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Modelling δ Scuti pulsations: a new grid of p, g, and f modes across pre-main-sequence to post-main-sequence evolution
No full textSpace-based photometry reveals regular high-frequency patterns in many young Scuti stars. These pulsations provide a powerful means of inferring stellar properties, particularly ages, for young Scuti stars for which traditional age-dating methods are poorly constrained. Realizing this potential requires theoretical models that capture the complexities of stellar structure and evolution. We present a comprehensive grid of 25 million stellar pulsation models, computed using the MESA stellar evolution code and the GYRE stellar oscillation code, tailored to Scuti stars. The grid spans a wide range of masses, metallicities, and rotation velocities, and covers evolutionary phases from the early pre-main-sequence through the main sequence (MS) and into the post-main-sequence contraction phase. For each model, we computed adiabatic pulsation frequencies for degrees ─3, capturing p modes, g modes, f modes, and their interactions through avoided crossings. We find that f and low-order g modes have mode inertias comparable to or lower than the fundamental radial mode during the late pre-MS and early MS, implying that these modes should be observable. We revisit Scuti scaling relations and map asteroseismic observables, including the large frequency separation () and phase offset parameter (), across age, mass, metallicity, and rotation. This new model grid, which is publicly available, improves upon previous such model grids by facilitating interpretation of Scuti pulsations, allowing for more reliable age estimates and tighter constraints on stellar evolutionary pathways, and planet formation in A- and F-type stars
American Institute of Aeronautics and Astronautic Scitech Forum 2026
No full textThis paper presents measured spectral irradiance from the OSIRIS-REx Sample Return Capsule reentry (24 September 2023) as measured from one window of the NASA NA522 airborne observation platform. Two instruments with a nominal 10 nm bandwidth and 0.083 nm resolution were successfully used at this window: (1) Instrument 780, targeting atomic oxygen 777 nm emission; and (2) Instrument 820, targeting atomic nitrogen and atomic oxygen emissions in the vicinity of 820 nm. Useful data was acquired for an 8 s period of the re-entry, including at peak radiative heating. The design and calibration of these instruments is presented, along with the image processing methodology used to extract spectral data from the raw images. As the re-entry occurred during daylight hours, the significant sky background was a key consideration in the instrument design. Time resolved spectral irradiance measurements are presented for four bandpasses; one for the oxygen 777 nm triplet, and three for atomic nitrogen lines near 820 nm. No significant atomic oxygen emissions were observed near 820 nm. A 300 ms time-averaged spectrum at predicted peak heating is presented for both instruments. The results presented in this paper are the basis for future analysis of the shock-heated gas emissions from the OSIRIS-REx capsule re-entry
Usability testing for an open educational resource to teach language and culture
No full textThis study focused on procedures for creating, testing, and developing a set of reusable online resources for use in English for academic purposes programmes. The aim of the materials was to help migrants and refugees develop the linguistic and cultural skills, knowledge, and understanding they would need to engage, interact, and collaborate effectively in a multicultural context. Development of the materials involved an iterative process using a three-stage approach:
1.
Expert review: Experts in relevant fields worked through the first version of the materials and provided critical feedback, which guided initial revisions.
2.
Usability testing groups: Small groups of target users (students and teachers) used the revised materials in workshop settings, and data were gathered from observations, interviews, and written comments.
3.
Wider evaluation: Larger-scale use and evaluation of the materials (which is ongoing, beyond the scope of this paper).
This article reports on the second stage
Development of neuromorphic event-based imaging spectroscopy for hypersonic flight observation
No full textEnhanced capability to collect vital hypersonic flight data is required to better understand the physics of the flow around spacecraft entering Earth’s atmosphere. Daytime recording, while possible, remains particularly challenging and often requires compromises due to saturation and noise in this environment. Using novel, bio-inspired event-based cameras allows spectral measurements to be performed equally well during both day and night, without modifications to instrumentation - overcoming a major current limitation associated with daytime tests. Combining these cameras with high-resolution spectroscopy enables more reliable collection of critical data, such as temperature and species composition in the flow around re-entering spacecraft. Measurements were performed using a novel neuromorphic spectroscopy system and a range of light sources. These tests were conducted in the 400–900 nm spectral region to match the operational range of the event-based camera. The acquired data show that both broadband and discrete line spectra were obtained. Results for dynamic range, daytime performance, and long-range spectroscopy demonstrate improved performance of the event-based system compared to the conventional cameras typically used under similar conditions. This work demonstrates, for the first time, that a spectroscopy system based on neuromorphic technology is capable of successfully recording emission spectra. These results represent a landmark step toward developing advanced spectroscopy diagnostics for hypersonic flight observation, including Earth re-entry missions
