anisotropic accretion along cosmic filaments have shaped the present-day ICM
The richness of butterfly species and the discovery of a new record species (
No full textAyapokiar is village in a protected forest area with an altitude of 925 m above sea level. This area is rich in biodiversity, including that of butterflies. Although this area is a protected forest, there are no data on butterfly species in the area. Thus, this study aimed to examine the richness and abundance of butterfly species in protected forest areas, especially in Ayapokiar Village. Scanning sampling on a predetermined line transect was used. A total of 135 butterflies and 1540 individuals were successfully identified in six families (Papilionidae, Hesperidae, Pieridae, Riodinidae, Lycaenidae, and Nymphalidae). The results of the Shannon Wiener diversity index analysis showed high diversity, with a value of H '= 4.02. The study was conducted in primary forests, secondary forests, gardens, and residential habitat types. The highest diversity index of the four habitats was found in the primary forest habitat type, H'=3.87, and the lowest in the garden, H'=3.45. This study also identified Mycalesis Valeria, as a new species record. Previously, this species was found only in the Central and Cyclops Mountains. This indicates that there are similarities in plate formation between the Tambrauw, Central Mountains and Cyclops Mountains
The Potential Role of Shark Tourism in Raising Public Awareness for Conservation in Raja Ampat
No full textRaja Ampat is one of the world's leading marine tourism destinations, attracting visitors to experience high biodiversity, including sharks. Shark-based tourism is widely promoted as a tool for education and conservation; however, empirical evidence on changes in tourist knowledge and attitudes following interpretive shark-tour experiences in Indonesia remains limited. This study examines changes in tourist knowledge, attitudes, and experiences associated with shark-related tourism on Kri Island. Data were collected between August and October 2024 through interviews with 200 tourists using a mixed qualitative-quantitative approach. A pre-post questionnaire was applied and analysed using descriptive statistics to assess changes in knowledge and attitudes, supported by thematic analysis of interview responses. Our findings indicate that educational interpretation during shark tourism increased tourists' understanding of shark ecology and fostered more positive conservation-oriented attitudes. Many participants reported a willingness to engage in conservation actions, such as reporting shark sightings and supporting local conservation programs. These findings underscore the importance of incorporating structured educational components for shark tourism. Overall, interpretive shark-based tourism can contribute meaningfully to strengthening conservation awareness and support for shark protection in Raja Ampat
Groundwater Quality Analysis at Merauke IIb Prison, Merauke Regency, South Papua Province
No full textGroundwater resource that can be utilized by humans to meet their needs. A study on the potential distribution of groundwater was conducted at Merauke IIb Prison, Merauke Regency, South Papua Province using the 1D geoelectrical measurement method analysis of the Werner-Schlumberger configuration. The data acquisition was performed on two measurement paths. The length of the first path (GL-LPS1) was 300 m, with a spacing of 2.5 - 25 meters. The second path (GL-LPS2) is 180 m, with a spacing of 2.5 - 20 meters. The results showed that these two test wells contained brackish-salty water while one test well was fresh water. Based on the data analysis, the dominant resistivity value was <315 Ωm in both paths which was interpreted as clay, sand and gravel. Moreover, the distribution of aquifers on the first path was at a depth of 83.5-170 meters, while in path 2 the distribution of aquifers was at a depth of 90-110 meters. Thus, the analysis results indicated heterogeneity in the groundwater quality. Despite similar local lithologies, this indicates different water sources at each location. Therefore, water supply management must be considered in a prison environment
Seasonal Dynamics and Interconnected Physico-Chemical and Biological Water Quality Parameters in the Muari River, West Papua Province, Indonesia
No full textUnderstanding seasonal dynamics in tropical rivers is crucial to link land use, geomorphology, and ecosystem health. This study examined the seasonal dynamics and interconnections among physico-chemical, sediment, and biological parameters in the Muari River, West Papua, Indonesia. Water quality indicators-including total dissolved solids (TDS), total suspended solids (TSS), conductivity, 5-day biochemical oxygen demand (BODs), chemical oxygen demand (COD), dissolved oxygen (DO), phosphate, nitrate, and total coliform-were measured at three sites (upstream, midstream, and downstream) during the dry (July) and rainy (August) seasons in 2022. Analyses followed Indonesian National Standards (SNI) using calibrated instruments and KAN-accredited laboratory testing. Descriptive statistics and Pearson correlation analyses were employed to assess spatial and temporal variability. Results showed moderate seasonal differences, with elevated TDS, TSS, and total coliform during the rainy season, while DO, BODs, and COD remained stable. Strong positive correlations between TDS and conductivity (r = 0.87) and between TDS and TSS (r = 0.88) indicated runoff-driven transport. Conversely, COD correlated negatively with TDS (r = -0.72) and TSS (r = -0.76), suggesting dilution during high discharge. These findings underscore the necessity of integrated management strategies to sustain tropical river health
