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Hot subdwarf stars from the Hamburg Quasar Survey
No full textHot subluminous stars (subdwarf B&O; sdB, sdO) are evolved low mass stars originating from red giants that lost their envelope almost entirely. The multitude of observed phenomena imply that several pathways may form hot subdwarfs, most involving close binary channels. The Hamburg Quasar Survey (HQS) has led to the discovery of many faint blue stars, including hot subdwarf stars. Many of the HQS-sdB stars have been studied in detail, but analyses of the helium-rich sdOB and sdO stars are lacking. The recent development of model spectra calulated from model atmopheres in local thermodynamic equilibrium (LTE) allowing for non-LTE departures (hybrid LTE/NLTE model spectra, the 2 nd generation Bamberg model grids ) enables us to improve the spectroscopic analyses of sdB stars as well as of the previously unstudied sdO stars allowing precise atmospheric parameters to be derived, while consistently accounting for parameter correlations and systematic uncertainties. The mission provided astrometric data of unprecedented quality, which allow fundamental stellar parameters to be derived from atmospheric parameters via parallax measurements. We used spectral energy distributions to identify composite-colour sdB binaries and present the result of detailed spectroscopic analyses of Gaia 122 non-composite subdwarfs from the HQS to identify potential evolutionary pathways. Comparison to evolutionary tracks both in the Kiel ( and the physical Hertzsprung-Russell ( diagram finds the location of the sdB stars on the extreme horizontal branch (EHB). Their derived mass distribution and median mass of 0.45,M_⊙ are consistent with the canonical EHB mass. We revisited the sample of known pulsating HQS-sdB stars and find no significant differences between their mass distributions and those of sdB stars that do not pulsate. The helium-rich sdOB and sdO stars are found near the helium main sequence (He-MS). The derived mass distribution of the extremely He-rich subdwarfs is broader (0.48 to 1.05,M_⊙) and peaks at a median of 0.70,M_⊙, significantly larger than those of the hydrogen-rich stars. Intermediate He-rich subdwarfs are also He-MS stars, but of lower mass (0.55,M_⊙) than the extremely He-rich subdwarfs. This strongly supports the merger scenario for the origin of He-rich sdO stars, in which two helium white dwarfs merge following orbital decay driven by gravitational-wave emission, producing a He-rich sdO or sdOB star. Comparing results from similar studies, we speculate that older populations produce more massive helium white dwarfs mergers
Screening and Identification of Gaba-Producing Bacteria from Lemea, A Traditional Fermented Food
No full textIntroduction: Gamma-aminobutyric acid (GABA) is a functional bioactive compound known for its health-promoting properties and is commonly found in fermented foods. Although numerous studies have investigated GABA production from various fermentation substrates, Lemea, a traditional fermented food from Indonesia, remains an underexplored source of GABA-producing bacteria. Objective: This study aimed to quantify GABA production by bacterial isolates obtained from Lemea and to identify the most potent GABA-producing strain through molecular characterization. Methods: Six bacterial isolates previously screened for GABA production were rejuvenated and cultured in de Man, Rogosa, and Sharpe Broth (MRSB) supplemented with glutamic acid for 36 hours. GABA concentrations in the culture supernatants were quantified using an ultra-performance liquid chromatography-photodiode array (UPLC-PDA) method (18-5-167/MU/SMM-SIG), with analyses performed in duplicate. The isolate exhibiting the highest GABA production was identified by 16S rRNA gene sequencing.Results: The results showed that GABA production among the isolates ranged from 40.09 ± 1.17 mg/L to 113.03 ± 0.15 mg/L. The highest GABA-producing isolate was molecularly identified as Staphylococcus epidermidis, exhibiting a 100% sequence similarity coefficient. Conclusion: These findings demonstrate that Lemea is a promising source of GABA-producing bacteria. The identification of Staphylococcus epidermidis as a high GABA-producing strain suggests its potential application in the development of functional fermented food products
The use of starter cultures in lab-scale cacao fermentation and its impact on non-volatile compounds and flavor profile
No full textIndonesian cacao exhibits strong potential as Fine Flavor Cacao (FFC), as demonstrated by its recognition at international events. However, maintaining consistent cacao bean quality remains a major challenge, largely due to spontaneous fermentation processes that result in variable microbial communities. This study aimed to optimize laboratory-scale cacao bean fermentation through the application of defined microbial starter cultures. Fermentation was conducted using either a single yeast starter (Pichia kudriavzevii) or a mixed starter culture comprising P. kudriavzevii, Lactiplantibacillus plantarum, and Acetobacter tropicalis. Each treatment utilized 1.2 kg of fresh cacao beans and was performed in duplicate. Following fermentation, the non-volatile compounds composition and flavor profile of the cacao beans were analyzed. The results showed that fermentation with the Pichia starter produced cacao beans characterized by more pronounced floral and woody notes, whereas the mixed starter culture resulted in cacao beans with enhanced fresh fruit notes. Both fermentation strategies yielded cacao beans with high-quality flavor profiles. These findings highlight the potential of starter culture-based fermentation as a viable approach for small-scale cacao processing to achieve consistent and tailored flavor characteristics