The biocompatibility of a novel polyether ether ketone (PEEK) stoma device with human epidermal keratinocytes
Full text linkSurgical stomas are essential interventions for many medical conditions, however, can create physical complications, such as peristomal skin irritation. Medical stoma devices (MSD) are a potential treatment to mitigate such complications. Polyether ether ketone (PEEK) is a promising material for implantable MSD due to its established biocompatibility within orthodontic and orthopaedic applications. However, its cytocompatibility with human epidermal keratinocytes has not been evaluated according to ISO 10993-5:2009 guidelines. This study aimed to assess the biocompatibility of a novel PEEK MSD with human keratinocytes (HaCaT cells). Cells were cultured on discs of PEEK, surface-modified PEEK (m-PEEK), and polylactic acid (PLA). Surface topography was investigated via SEM to assess surface roughness (Sa, Sz), and water contact angle (WCA). m-PEEK demonstrated increased Sa and WCA compared to PLA and unmodified PEEK. Cell proliferation and viability were evaluated using CyQUANT™ and AlamarBlue™ assays and no significant differences were observed among PLA, PEEK, and m-PEEK. Cell adhesion was assessed using an adhesion assay, with m-PEEK demonstrating significantly higher cell adhesion than PLA (p < 0.05), with cell attachment confirmed via SEM imaging. Cytokine analysis of supernatants using Luminex Immunoassay revealed two (IL-1α and IL-6) of six cytokines outlined in the ISO 10993-20:2006 guidelines were elevated in the presence of PEEK at 72 h. These findings suggest that PEEK is non-cytotoxic and biocompatible with human keratinocytes. Further studies are warranted to assess PEEK's compatibility with colonic cells, 3D skin models, and in vivo systems (including for chronic inflammatory responses) for MSD applications
Impact of low-cost carrier exit on tourism revenues
No full textA low-cost carrier withdrawal triggers the airline substitution effect as remaining full-service carriers raise fares, reducing tourism revenues. Meanwhile, a transport mode shift to ground transportation may boost local spending and generate additional regional tourism revenues. This study uses a unique difference-in-differences framework to assess the net impact of low-cost carrier withdrawal from New Zealand's regional markets. Findings reveal the “airline substitution effect” outweighs the “transport mode shift”, causing a net tourism revenue drop after a low-cost carrier exit. Policy implications suggest prioritising low-cost carrier retention through targeted subsidies and support to enhance regional tourism and economic growth
Exploiting Paraphaeosphaeria minitans and Its Antifungal Metabolites as Bio‐Fungicides for Eco‐Friendly Management of Head Rot Disease in Cabbage
No full textCabbage head rot, caused by Sclerotinia sclerotiorum, threatens crop yield and quality. Among the 21 mycoparasitic fungi isolated from sclerotia, dormant structure and primary sources of inoculum for the pathogen, the strongest antagonism (78.51% mycelial growth inhibition) was observed in Paraphaeosphaeria minitans strain TNAU-CM 1. Scanning electron microscopy (SEM) revealed its destructive colonisation, including pycnidia and pycnidiospore formation, with visible shrinkage and deformation of sclerotia. Gas chromatography–mass spectrometry (GC–MS) analysis identified 24 bioactive metabolites at the point of interactions between P. minitans TNAU-CM 1 and S. sclerotiorum TNAU-SS-5 strains in dual-culture assays. Further, crude metabolites from P. minitans TNAU-CM 1 cultures inhibited the pathogen's mycelial growth by 54.4% at 100 ppm. In the molecular docking of 14 key compounds, linoleic acid and butyl octyl phthalate, well-known antifungal compounds, displayed the highest binding affinity of −7.6 and −6.2 kcal/mol, respectively, against Saccharomyces cerevisiae cupin protein (1ZNP) YML079w, a homologue of SsYCP1, a YML079-like cupin protein (YCP) and a virulence molecule from S. sclerotiorum. Field trials demonstrated that foliar application of P. minitans TNAU-CM 1 stock solution (8–10 × 108 spores per mL) at 5 mL/L dilutions significantly reduced disease incidence and the crops produced a yield of 41.37 tons/ha, comparable to chemical fungicide treatment (43.51 tons/ha). Thus, molecular interaction studies and field evaluations suggest that P. minitans TNAU-CM 1 is a promising eco-friendly alternative to synthetic fungicides for the management of cabbage head rot. Furthermore, our findings indicate that linoleic acid and butyl octyl phthalate are the key antifungal metabolites of P. minitans, active against S. sclerotiorum and will serve as potential candidates for developing bio-fungicide formulations to control head rot in cabbage
Theoretical screening of P-block single atoms anchored on g-C3N4 for NO reduction to NH3
