Search Results (806)

In this study, three new terphenyl-substituted NPN ligands bearing pyridyl groups, two phosphonites and one diaminophosphine, were synthesized and fully characterized. Their coordination chemistry with copper(I) was investigated using CuBr and [Cu(NCMe)₄]PF₆ as metal precursors, affording six mononuclear Cu(I) complexes, which were characterized using NMR spectroscopy and, in selected cases, single-crystal X-ray diffraction (SCXRD) analysis. The NPN ligands adopt a κ³-coordination mode, stabilizing the copper centers in distorted tetrahedral geometries. The catalytic performance of these complexes in the S-arylation of thiols with aryl iodides was evaluated. Under optimized conditions, complexes 2a and 2b exhibited excellent activity and broad substrate scope, tolerating both electron-donating and electron-withdrawing groups, as well as sterically hindered and heteroaryl substrates. The methodology also proved effective for aliphatic thiols and demonstrated high chemoselectivity in the presence of potentially reactive functional groups. In contrast, aryl bromides and chlorides were poorly reactive under the same conditions. These findings highlight the potential of well-defined Cu(I)–NPN complexes as efficient and versatile precatalysts for C–S bond formation. Full article

Self-forgiveness is identified as a contributor to psychological wellbeing and may serve as a mechanism through which religiosity supports mental health. There is a dearth of research on wellbeing and the role of self-forgiveness in the English-speaking Caribbean. This preliminary study explored the relationship between religiosity, self-forgiveness, and wellbeing among persons with serious mental illness (SMI), a population largely overlooked in this context. A convenience sample of 362 out-patients receiving care in Trinidad and Tobago completed self-reported measures of self-forgiveness, the Religious Commitment Inventory, and Havard’s Flourishing Measure. Inferential statistics examined group differences in religiosity and wellbeing, and predictive relationships among key variables. Among persons with SMI, higher religiosity was significantly associated with greater wellbeing (p < 0.0001). Additionally, there was greater wellbeing among those who reported a propensity to self-forgive compared to those who did not (p < 0.0001). Self-forgiveness explained a significant part of the relationship between religiosity and wellbeing. Furthermore, among the non-highly religious, self-forgiveness was also significantly associated with greater wellbeing (p < 0.001). Our findings suggest that self-forgiveness may mediate the link between religiosity and wellbeing, highlighting its potential as a therapeutic coping mechanism for individuals with serious mental illness. This study adds to the growing literature on religious coping in mental health and underscores the need for further research to clarify the mediating role of self-forgiveness. Full article

Federated learning (FL) struggles under non-IID client data when local models drift toward conflicting optima, impairing global convergence and performance. We introduce entropy-regularized federated optimization (ERFO), a lightweight client-side modification that augments each local objective with a Shannon entropy penalty on the per-parameter update distribution. ERFO requires no additional communication, adds a single-scalar hyperparameter $\lambda$, and integrates seamlessly into any FedAvg-style training loop. We derive a closed-form gradient for the entropy regularizer and provide convergence guarantees: under $\mu$-strong convexity and L-smoothness, ERFO achieves the same $O(1/T)$ (or linear) rates as FedAvg (with only $O\left(\lambda \right)$ bias for fixed $\lambda$ and exact convergence when ${\lambda }_t\to 0$); in the non-convex case, we prove stationary-point convergence at $O(1/T)$. Empirically, on five-client non-IID splits of the UNSW-NB15 intrusion-detection dataset, ERFO yields a +1.6 pp gain in accuracy and +0.008 in macro-F1 over FedAvg with markedly smoother dynamics. On a three-of-five split of PneumoniaMNIST, a fixed $\lambda$ matches or exceeds FedAvg, FedProx, and SCAFFOLD—achieving 90.3% accuracy and 0.878 macro-F1—while preserving rapid, stable learning. ERFO’s gradient-only design is model-agnostic, making it broadly applicable across tasks. Full article