Multiplicative Scatter Correction Improves Near-Infrared Spectroscopy–Based PLS Models for Acetic Acid Quantification in Jamblang Vinegar
No full textJamblang (Syzygium cumini L.) vinegar is a potential functional fermented product that requires rapid and reliable quality assessment. This study developed a near-infrared spectroscopy (NIRS)-based method combined with partial least squares regression (PLSR) to quantify acetic acid content in jamblang vinegar. Vinegar samples representing a wide range of acetic acid concentrations were obtained through varied fermentation conditions and analyzed using a reference enzymatic method. NIR spectra were preprocessed using Multiplicative Scatter Correction (MSC) to reduce scattering effects caused by sample heterogeneity. PLSR models constructed from MSC-treated spectra showed improved predictive performance compared with uncorrected spectra, achieving a coefficient of determination (R2) of 0.995 and a residual predictive deviation greater than 2.3. Regression coefficient analysis identified wavelength regions associated with O–H and C–H overtone vibrations as key contributors to acetic acid prediction. The results demonstrate that NIRS coupled with MSC-enhanced PLSR provides a rapid, non-destructive, and accurate approach for acetic acid determination in jamblang vinegar, supporting its application for routine quality control and fermentation monitoring
Extraction and Isolation of Active Fraction from
No full textGanoderma boninense is a fungus that causes basal stem rot disease in oil palm plants. This fungus disrupts the transport of water and nutrients from the soil, leaf chlorosis, stem decay, fruitlessness, and ultimately death. This study is one of the first to specifically explore the bark of Senna multijuga as a source of antifungal compounds against Ganoderma boninense. Previous studies have focused more on leaf extracts from other Senna species, so the use of S. multijuga bark provides a new contribution to the search for biological agents to control G. boninense. This study aims to extract and isolate the active fraction from S. multijuga bark as antifungal agents against G. boninense. The study was conducted in three stages. The extraction and isolation of the active fraction from S. multijuga bark as antifungal agents against G. boninense, the determination of the chemical composition of the S. multijuga bark, and the antifungal activity of the active fraction against G. boninense in vitro. Based on the GC-MS results for fraction-1 from S. multijuga bark showed the main compounds of 1-hexadecene (5.51%), 1-octadecene (8.29%), hexadecanoid acid (10.46%), 2-ethoxycyclohexanol (5.53%), 9,12-octadecadienoic acid (8.91%), 9,12,15-octadecatrienoic acid (7.70%), 2-hexadecen-1-ol (5.48%), 1-docosene (3.33%), 2-pyridol (6.28%), and calotropenol acetate (6.52%). A concentration of fraction-1 at 1.50 ppm can inhibit the growth of G. boninense (0.32 cm/day), inhibition of G. boninense (67,46%), and produce thin white mycelium that collects in the middle of the medium
Quantum skyrmion qudit in a triangular-lattice magnet
No full textSince the pioneering work Lohani et. al.. Phys. Rev. X 9, 041063 (2019), it became clear that quantum skyrmions have highly unusual properties as compared to the classical skyrmions and, due to their quantumness, cannot be described by continuous magnetic textures akin to the classical skyrmions. Competing nearest-neighbor and next-nearest-neighbor ferromagnetic and antiferromagnetic interactions in triangular spin-frustrated magnets lead to the formation of quantum skyrmion states. In frustrated magnets, skyrmions are characterized by the helical degree of freedom, which can store quantum information. In the limit of a weak electric field, the system can be described as a two-level system, i.e., a skyrmion qubit. Here, we propose a more general formulation of the problem and obtain general analytic solution of the model previously introduced in Psaroudaki et. al. Phys. Rev. Lett. 127, 067201 (2021). Our solution is valid not only for small barrier but also for the arbitrary electric field. In the case of a significant barrier, we prove that the system’s state is not a Skyrmion qubit as it was thought before, but a Skyrmion qudit. We constructed the density matrix of the Skyrmion qudit and studied its evolution in time. The obtained results suggest that the proposed model can be exploited further to meet the needs of quantum information theory and quantum skyrmionics. We showed that the norm of coherence of the skyrmion qudit is a thousand times larger than the coherence of the skyrmion qubit. The obtained result opens new perspectives for quantum skyrmion-based resource theory
Negative-Refractive-Index Behavior in a Periodic Photonic Metamaterial: Unit-cell Topology Tailoring for Broadband Response