No full textThe NO reduction reaction (NORR) is considered an attractive strategy for efficient NO removal and sustainable ammonia (NH3) production. Herein, the catalytic behaviour of eleven p-block single atoms anchored on g-C3N4 monolayer (SAC@g-C3N4, SAC[double bond, length as m-dash]B, Al, Si, Ga, Ge, As, In, Sn, Sb, Te and Bi) is systematically investigated as NORR electrocatalysts using density functional theory (DFT) calculations. The thermodynamic stability of SAC@g-C3N4 and its suppression of hydrogen evolution were examined. In addition, the thermodynamically favourable reaction pathway was identified based on the Gibbs free energy change, where B@g-C3N4 catalyst exhibited a low limiting potential (UL) of −0.02 V. Furthermore, charge density analysis and projected density of states (PDOS) revealed the origin of NO activation. This work screens pure p-block SAC@g-C3N4 for the NORR and provides an atomic-level understanding of the reaction mechanism. These findings would aid the novel design of NORR catalysts and provide theoretical insights for the experimental synthesis of high-performance electrocatalysts
Crop disease surveillance through integration of machine and deep learning in the face of climate change
No full textEarly detection of potato plant diseases is vital for agricultural productivity, plants, economy, and human health. Preventing disease spread minimizes agricultural losses and safeguard food production. Potatoes are a major food source worldwide, and reduced production could contribute to food insecurity. Precise and automatic plant disease detection represents a fundamental research topic. This study focuses on detecting potato disease risk associated with Early Blight (EB) and Gray Mold (GM) spores under the influence of dynamic climate. The aim of this study is to utilize Deep Learning (DL) and Machine Learning (ML) technologies for the disease detection of infected and healthy potato plants in Atlantic Canada, for Prince Edward Island (PEI) and New Brunswick (NB); and United States (U.S.), for Maine, to mitigate agricultural losses. The novel potato dataset used in the study comprised 5630 instances, with 1482 instances from PEI, 3032 from NB, and 1116 from Maine. A hybrid Artificial Neural Network - Random Forest (ANN-RF) is implemented model for binary disease classification, where the presence of EB or GM spores is considered as a single ‘diseased’ class. The hybrid ANN-RF model yields testing accuracy of 91 % for PEI, 86.5 % for NB, 88.4 % for Atlantic Canada, 84 % for Maine, and 87.5 % for combined data, with training accuracy of 97 %, 94.7 %, 91 %, 94.5 %, and 91 %, respectively, and log loss values under 0.4. These results highlight the potential of the developed model for disease detection in potato crops based on historical spore and weather data. The research findings examine potato diseases across multiple regions, uncovering geographical dissimilarities that shape disease prevalence, patterns, and management effectiveness. The study emphasizes the effectiveness of the hybrid model for predicting the likelihood of potato disease based on pathogenic spores, demonstrating the importance of AI in enhancing agricultural productivity, pesticide inventory control, and promoting sustainable farming practices
Prevalence and determinants of HIV testing among adolescent girls and young women in 28 sub-Saharan African countries
No full textBackground: HIV and AIDS remain a major global public health issue with the largest burden in sub-Saharan African (SSA) countries. Adolescent girls and young women (AGYW) in the sub-Saharan African region experience intersecting vulnerabilities that may increase their exposure to HIV, while also constraining their engagement with treatment and care. HIV testing is crucial in the AIDS response for both prevention and treatment. Therefore, understanding HIV testing practices, especially among priority populations. We examined HIV testing and associated factors among AGYW (15–24 years) in 28 SSA countries.
Methods: We analysed Demographic and Health Survey datasets from 28 SSA countries from 2010 to 2022 focusing on data collected from AGYW aged 15–24 (n = 58,263) who had screened for HIV in the last survey conducted in each country. We merged all weighted datasets from 28 countries to generate the prevalence of HIV testing among AGYW in each country and to provide an overall prevalence in SSA. We then conducted bivariate and multivariable binary logistic regression analysis to examine factors associated with HIV testing and presented the results in crude odds ratio [cOR] and adjusted odds ratio [aOR] with corresponding confidence intervals (CIs).
Results: Our results showed that the overall prevalence of HIV testing among AGYW across the 28 SSA countries was 63%, with Zambia and Mali having the highest and lowest prevalence at 76% 6.70% respectively. Being in the age bracket 20–24 [aOR = 2.22, 95% CI = 2.08–2.37], comprehensive HIV knowledge [aOR = 3.76, 95% CI = 2.60–5.43], higher formal education [aOR = 2.23, 95% CI = 2.02–2.46], and three and above lifetime sexual partners [aOR = 1.41, 95% CI = 1.29–1.55] were all associated with HIV testing. Also, past year experience of STI [aOR = 1.25, 95% CI = 1.11–1.41], being employed [aOR = 1.08, 95% CI = 1.02–1.16], pregnancy history [aOR = 1.09, 95% CI = 1.03–1.14], high household wealth index [aOR = 2.26, 95% CI = 1.97–2.59] and being in a union [aOR = 3.23, 95% CI = 2.97–3.51] were associated with HIV testing.
Conclusion: Concerningly, 21 countries, representing 75% of the countries included in the current study, have HIV testing coverage below 50% for AGYW. Collaborative efforts are needed to fast-track HIV screening/testing for AGYW considering their disproportionate vulnerability to HIV exposure