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Analysis of parameter space, bifurcation and symbolic dynamics of evolutionary strategies on a one-dimensional regular lattice
No full textThe payoff matrix parameters, bifurcation, topological conjugacy and symbolic dynamics of the evolutionary game dynamical systems on a one-dimensional regular lattice are thoroughly investigated in this paper. Based on the properties of addition and scalar multiplication invariance, an effective dimensionality reduction method is proposed to classify the payoff matrix parameters, resulting in 27 evolutionary game dynamical systems. Furthermore, their qualitative dynamics is presented and 14 topological conjugacy classes are obtained through two homeomorphisms, revealing the parametric bifurcation in the payoff matrix. Subsequently, their symbolic dynamics is examined in the context of the snowdrift game, and chaotic characteristics such as nonzero topological entropy and mixing property are derived. These analytical results indicate that even simple interactive elements have diverse dynamical expressiveness to capture the complexity or simplicity of spatial evolutionary games. Therefore, it is recommended that numerical simulations with different parameters should focus on parameter selection, dynamical properties and their combined effects to understand the factors affecting the evolutionary behaviors
Instruments for measuring fatigue in people with rheumatic and musculoskeletal diseases: A systematic review of measurement properties
Get PDFObjective: To summarise the measurement properties of instruments used to assess fatigue in people with rheumatic and musculoskeletal diseases (RMDs). Methods: A systematic review (SR) of measurement properties was conducted in children, adolescents/young adults and adults with RMDs, following Joanna Briggs Institute and COSMIN (COnsensus-based Standards for the selection of health Measurement INstruments) guidelines. Searches were performed in Medline, Embase, CINAHL and Cochrane Library. Risk of bias assessment, data extraction and synthesis were conducted independently by two reviewers. Instruments were assessed according to Outcome Measures in Rheumatology (OMERACT) criteria. Results: Out of 16 657 records, 109 articles underwent full-text review, and 60 met inclusion criteria. These studies evaluated the psychometric properties of 27 instruments. Most studies focused on construct validity (54/60, 90%) and intermethod reliability (45/60, 75%), with an overall low risk of bias. In contrast, test–retest reliability (13/60, 21.7%) and responsiveness (14/60, 23.3%) were less frequently assessed, but also with an overall low risk of bias. Evidence regarding clinical trial discrimination and thresholds of meaningful change was limited or absent, indicating the need for further research in these domains. Only five instruments—the Functional Assessment of Chronic Illness Therapy (FACIT) Fatigue, the 36-Item Short Form Survey Instrument (SF-36) Vitality, the Bristol Rheumatoid Arthritis Fatigue Multi-Dimensional Questionnaire (BRAF-MDQ), the BRAF Numerical Rating Scales (BRAF-NRS) and the Fatigue Severity Scale (FSS)—were rated as valid, reliable and low risk of bias, fulfilling OMERACT endorsement criteria. Conclusions: This SR comprehensively supports the use of several well-validated instruments to assess fatigue, particularly FACIT-Fatigue, SF-36 Vitality, BRAF-MDQ, BRAF-NRS and FSS, in both clinical and research settings. PROSPERO registration number: CRD42024507112
A unified and experimentally validated design framework for long-endurance solar UAVS using model-based multi-objective multidisciplinary optimization
No full textDesigning long-endurance, solar-powered unmanned aerial vehicles (UAVs) requires careful coordination across aerodynamic, structural, and energy subsystems, particularly when targeting flexible, high-aspect-ratio configurations. This paper presents a mission-driven design and optimization framework for solar-powered long-endurance UAVs, tailored to post-disaster urban surveillance scenarios. A modular, multidisciplinary approach is adopted to account for the coupled effects of structural deformation and solar energy availability, both of which critically affect flight endurance. A key feature of the framework is the simultaneous integration of aeroelastic constraints and a time-dependent solar power and battery model, capturing realistic energy generation and storage behavior over diurnal cycles. This energy model is experimentally validated using a custom-built testbed and incorporated directly into the design loop. The framework is implemented using a Multidisciplinary Design Optimization (MDO) architecture that employs a coupling strategy to effectively manage interdependencies among subsystems. A comprehensive sensitivity analysis using Latin Hypercube Sampling highlights key performance-driving parameters. The final UAV design is fabricated and flight-tested, demonstrating the satisfaction of mission-level requirements derived from a simulated post-earthquake damage assessment in Adana, Türkiye. Battery state-of-charge, trajectory, and attitude data collected during flight tests demonstrate that the UAV operates in accordance with design predictions, despite environmental variability. The study highlights how the integration of validated subsystem models within an established optimization process can lead to reliable, application-specific solar UAV designs suitable for real-world deployment
Potential distribution of a noxious weed (Solanum viarum Du-nal), current status, and future invasion risk based on MaxEnt modeling
Get PDFSpecies distribution modeling and niche dynamics of alien plants can aid in understanding theexisting and future invasion potential in the wake of climate change. We describe the nichedynamics of S. viarum Dunal, and report on its present and predicted future distribution inPakistan under scenarios of climate change. The results revealed that S. viarum had anextensive range of prospective distribution zones in Pakistan, with Central Punjab, EasternKhyber Pakhtunkhwa, and Southern Balochistan being the most suitable. According to ROCcurve data, the MaxEnt model has a great prediction precision and credible outcomes. Themost important variables influencing S. viarum latent distribution may be precipitation andtemperature. The current potential area of S. viarum is approximately 105,750 km2 (12%). Underclimate change regimes, the highly suitable area for S. viarum increases by 2–9% under twoRepresentative Concentration Pathways (RCP 4.5 and RCP 8.5). The outcomes of this studycould help to develop control of regional invasions and climate change approaches in Pakistan.More importantly, the findings of niche dynamics in native and invaded S. viarum areascontribute to a better understanding of the nature of niche modifications in invasive speciesand the potential for invasion under climate change