Background: We previously reported an interim safety and immunogenicity analysis of a Phase 3 trial in the Philippines of the EuCorVac-19 (ECV-19) COVID-19 vaccine with the COVISHIELD^TM (CS) comparator (ClinicalTrials.gov identifier NCT05572879). Here, we present full-year humoral immunogenicity analysis. Methods: Healthy adults over 18 years of age received two injections of ECV-19 or CS vaccines, with 4 weeks between prime and boost. Analysis was carried out in individuals with immunogenicity measurements available at all 4 timepoints (weeks 0, 6, 30, and 56; n = 535 for ECV-19 and n = 260 for CS). Results: 2 weeks after boosting (week 6), ECV-19 elicited higher median anti-RBD IgG (1512 vs. 340 BAU/mL, p < 0.001) and neutralizing antibodies (1280 vs. 453 median microneutralization (MN) titer, p < 0.001) compared to CS. Anti-RBD IgG remained higher for ECV-19 compared to CS through week 30 (412 vs. 238 BAU/mL, p < 0.001) and 56 (425 vs. 260 BAU/mL, p < 0.001). MN titers remained higher for ECV-19 compared to CS through week 30 (640 vs. 453, p < 0.001) and 56 (453 vs. 320, p < 0.001). Correlation between anti-RBD IgG and neutralization titers persisted throughout the study. Women generally exhibited greater antibody responses than men. In the first six months following immunization, the ECV-19 group had a median antibody half-life of 80 days for anti-RBD IgG and 112 days for MN titer. In the subsequent six months, antibody half-life increased to 237 days for anti-RBD IgG and 168 days for MN titer. Conclusions: Following initial prime-boost vaccination, ECV-19 maintained higher anti-RBD IgG and neutralizing antibody titers relative to the CS comparator over a full-year period. Full article

In this work, we report a green synthesis of zinc oxide (ZnO) nanoparticles using aqueous and ethanolic extracts of Tradescantia spathacea (purple maguey) as bioreducing and stabilizing agents, which are plant extracts not previously employed for metal oxide nanoparticle synthesis. This method provides an efficient, eco-friendly, and reproducible route to obtain ZnO nanoparticles, while minimizing environmental impact compared to conventional chemical approaches. The extracts were prepared following a standardized protocol, and their phytochemical profiles, including total phenolics, flavonoids, and antioxidant capacity, were quantified via UV-Vis spectroscopy to confirm their reducing potential. ZnO nanoparticles were synthesized using zinc acetate dihydrate as a precursor, with variations in pH and precursor concentration in both aqueous and ethanolic media. UV-Vis spectroscopy confirmed nanoparticle formation, while X-ray diffraction (XRD) revealed a hexagonal wurtzite structure with preferential (101) orientation and lattice parameters a = b = 3.244 Å, c = 5.197 Å. Scanning electron microscopy (SEM) showed agglomerated morphologies, and Fourier transform infrared spectroscopy (FTIR) confirmed the presence of phytochemicals such as quercetin, kaempferol, saponins, and terpenes, along with Zn–O bonding, indicating surface functionalization. Zeta potential measurements showed improved dispersion under alkaline conditions, particularly with ethanolic extracts. This study presents a sustainable synthesis strategy with tunable parameters, highlighting the critical influence of precursor concentration and solvent environment on ZnO nanoparticle formation. Notably, aqueous extracts promote ZnO synthesis at low precursor concentrations, while alkaline conditions are essential when using ethanolic extracts. Compared to other green synthesis methods, this strategy offers control and reproducibility and employs a non-toxic, underexplored plant source rich in phytochemicals, potentially enhancing the crystallinity, surface functionality, and application potential of the resulting ZnO nanoparticles. These materials show promise for applications in photocatalysis, in antimicrobial coatings, in UV-blocking formulations, and as functional additives in optoelectronic and environmental remediation technologies. Full article