No full textThis paper examines how systematic control of unit-cell topology governs dispersion characteristics and bandwidth stability in configured periodic structures with numerical simulations. Distinct from the existing literature, the study targets a negative refractive index over a broad frequency range, while neural network–based optimization is used as a supporting tool to efficiently guide for bandwidth maximization. Comprehensive analysis is employed to optimize bandwidth effectively and validate the applicability of the resulting low-dispersion periodic structures. For the optimized unit cell, the third photonic band spans a wavelength range 1388–1631 nm (after model enhancement 1429–1578 nm) covering the S, C, and L optical communication bands, demonstrating broadband and stable dispersive behavior beyond a narrow resonance regime. The obtained results are thus expected to enhance the performance of negative-index based photonic components used in optical and photonic communication systems, compact antenna architectures, and advanced material engineering
Eye-safe non-line-of-sight localization using compact nanosecond laser diodes and single-photon-avalanche-diode arrays
No full textActive optical non-line-of-sight (NLOS) imaging faces severe photon loss and stringent timing demand, often motivating bulky, non-eye-safe systems with femto- or picosecond lasers and spatial scanning schemes. We present an eye-safe, compact NLOS localization approach that uses a single-photon-avalanche-diode array with on-chip timing and inexpensive and compact nanosecond pulsed laser diodes. To circumvent first-photon induced saturation in soft-gated detectors, the scene is illuminated from two positions placed outside the detector's field of view. The detector observes the relay wall in parallel, yielding a photon-efficient, non-confocal measurement. Transient simulation of multiple scattered laser pulses, that returned to the relay wall after an object interaction, are used with back projection reconstruction to assess illumination schemes. It is shown that superimposing reconstructions from two non-central illumination positions reduces the pulse-width-induced uncertainty of the determined target position, which is validated by measurements. Further compensation of the extended pulse width is analyzed with temporal and spatial filters. Matched filtering in the temporal domain outperforms spatial edge detection in the reconstruction volume, so that localization resolution becomes primarily limited by the detector's temporal resolution and measurement geometries rather than temporal pulse width. We outline a hybrid LiDAR-NLOS system for direct relay-wall calibration, pointing toward practical, eye-safe NLOS localization, with compact solid-state hardware
Implantation de la méthode pédagogique
No full textIntroduction : Les défis inhérents à l’enseignement dans le milieu des soins intensifs sont en lien avec l’environnement stressant, le grand débit de patients et la charge de travail. L’utilisation de la méthode pédagogique One Minute preceptor (OMP) a été identifiée pour répondre à cette problématique. Objectif : Identifier les barrières et les facilitateurs à l’utilisation de l’OMP dans une unité de soins intensifs pédiatriques (SIP) avant son implantation. Méthode : Il s’agit d’une étude descriptive qualitative. Les médecins du service et les résidents en stage aux SIP ont pris part à des entrevues individuelles semi-structurées où les barrières et facilitateurs à l’implantation de l’outil ont été explorés puis analysés par thème. Résultats : Les principaux facilitateurs identifiés sont : sa compatibilité avec l’organisation et la culture du service et la réponse à un besoin. Les principales barrières à l’implantation sont : la crainte de mettre les résidents mal à l’aise si la méthode est utilisée devant un grand groupe de personnes dans un contexte de culture de performance, le manque de temps accordé à l’enseignement, le risque d’augmentation de la charge mentale des médecins et la méconnaissance des étapes de la méthode. Conclusion : Cette étude indique que l’OMP est un outil prometteur dans le cadre de l’enseignement en milieu clinique aux SIP. Une réflexion à un niveau plus systémique concernant la culture de performance pourrait contribuer à créer un environnement sécuritaire et collaboratif qui puisse favoriser les apprentissages selon un modèle expérientiel
induced reactions for nuclear astrophysics at sub-barrier energies
No full textReactions induced by alpha particles, which play an important role in nuclear astrophysics, were investigated at energies below the Coulomb barrier using our IFIN-HH facilities. These include the 3 MV Tandetron™ accelerator [1], a local laboratory and the ultra-low background laboratory Bq [2] located in a salt mine. Thick Zn metal targets were irradiated at laboratory energies in the range = 5.4–8.0 MeV in 0.20 or 0.25 MeV steps. By measuring the prompt gamma-ray yields and the decay of radioisotopes produced in each reaction, in the Nuclear Astrophysics Group (NAG) and the Bq laboratories [3], we determined the thick target yields, which were subsequently used to evaluate the reaction cross sections. We succeeded in determining the cross section for +64Zn for the proton evaporation and radiative alpha capture channels at the lowest energies ever measured, deep inside the Gamow window for stellar processes at temperatures of 2–3 GK