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No full textAims. We investigate the formation and evolutionary trajectory of the Milky Way’s inner and outer galactic regions using stars from open clusters in the Gaia-ESO OC survey.
Methods. Using numerical simulations from Chempy, we leveraged Markov chain Monte Carlo sampling techniques to derive galactic evolutionary parameters for each open cluster by fitting measured abundances of elements C, N, O, Mg, Si, Ca, Ti, Fe, Mn, Zn, Y, and Ba.
Results. We find differing evolutionary histories between the inner and outer regions of the Milky Way that align with variations in the slope of the initial mass function, the rate of Type Ia supernovae, and the galactic metallicity gradient traced by open clusters.
Conclusions. Our results support established galactic formation and evolutionary theories, highlighting that the inner Galaxy had a short and intense early star formation epoch followed by reduced activity. In contrast, the outer Galaxy maintained a more sustained star formation history
Substellar population of the young massive cluster RCW 36 in Vela
No full textContext. The shape of the initial mass function (IMF) remains a fundamental yet contentious topic in the study of stellar formation and evolution. It is imperative to understand the potential variability of the IMF across different young regions. This study examines the IMF within the young massive cluster RCW 36 situated in the Vela Molecular Ridge, comparable with the Orion Nebula Cluster in terms of stellar surface density.
Aims. The primary objective of this research is to construct the most comprehensive census of the stellar population in RCW 36 to date and determine the first ever IMF and star to brown dwarf (BD) ratio for the cluster.
Methods. We used state-of-the art observational techniques, drawing on new GLAO observations conducted with HAWK-I/VLT in addition to archival data from 2MASS, SOFI/NTT, and new kinematics from Gaia DR3. To enhance photometric accuracy and source extraction, we employed D
Study on the luminescence enhancement of NaLaMgWO
No full textEu3+ doped NaLaMgWO6 red phosphors were prepared by solid state sintering method. The electronic structures of the phosphors are evaluated through density functional theory calculation. The band structure and density of states are studied. Y3+ or Lu3+ ions were adopted to enhance the luminescence properties of the red phosphors. When excited at 465 nm, these phosphors present strong red emission at 618 nm. The octahedral distortion leads to the improvement of the luminescence performance of the NaLaMgWO6: Eu3+ phosphors. The photoluminescence intensity at 150 °C is 77% of that at room temperature. The chromaticity coordinates of prepared phosphors are in the red region and near the standard value for red color. These results indicate that this series of tungstate phosphors can serve as a potential red emitting material for lighting devices
Probing jet base emission of M87* with the 2021 Event Horizon Telescope observations
No full textWe investigate the presence and spatial characteristics of the jet base emission in M87* at 230 GHz, enabled by the significantly enhanced (u,v) coverage in the 2021 Event Horizon Telescope (EHT) observations. The integration of the 12−m Kitt Peak Telescope (USA) and NOEMA (France) stations into the array introduces two critical intermediate-length baselines to SMT (USA) and IRAM 30−m (Spain), providing sensitivity to emission structures at spatial scales of ∼250 μas and ∼2500 μas (∼ 0.02 pc and ∼ 0.02 pc). Without these new baselines, previous EHT observations of the source in 2017 and 2018 lacked the capability to constrain emission on large scales, where a “missing flux” of order ∼1 Jy is expected to reside. To probe these scales, we analyzed closure phases–robust against station-based gain calibration errors–and model the jet base emission using a simple Gaussian component offset from the compact ring emission at spatial separations > 100 μas. Our analysis revealed a Gaussian feature centered at (ΔRA ≈ 320 μas, ΔDec. ≈ 60 μ as), projected separation of ≈ 5500 AU, with an estimated flux density of only ∼60 mJy, implying that most of the missing flux identified in previous EHT studies had to originate from different, larger scales. Brighter emission at the relevant spatial scales is firmly ruled out, and the data do not favor more complex models. This component aligns with the inferred position of the large-scale jet and is therefore physically consistent with the emission of the jet base. While our findings point to detectable jet base emission at 230 GHz, the limited coverage provided by only two intermediate baselines limits our ability to robustly reconstruct its morphology. Consequently, we treated the recovered Gaussian as an upper limit on the jet base flux density. Future EHT observations with expanded intermediate baseline coverage will be essential to constrain the structure and nature of this component with higher precision
Formation pathways and detectability of interstellar C
No full textAims. We explored N-bearing molecules of the general formula C2HNO. We provide their spectroscopic constants, structural properties relevant for detection, and reaction pathways to constrain their formation in the interstellar medium.