The polyvalent nature of water is one often explored in fiction by Caribbean writers, and this paper will consider the ways that the representations of mermaids act as an extension of this exploration. Mermaids are central to a number of folk traditions across the Caribbean region and its diaspora. On islands, including Trinidad, Martinique, Carriacou, and Haiti, with names such as Fairymaid, Mama Glo, and La Siren, mermaids are often regarded as mothers and protectresses of both the sea and the creatures within it. This paper will analyse the representation of the mermaid in Monique Roffey’s The Mermaid of Black Conch (2020) and consider how the novel utilises the mermaid and an aquatic poetics to explore Kamau Brathwaite’s conceptualisation of a submarine unity for the Caribbean. Full article

This study evaluates the human health risks associated with exposure to arsenic in groundwater from a semi-arid region of Mexico, focusing on concentration levels and their temporal variation. Arsenic concentrations were analyzed using ordinary kriging for spatial interpolation, along with descriptive and inferential statistical methods. Human health risk was assessed through the following two key indicators: the Hazard Quotient (HQ), which estimates non-carcinogenic risk by comparing exposure levels to reference doses and carcinogenic risk (CR), which represents the estimated lifetime probability of developing cancer due to arsenic exposure. The mean arsenic concentration across both study years was 0.0200 mg/L, with median values of 0.0151 mg/L in 2015 and 0.0200 mg/L in 2020. The average HQ was 2.13 in 2015 and 2.17 in 2020, both exceeding the safety threshold of one. Mean CR values were 0.00096 and 0.00097 for 2015 and 2020, respectively, with a consistent median of 0.00072 across both years. A t-test was applied to compare the distributions between years. Both HQ and CR values significantly exceeded the recommended safety limits (p < 0.05), indicating that groundwater in the study area poses a potential carcinogenic and non-carcinogenic health risk. These findings underscore the urgent need for water quality monitoring and the implementation of mitigation measures to safeguard public health in the region. Full article

Clustering algorithms help handle unlabeled datasets. In large datasets, density-based clustering algorithms effectively capture the intricate structures and varied distributions that these datasets often exhibit. However, while these algorithms can adapt to large datasets by building clusters with arbitrary shapes by identifying low-density regions, they usually struggle to identify density variations. This paper proposes a Variable DEnsity Clustering Algorithm for Large datasets (VDECAL) to address this limitation. VDECAL introduces a large-dataset partitioning strategy that allows working with manageable subsets and prevents workload imbalance. Within each partition, relevant objects subsets characterized by attributes such as density, position, and overlap ratio are computed to identify both low-density regions and density variations, thereby facilitating the building of the clusters. Extensive experiments on diverse datasets show that VDECAL effectively detects density variations, improving clustering quality and runtime performance compared to state-of-the-art DBSCAN-based algorithms developed for clustering large datasets. Full article

Using graphs as a data structure is a simple way to represent relationships between objects. Consequently, it has raised the need for algorithms to process, analyze, and extract meaningful information from graphs. Therefore, frequent subgraph mining (FSM) algorithms have been reported in the literature to discover interesting, unexpected, and useful patterns in graph databases. Frequent subgraph mining involves discovering subgraphs that appear no less than a user-specified threshold; this can be performed exactly or approximately. Although several algorithms for mining frequent approximate subgraphs exist, mining this type of subgraph in graph collections has scarcely been addressed. Thus, we propose AGCM-SLV, an algorithm for mining frequent approximate subgraphs within a graph collection that allows structural and label variations. Unlike other FSM approaches, our proposed algorithm tracks subgraph occurrences and their structural dissimilarities, allowing user-defined partial similarities between node and edge labels, and captures frequent approximate subgraphs (patterns) that would otherwise be overlooked. Experiments on real-world datasets demonstrate that our algorithm identifies more patterns than the most similar state-of-the-art algorithm with a shorter runtime. We also present experiments in which we add white noise to the graph collection at different levels, revealing that over 99% of the patterns extracted without noise are preserved under noisy conditions, making the proposed algorithm noise-tolerant. Full article

