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Stochastic time series modelling of TESS photometry of classical t tauri stars
(Elsevier, 2025) Koen, Chris
A standard approach to extracting information from classical T Tauri star (CTTS) light curves is to search for periodicities. This paper, by contrast, focuses on time domain fitting of standard linear stochastic time series models to such data. The necessary statistical time series analysis tools are covered in some detail. The theory is then applied to TESS 10-minute cadence photometry of 13 CTTSs. In most instances, completely satisfactory models could be fitted to the observations; in the remainder of cases models may still capture the gist of the variability. Models are quite parsimonious, requiring only one to six parameters. Statistical properties of the model residuals are also studied. The distributions of the residuals are generally highly non-Gaussian, with large positive kurtosis.
Identifying essential chemical descriptors for auxins, cytokinins, and gibberellins using principal component analysis
(Springer, 2025) Sershen Naidoo; Quintana‑Zaez Julio César; Gómez Daviel
Auxins, cytokinins, and gibberellins are plant growth regulators (PGRs) that significantly influence plant growth and development. Investigating their molecular descriptors is vital for understanding how these PGRs work in intricate networks, influencing each other’s activity and responding to environmental cues, but this can be challenging given that PGRs often mimic or interact with naturally occurring plant growth regulators, which are themselves a complex group of chemicals with diverse structures and functions. This motivated the present study, which evaluated the effectiveness of principal component analysis (PCA), a statistical method renowned for reducing the dimensionality of intricate datasets, in identifying the key molecular descriptors that distinguish these three plant growth regulators. A total of 212 molecular descriptors were previously determined. Using PCA, the study identified critical chemical descriptors for auxins, cytokinins, and gibberellins, including ring count, presence of secondary alcohols, and terminal primary C (sp2) structures. Importantly, the study also confirmed the value of PCA in identifying key molecular descriptors for PGRs in studies focused on understanding their mechanism(s) of action. This paper introduced a novel methodological approach that contributes meaningfully to the understanding of PGRs.
Characterization of zrc-v-ti-zrc multilayer hydrogen storage thin films prepared by e-beam evaporator
(Elsevier Ltd, 2025) Rampai, Mojesi Monica; Seroka, Ntalane Sello; Khotseng, Lindiwe Eudora
In this study, a physical deposition method was used to prepare a ZrC–V–Ti–ZrC multi-layered stack film that was deposited on Ti and borosilicate glass substrates. The hydrogenation was achieved by thermal annealing of samples at temperatures of 200, 300, 400, and 550 °C in a pure hydrogen environment with a flow rate of 100 sccm for 30 min. RBS revealed that the multilayers are thermally stable, showing no sign of intermixing of layers up to 600 °C. It revealed the presence of oxygen in all the layers with a significant amount. ERDA revealed that a significant amount of H was near the surface and dropped towards the bulk of the samples, which is the middle layers (V and Ti layers) location. The probing towards the inner last layer (buried ZrC layer) of the multilayer stack showed an increase in the H amount detected. H amount decreased as the oxygen amount was increased in the layers indicating the negative impact of oxygen in the system, such that the total H amount in the samples with the TiO (1:1) and VO (1:1) was 99.122 at.% at 200 °C while that of Ti2O3 (2:3) and V2O3 (2:3) was 60.016 at.% at 300 °C indicating a significant change. The optimum temperature for the highest H amount observed was found to be between 200 °C and 300 °C. The as-deposited sample only showed the surface H, which is normally due to the atmosphere's hydrocarbons. The Raman spectroscopy results indicated that there was a significant decrease in the intensity of the D and G peaks due to annealing in a hydrogen environment. This suggests that the extent of hydrogen absorption, which occurs predominantly in the temperature range of 200–300 °C, is inversely related to the intensity of the D and G peaks. There was more formation of the sp3 at temperatures between 200 °C and 400 °C in the samples as seen by the decrease in the sp2/sp3 ratio from 0.13 to 0.003. XRD revealed the presence of diffraction phases, i.e., ZrC (111), ZrC (400), V2O5 (001), Ti (100), Ti (101), and Ti (103) in addition to the TiH2 and the broadening of peaks for the system annealed at 200 °C and 300 °C due the high H amount, which is consistent with ERDA results. These results indicate the suitability of this system in hydrogen storage applications, provided it is optimized by eliminating oxygen contamination.
Dental genomics in Africa: colonial legacies and research gaps
(Frontiers Media, 2025) Kabbashi Salma; Chetty Manogari; Roomaney Imaan A.
Oral health disparities are closely linked to broader health inequalities, particularly in global health contexts where disproportionate emphasis is placed on diseases other than oral health. In the field of dental genetics, recent investigations have highlighted persistent challenges and barriers in African genomic research. Colonial legacies continue to influence the structuring of research agendas and contribute to the marginalization of indigenous knowledge systems. We discuss the implications of these historical dynamics for the relevance of genetic research findings, and addresses the emerging ethical considerations in clinical applications and community engagement. We emphasize the need for equitable and culturally inclusive approaches to expand our genetic understanding of dental pathologies in underrepresented African populations.
Public participation and service delivery: A case study of Langa community in Cape Town, South Africa
(University of the Western Cape, 2025) Mohmmed, Nahid Siddig Ahmed
This study examines the role of developmental local government in involving the community to improve service delivery in Langa township in Cape Town, South Africa. According to academic research review, there are contributions of public participation in service provision. South Africa has developed a legal framework to strengthen public participation and involve the residents in the decision-making process. However, despite the legal frameworks and Batho Pele principles yet, Langa is an urban informal settlement, historically disadvantaged and more than half of its population does not access their basic rights and lives in unlivable dwellings. Furthermore, there is a need for community consultation for better decision-making. Therefore, public participation has different forms such as institutionalised spaces and citizenry-designed participatory spaces. Hence, this study aimed to assess the extent to which the community has been involved in the decision-making process. The overall aim of this study was achieved by evaluating the level of service delivery and forms of participatory structure in the community of Langa, as well as identifying factors that affect community participation and their well-being in Langa.