Methods. We investigated the molecular structures, spectroscopic constants, and the formation pathways for the isomers, and we report them here from ab initio calculations.
Results. Their formation pathways are mainly dominated by the components HCN + CO and HNC + CO → HNCCO for the second and third species, respectively. We identified five distinct families among the 15 isomers we investigated for C2HNO, in which global stability favors HCOCN (f1), while HNCCO (f6) has a smaller singlet–triplet gap than all the isomers. We also found additional formation pathways for HNCCO (f6) that have not been proposed before. Furthermore, we identified a connection between HCOCN (f1), HCONC (f2), HCNCO (f5), and HNCCO (f6) via proton transfer isomerization. HNCCO (f6) has also been proposed as a precursor to ethanolamine (NH2CH2CH2OH).
Conclusions. This suggests that HNCCO and other isomers we investigated might contribute to the formation of interstellar complex organic molecules and their observed abundances. In particular, we propose that HCONC (f2), c-HCNCO (f4), and HNCCO (f6 conformer) might be observable based on their dipole moments of 2.49, 3.58, and 1.25 Debye, respectively, which are comparable to the dipole moment of the already detected and most stable isomer HCOCN (2.50 Debye)
Isolation and Identification of
No full textPurebred chicken eggs are a source of proteins that provides complete nutrition for humans. The nutrient content in eggs is also a good growth medium for bacteria. Damage to eggs caused by bacteria can occur both inside and outside the hen's body. The main pathogenic bacteria contaminating eggs and processed egg products are Salmonella spp. The purpose of this study was to isolate and identify Salmonella sp. in purebred chicken eggs sold in the traditional Manokwari market. The research method was descriptive. Additionally, a purposive sampling method was used for the sampling procedure. Isolation of Salmonella sp. consisted of three stages: pre-enrichment, enrichment, and isolation of bacteria on the selective medium, Salmonella-Shigella Agar (SSA). Based on the results of Gram staining, cell morphology observations, and biochemical characterization, four samples of purebred chicken eggs (A2, A4, B5, and B7) containing Salmonella sp. The presence of Salmonella sp. in the egg samples tested was caused by the hygiene conditions, temperature, and egg shelf life in the storage area, as well as the hygiene of the eggshells
The Diversity of Molluscs (Gastropod and Bivalve) In Mangrove Rehabilitation and Natural Area Biak Numfor Regency In Indonesia
No full textThis study aimed to describe the diversity of mollusk species in rehabilitated and natural mangroves. The research variables included of mollusk species and individuals (gastopods and bivalves). The method used was descriptive, with observational techniques. There were 39 species of mollusks and 16 families with 2,922 individuals. There were 39 species of mollusks and 16 families with 2,922 individuals. These included 34 species of snail groups (Gastropod) and 5 species of shellfish groups (Bivalve). In addition, the percentage distribution of mollukc species was 18% (8 species out of 39 species) with diversity index (H) 1,09, dominancy (C) 0,12, and evenness (E) 0,84 (natural), then (H) 1,22, dominancy (C) 0,08, and evenness (E) 1,85 (rehabilitation). In addition, species diversity index values in the two mangrove forests were 2.52 (Ruar Village) and 2.70 (Yenusi Village) in the "moderate" category. A total of 72% of mollusk individuals were found in mangrove forests of Yenusi village, and the remaining 28% were present in Ruar village. This showed good adaptation, considering that the presence of mollusk species and individuals in the mangrove rehabilitation area was higher compared to their natural habitat. This showed that rehabilitation greatly influenced species composition at rehabilitation locations compared with natural locations
Comparative evaluation of methanol and water extracts: Antioxidant activity and total phenolic content of ten papuan medicinal plants
No full textThe use of Papuan medicinal plants as traditional medicine is widespread, but comprehensive and systematic research on their antioxidant activity and phenolic content remains limited. This study aimed to compare the antioxidant activity and total phenolic content (TPC) of 10 medicinal plant species traditionally used in Manokwari, Indonesia. Antioxidant activity was determined using the Ferric Thiocyanate (FTC) method, whereas TPC was quantified using the Folin-Ciocalteu assay in both aqueous and methanolic extracts. Multivariate analysis for the plants' phenolic content or antioxidant activity clustering was performed using principal component analysis (PCA). The methanolic extract of Myrmecodia jack exhibited the highest antioxidant activity (97.30%), while the aqueous extract of Persea americana showed a comparable potency (96.29%). The highest TPC was recorded in Areca catechu L. Statistical analysis revealed that the phenolic content accounted for 83.2% of the antioxidant activity in methanolic extracts and 59.6% in aqueous extracts. The TPC was markedly higher in the methanolic extracts. PCA classified samples into three distinct clusters: high phenolic, high antioxidant, and mixed profiles. These findings highlight the critical role of solvent polarity in bioactive compound recovery and the promising antioxidant potential of Papuan medicinal plants for natural product development
Two faces of L-type asteroids
No full textContext. L-types are a rare class of asteroids whose spectra indicate similarities with CO and CV chondrites, suggesting high abundances of refractory inclusions, particularly with respect to the calcium-aluminium-rich inclusion. This implies that their parent bodies were among the earliest chondrites to form.