This study presents the design and validation process of a new Bebras-based instrument to assess computational thinking (CT) in 7th-grade students. An initial version of the test, composed of 18 multiple-choice items, was piloted with 80 students and revised based on their performance and classroom feedback. The final version, composed of 17 tasks balanced across CT components and difficulty levels, was administered to 1513 students from 86 Spanish schools. No significant gender differences were found in overall performance, supporting the potential of Bebras tasks to provide equitable assessment. An exploratory factor analysis revealed a dominant factor explaining 20% of the variance, and additional evidence (Lord’s index = 10.61) supported the use of a one-dimensional model despite the ambiguous dimensionality of the domain. BBACT offers a balanced and theoretically grounded tool for assessing CT in compulsory education and lays the foundation for future work exploring its validity and application across diverse contexts. Full article

This paper demonstrates a method to perform movement analysis on rats named Movement Measurement in Hough Transform Space (MMHTS). The MMHTS method consists of representing locomotion of movement based on a system of linear equations and subsequently detecting the straight lines in the Hough transform space. Four straight lines $L_0$, $L_1$, $L_2$ and $L_3$ are detected, and with their information the angles between the beelines ${\alpha }_0$, ${\alpha }_1$, ${\alpha }_3$, intersection points $p_1\left(x_1,y_1\right)$, $p_2\left(x_2,y_2\right)$, $p_3\left(x_3,y_3\right)$ and their lengths $d_{L_0}$, $d_{L_1}$, $d_{L_3}$, $d_{L_4}$ are measured, corresponding to the locomotion geometry of the rats’ limps. Experimentally, the MMHTS method was employed for locomotion movement and the obtained results were compared with professional design software, detecting the following miscalculations: 0.144° for the angle measurements, 0.131 for the length measurement and 0.139 for the point detection. Based in the measurements results and the calculated errors, the MMHTS method is efficient and exhibits a high application potential in motion analysis. Full article

Background/Objectives: Natural oils are widely promoted and used around the world as part of skincare. Among them, extra virgin olive oil (EVOO) stands out for its broad range of organic compositions and well-known moisturizing properties. This study aimed to evaluate the effects of topically applied EVOO compared to petrolatum on skin barrier function (SBF) and microtopography. Methods: A within-person randomized clinical trial was conducted in healthy adult volunteers. EVOO and petrolatum were applied to defined areas on the volar forearm. Parameters related to the SBF, including stratum corneum hydration (SCH), transepidermal water loss (TEWL), temperature, and erythema, were assessed. The skin microtopography was evaluated through two approaches: (1) topographic parameters—surface roughness, desquamation, smoothness, and wrinkles; and (2) stratum corneum (SC) composition—corneocytes subtypes and the desquamation index (DI). The participants completed a tolerability questionnaire for each product. Results: A total of 54 participants (50% female; mean age: 28.57 ± 11.02 years) completed the study. Both EVOO and petrolatum significantly improved the SBF by increasing SCH and reducing erythema and skin temperature. Petrolatum additionally reduced TEWL. Regarding the skin microtopography, both products decreased the desquamation index and reduced the prevalence of mature corneocyte types (types 2–5). These effects were more pronounced with petrolatum. Notably, EVOO significantly increased the proportion of early-stage corneocytes (type 1). Conclusions: Both EVOO and petrolatum effectively enhanced the SBF and improved the microtopographic features of the skin. While petrolatum exerted a stronger occlusive effect by reducing TEWL and desquamation, EVOO uniquely promoted epidermal renewal by increasing epidermal turnover. Full article