Climatology and spectral characteristics of 10-day rainfall variability in Manokwari, West Papua (1991–2022)
No full textRainfall variability in the Indo-Pacific warm pool arises from coupled interactions between the Intertropical Convergence Zone (ITCZ), the Asian-Australian monsoon, and large-scale ocean-atmosphere teleconnections. However, eastern Indonesia, particularly West Papua, remains underrepresented in climatological research. This study examined rainfall dynamics in Manokwari, West Papua, using 32 years (1991-2022) of BMKG station observations. Daily rainfall was aggregated into dekadal (10-day) totals to capture variability from intraseasonal to interannual timescales. We first characterized the annual and seasonal rainfall cycles using descriptive statistics and then diagnosed the dominant periodicities through Fast Fourier Transform (FFT) spectral analysis. To assess large-scale climate control, we quantified relationships between dekadal rainfall and key climate drivers, El Nino-Southern Oscillation (ENSO), the Indian Ocean Dipole (IOD), and the Australian monsoon, using correlation and partial correlation analyses to isolate each driver's independent association amid overlapping signals. Together, these diagnostics establish a robust dekadal climatology for an equatorial maritime region with limited prior analysis, supporting seasonal monitoring and climate-sensitive decision making. Beyond site-specific findings, this study introduces a replicable central-local co-production approach: standardized diagnostics developed centrally are paired with locally owned station data and locally contextualized interpretation by forecasters in the field. Applied across stations, this framework can strengthen the local analytical capacity in remote regions while improving the consistency and depth of Indonesia's climate information services for adaptation and operational forecasting, with ENSO emerging as the most robust large-scale modulator in both partial-correlation and phase-composite evidence
Groundwater Resource Potential in Table Mountain Forest, Manokwari, West Papua: A Hydrogeological Review for Conservation
No full textThis study evaluates the groundwater resource potential in Table Mountain Forest, Manokwari, West Papua, through comprehensive hydrogeological analysis for conservation planning. The 462-hectare protected forest area contains 44 active springs within a karst aquifer system that supplies 10.30% of Manokwari's municipal water demand. Using a systematic literature review methodology integrating geological, climatological, and ecological data from 2015 to 2024, this research employed multi-criteria analysis weighting geological factors (40%), climatological conditions (30%), topographical features (20%), vegetation cover (10%) and geoelectric surveys to assess groundwater potential. The application of the multi-criteria analysis framework produced a groundwater potential map of Table Mount as a high potential area zone. The geoelectric surveys identified shallow unconfined aquifers at 0.854-4.36 m depth with optimal conditions in survey lines 1, 2, and 5. The bedrock typically begins at a depth of approximately 6-9 m with resistivity values exceeding 13,000 flm, indicating an impermeable basement rock that prevents deeper groundwater circulation. However, developmental pressures present significant conservation challenges. The study recommends ecosystem-based management with three conservation zones: core (300 ha), buffer (100 ha), and transition (62 ha), alongside monitoring networks, 50-meter spring protection buffers, and climate adaptation strategies
Nouvelle ère d’observation en cosmologie avec les relevés DESI et Euclid
No full textLa cosmologie a vécu une véritable révolution en 1998 avec la découverte de l’accélération de l’expansion de l’Univers. Impossible dans un Univers composé uniquement de matière et de rayonnements, cette accélération nécessite une nouvelle composante, baptisée énergie noire.
De nombreux projets ont vu le jour dans l’objectif de caractériser cette mystérieuse énergie noire au moyen de grands relevés spectroscopiques de galaxies, comme le projet au sol DESI (Dark Energy Spectroscopic Instrument) et la mission spatiale Euclid. Par des approches différentes mais complémentaires, ces deux expériences devraient apporter des résultats cruciaux sur l’évolution de l’Univers et la nature de ses constituants