Aims. We aim to identify L-types within selected asteroid families and to provide the first UV-VisNIR spectral characterisation of asteroids in this class. We further assess the spectral variability among L-types and evaluate the suitability of ESA Gaia UV-visible spectra for their identification.
Methods. We obtained VLT/X-shooter spectra of nine asteroids associated with L-type families. We classified them taxonomically using their UV-VisNIR spectra combined with the visual albedo and compared them to Gaia spectra and to ordinary, CO, and CV chondrites.
Results. Among the nine asteroids, we identified four L- and two M-types (Mahlke taxonomy), exhibiting diverse spectral features. Placing them into context of other L-types and known Barbarians using literature data, we find that L-types cluster into two groups based on spectra and albedo. One group depicts a deep 2 μm absorption and is denoted LL, while a second group shows a shallow or absent 2 μm feature and is denoted LM. We find a similar bimodality among CO and CV chondrites. Their steep UV-visible slopes and 1 μm features enable us to distinguish L- from S-types in Gaia’s spectral range.
Conclusions. The expanding census of L-types reveals a dispersed, possibly bimodal spectral distribution across multiple families, indicative of heterogeneity of the CO and oxidised CV chondrites parent bodies. Both the Aquitania and Brangäne family appear to come from such heterogeneous planetesimals. The Watsonia family is uniform and best represented by reduced CV chondrites. On the other hand, L-types with profound 2 μm absorptions such as (234) Barbara appear to be unsampled in the meteorite collection. Upcoming Gaia DR4 spectra and the ongoing SPHEREx mission will offer deeper insights into the distribution and mineralogical properties of this enigmatic class
Solar cycle evolution of ICME sheath regions at 1 AU
No full textAims. We investigate the evolution of interplanetary coronal mass ejection (ICME) sheath regions at 1 AU across solar cycles 23, 24, and the rising phase of 25, focusing on their variability and turbulence in relation to upstream solar wind conditions and the global heliospheric state.
Methods. Using a dataset of over 900 ICME sheath events, we applied statistical metrics such as the interquartile range (IQR) and the turbulence index (TI) to quantify variability and turbulence. The analysis compares full and rising phases of solar cycles and examines both local ICME parameters (e.g., sheath total pressure, non-radial flows) and global interplanetary indicators such as open solar flux (OSF).
Results. From solar cycle 23 to solar cycle 24, the sheath total pressure and magnetic field strength decreased by over 40% and 25%, respectively, accompanied by reduced turbulence and variability. In contrast, the rising phase of solar cycle 25 shows increased magnetic complexity, particularly in non-radial field components, despite stable bulk parameters. Non-radial flow patterns also shift from tangentially dominated in solar cycle 23 and solar cycle 24 to normal-dominated in solar cycle 25, suggesting changes in ICME orientation and sheath formation mechanisms. No significant correlation is found between OSF and sheath properties, indicating that local solar wind and ICME-specific factors are the primary drivers of sheath evolution.
Conclusions. The study reinforces the importance of upstream solar wind dynamics in relation to variations in plasma and magnetic field measured components of ICME sheaths. The derived trends in turbulence, magnetic orientation, and flow geometry suggest that sheath regions are sensitive indicators of solar cycle phase and should be considered as distinct, structured components in ICME modeling