This research evaluated the recovery and reuse of dolomitic calcareous amendment saturated with nutrients adsorbed from hydroponic effluent as a soil improver and its impact on the agronomic performance of Phaseolus vulgaris. Initially, the dolomitic calcareous amendment (DCA) was saturated with nutrients from the hydroponic effluent through adsorption tests. The characterization of the DCA was conducted before and after nutrient saturation to verify its composition. Soil analysis was carried out prior to the trial, and a completely randomized experimental design was applied with four treatments and five replications, totaling 20 experimental units for each soil type (sandy and clayey): T1 (control), T2 (raw dolomitic calcareous amendment—DCA), T3 (saturated dolomitic calcareous amendment—DCAS), and T4 (granulated dolomitic calcareous amendment—DCAG). Agronomic performance parameters of Phaseolus vulgaris were assessed to determine nutrient availability to the plant: number of pods, pod length (cm), number of seeds per pod, and weight of 100 seeds (g). Data normality was verified using the Shapiro–Wilk test, and results were analyzed using ANOVA and mean comparisons through Tukey’s test (p < 0.05) using InfoStat software 2020I. Additionally, plant tissue was analyzed to determine nutrient absorption in the seeds, and both soil types were analyzed after harvest. Adsorption results indicated that the DCA retained phosphorus, manganese, calcium, and zinc. According to the characterization, DCA primarily consisted of calcium and magnesium carbonates; following the saturation process, an increase in carbonate groups was observed due to calcium adsorption from the hydroponic effluent. Results in both soil types showed no significant differences in pod number, pod length, or seeds per pod, except for the weight of 100 seeds in sandy soil, where T1, T2, and T3 differed significantly from T4. Based on references, the phosphorus content in the harvested seeds from T3 in sandy soil is classified as sufficient. The findings demonstrate the potential of recovering and reusing nutrients from hydroponic effluent using DCA and transforming it into a value-added agricultural input for soil improvement, presenting a promising alternative for more sustainable and efficient agriculture. Full article

This article describes the case of the personal items found in common graves dated between 1939 and 1956 after the Spanish Civil War (1936–1939), located in Paterna’s cemetery (Spain). It was important in this study to know the state of the conservation of the objects and to obtain clues about their origin and use just as in a forensic study. This would allow the moral restitution of the historical memory of the victims of the war conflict. The multi-technique strategy has included light and electron microscopy, infrared spectroscopy and X-ray diffraction. Materials of the early 20th century used in pencil sharpeners, glasses, cutlery, lighters, rings, and buttons or medications contained in small bottles and boxes have been identified and have enabled the lives of their owners to be reconstructed during their imprisonment and execution. All these objects exhibited a thin layer of adipocere, a well-known compound in forensic science formed during the decomposition of human and animal corpses. Interestingly, rare corrosion processes have been identified in two of the objects analyzed, which are linked to their proximity to the decomposing corpses of the deceased. Copper sulfides and/or sulfates have been identified in the lighter, and scholzite, a zinc and calcium phosphate, has been identified in the glasses. Full article

Potatoes are highly sensitive to drought, particularly during tuber initiation. This study aimed to evaluate the effectiveness of film-forming (Vapor Gard [VG]) and metabolic (abscisic acid [ABA]) antitranspirants in mitigating drought stress and reducing tuber physiological disorders in four potato varieties. Two experiments examined the effects of VG and ABA antitranspirants on drought-stressed potato plants of four varieties (Challenger, Markies, Nectar, and Russet Burbank) grown in pots in a polytunnel (semi-controlled environment). Experiment 1 imposed severe drought by withholding irrigation until 70% of the available water content was depleted (reaching 15–17% volumetric water content within ~15 days), while Experiment 2 featured gradual drought stress from tuber initiation, with the soil volumetric water content declining to <10% over 30 days. Antitranspirants were applied at the start of the tuber initiation and two weeks later to assess their impact on the soil volumetric water content, stomatal conductance, relative water content, yield, and tuber physiological disorders. Drought significantly reduced the soil and plant water status, tuber yield, and quality across both experiments, with more severe effects observed in Experiment 1. VG and ABA had repeatable effects in both experiments and in all varieties, reducing water stress by preventing a large reduction in the relative water content during the tuber initiation and bulking stages. Both antitranspirants improved the tuber appearance by reducing the tuber skin disorder of russeting in the susceptible Challenger variety in both experiments, with VG being more effective than ABA. Beneficial reductions in the effects of drought from antitranspirants were also recorded in the volumetric water content, stomatal conductance, yield, and jelly end rot but not consistently in all varieties and in both experiments. The results show that antitranspirants have the potential to minimise water stress in droughted potatoes and subsequently reduce the physiological disorder of russeting and improve the tuber appearance of the Challenger variety. Full article