Natural history traits influence winners and losers for herpetological communities in disturbed tropical habitats
Get PDFHabitat alteration can lead to a few ‘winning’ species outcompeting many ‘losing’ species, an effect commonly termed as ‘Winner-Loser-Replacements’ or WLRs. This can lead to homogenisation of species assemblages at phylogenetic and functional levels. Most previous studies analyse responses of species abundance without considering natural history traits associated with those species. This study uses fourth corner modelling techniques to investigate the interaction between ecological data and natural history trait information using a herpetofaunal assemblage that includes 19 species of amphibians, 28 snakes, and 20 lizards, in Parque Nacional Laguna del Tigre, Guatemala. A total of 120 transects were surveyed using Visual Encounter Surveys, comprising 18 in disturbed habitat, 66 in forest habitat, and 36 in edge habitat respectively. Overall, greater diversity of ecological traits was revealed in forest and edge habitats compared to disturbed habitats at the forest edge close to agricultural land. Models revealed that for amphibians (Hypopachus variolosus and Incilius valliceps) and snakes (Coniophanes schmidtii and Leptodeira septentrionalis), association with bare ground, and in the case of amphibians, leaf litter, predicts species persistence in disturbed habitats. Continued forest fragmentation in the region will result in increased edge effects, and a greater proportion of forest remaining in an early successional state, leading to a highly reduced, homogenized, amphibian and reptile assemblage. Using such models for community assemblages of animals to reveal the identity of WLR patterns in forests with continued fragmentation is a useful tool to reveal which species are at risk of impact before habitats become degraded
Towards a unified framework for software-hardware integration in evolutionary robotics
Get PDFThe discrepancy between simulated and hardware experiments, the reality gap, is a challenge in evolutionary robotics. While strategies have been proposed to address this gap in fixed-body robots, they are not viable when dealing with populations and generations where the body is in constant change. The continual evolution of body designs necessitates the manufacturing of new robotic structures, a process that can be time-consuming if carried out manually. Moreover, the increased manufacturing time not only prolongs hardware experimental durations but also disrupts the synergy between hardware and simulated experiments. Failure to effectively manage these challenges could impede the implementation of evolutionary robotics in real-life environments. The Autonomous Robot Evolution project presents a framework to tackle these challenges through a case study. This paper describes the main three contributions of this work: Firstly, it analyses the different reality gap experienced by each different robot or the heterogenous reality gap. Secondly, it emphasizes the importance of automation in robot manufacturing. And thirdly, it highlights the necessity of a framework to orchestrate the synergy between simulated and hardware experiments. In the long term, integrating these contributions into evolutionary robotics is envisioned to enable the continuous production of robots in real-world environments
On oscillations in the external electrical potential of sea urchins
Get PDFSea urchins display complex bioelectric activity patterns, even with their decentralized nervous system. Electrophysiological recordings showed distinct spiking patterns. The baseline potential was about 8.80 mV. It had transient spikes with amplitudes up to 21.05 mV. We observed many types of depolarization events. They included burst-like activity and prolonged state fluctuations lasting several seconds. Frequency domain analysis showed a power-law behavior. It had a scaling exponent of 6.21 ± 0.06, indicating critical dynamics. The analysis showed potential variations between 3.69 and 21.05 mV. The oscillation periods ranged from 4 to 3102 s. The varied timing of bioelectric signals suggests that these organisms can process information. This challenges traditional views of neural computation in simpler animals. These findings provide quantitative insights into the complex signaling mechanisms of the sea urchin’s distributed nervous system
Material mimesis
No full textThis article documents the initial findings of my research into oil-based glazes and the potential for them to be combined with traditional wood engraving. In this project, funded by a UWE Bristol ‘RIS research grant’, I reworked traditional glazing mediums and pigments to create a printing medium suitable for wood engraving. The article outlines the main technical challenges and achievements, such as suitable ingredients, pigment selection and a brief explanation of the science underpinning the technique. The research culminated in the creation of Hera, a large, multi-layered wood engraving that utilizes these glazing inks to replicate the glowing, flesh-like qualities of skin. The work demonstrates the potential of adapting oil painting techniques to the medium of print. This paper not only advances the technical integration of glazing into printmaking but also explores the historical context and artistic implications of using light and opacity to mimic natural materials in art
Virus species names have been standardized; virus names remain unchanged
Get PDFVirus taxonomy, comprising classification and nomenclature, is regulated by the International Committee on Taxonomy of Viruses (ICTV). Taxon names are standardized to facilitate recognition and communication, with defined suffixes for each rank (e.g., the names of orders, families, and genera end in -virales , - viridae, and -virus , respectively). However, until recently, a standard format for species names was lacking. In 2021, following extensive discussion and community consultation, the ICTV decided to adopt a standardized binomial (Linnaean) format for virus species names, consisting of the genus name followed by a “freeform” species epithet. Previously assigned virus species names that were non-compliant with the binomial format have been fully updated. In contrast to taxon names regulated by the ICTV, the names of viruses, or “common” names, such as yellow fever virus or human immunodeficiency virus, are not under the remit of the ICTV and have not been changed