Search Results (4,362)

The coastline is a constantly evolving boundary between land and sea, shaped by natural forces and human activities. Given its significant ecological and economic value, this zone faces increasing pressures, highlighting the need for continuous monitoring and improved understanding to support sustainable management. This study analyses the spatial and temporal changes along the Al Qunfudhah coastline from 1984 to 2020. Using a combination of multi-temporal Landsat satellite images and geographic information system tools—specifically the digital shoreline analysis system—the research tracks changes over time. Shoreline positions were accurately extracted using automated methods, particularly the Canny edge detection algorithm. Over the 36-year period, analysis using the linear regression rate (LRR) and end point rate (EPR) methods revealed a general pattern of slight shoreline advancement. The highest rates of accretion were recorded at 12.43 m/year (LRR) and 13.36 m/year (EPR), with average rates of 3.63 m/year and 4.17 m/year, especially in the northern region where a corniche road was developed along the coast. Conversely, the most significant erosion occurred near the boat port, with maximum rates reaching −24.4 m/year (LRR) and −20.9 m/year (EPR) and average rates of −1.23 m/year and −1.08 m/year. These results offer valuable insights into the factors driving coastal changes and provide a scientific foundation for making informed, sustainable decisions about the future of the Al Qunfudhah coastline. Full article

The paper presents a theoretical reflection on accessibility, developed through dialogue between an architect and a philosopher. It explores the cultural horizon of a transdisciplinary discipline whose conceptual boundaries remain fluid and examines the role accessibility can play in creating a freer and more inclusive society. At the core of the paper lies the concept of accessibility as a Cultural Generative Ecosystem, a dynamic and evolving construct through which accessibility operates as a transformative force. This ecosystem is embedded within a conceptual framework structured around specific Fields of Inquiry (Relational, Spatial, Institutional) and Domains (Person, Society, Environment). In this perspective, accessibility is presented as a complex process rooted in humanistic values and grounded in care ethics, phenomenological experience, and human rights. The paper highlights the potential of accessibility to counter diversity-related discrimination, promote empowerment, and guide the transformation of human habitats in line with people’s needs and expectations. At the same time, it acknowledges the objective and cultural challenges involved in cultivating an accessibility-oriented mindset. Following a comprehensive theoretical and methodological groundwork that lays the foundation for a broader conceptual reframing of accessibility, the paper identifies six conceptual determinants that define its complexity in the built environment, particularly in relation to disability and the relational nature of public space. These determinants—polysemous, contextual, multi-scalar and relational, corporeal and spatial-temporal, multi-criteria, and multi-component—are examined in relation to the four interwoven dimensions that structure the Cultural Generative Ecosystem of accessibility: technical, social, organizational, and generative. Together, they offer a framework for rethinking inclusive design as a situated, relational, and ethically grounded practice. Full article

Drawing from a broad and multifaceted stream of educational research and practice that has gradually emerged in recent decades within science education field, widely known as Inquiry-Based Science Education (IBSE), the current study aims to extend its boundaries within the special education field. In particular it aspires to investigate to what extent teachers foster IBSE characteristics and accommodate the specific learning characteristics of students with autism when they are called to teach them projectile motion and the concept of force. To fulfill this goal, seven secondary school physics teachers with a background in special education were recruited to develop lesson plans on mechanics for high-functioning autistic adolescents. Our findings indicate that these teachers exhibit varying levels of engagement, with certain aspects of IBSE being applied more consistently than others. Notably, the nature of the content appears to play a significant role in shaping this variability. The findings show that teachers tend to demonstrate different levels of engagement, with some aspects of IBSE being more consistently applied than others. Interestingly, the nature of the content appears to play a significant role in influencing this variability. The findings of the current study are likely to contribute to teaching and learning science content to students that with autism spectrum disorder. Full article

The natural frequencies and damping characterisation of a new aerospace grade composite material were investigated using a modified impulse method combined with the half power bandwidth method, which is applicable to the structures with a low damping. The composite material of interest was unidirectional carbon fibre reinforced plastic. The tests were carried out with three identical square 4.6 mm thick plates consisting of 24 plies. The composite plates were clamped along one edge in a SignalForce shaker, which applied a sinusoidal signal generated by the signal conditioner exiting the bending modes of the plates. Laser vibrometer measurements were taken at three points on the free end so that different vibrational modes could be obtained: one measurement was taken on the longitudinal symmetry plane with the other two 35 mm on either side of the symmetry plane. The acceleration of the clamp was also recorded and integrated twice to calculate its displacement, which was then subtracted from the free end displacement. Two material orientations were tested, and the first four natural frequencies were obtained in the test. Damping was determined by the half-power bandwidth method. A linear relationship between the loss factors and frequency was observed for the first two modes but not for the other two modes, which may be related to the coupling of the modes of the plate and the shaker. The experiment was also modelled by using the Finite Element Method (FEM) and implicit solver of LS Dyna, where the simulation results for the first two modes were within 15% of the experimental results. The novelty of this paper lies in the presentation of new experimental data for the natural frequencies and damping coefficients of a newly developed composite material intended for the vibration analysis of rotating components. Full article

Species are disappearing worldwide and the expectation is that this will increase in the future. This review summarizes information on the reasons for the global reduction in biodiversity and what might happen in the future. The literature indicates that the most important factors responsible for this are changes in climate and land use. As changes in land use result in the destruction of natural habitats, they are thought to be the prime driver in the future. Climate change is, however, also often cited as a major driving force. To reduce the effect of climate change on the decline in biodiversity, it is important to know, how climate change affects the abundance and distribution of species. A particular emphasis should be placed not only on conserving specific species but also the environment and communities they live in. In addition, there are many other factors that might play a role, e.g., overexploitation, eutrophication and the introduction and spread of invasive non-native species. Full article

Citrus leaf blotch virus (CLBV) is a positive-sense single-stranded RNA virus belonging to the genus Citrivirus within the family Betaflexiviridae. It infects a broad range of economically significant fruit crops, including citrus, kiwifruit, and apple. Surveys conducted in the field have documented appreciable incidence rates in several hosts, thereby emphasizing its emerging threat to global pomiculture. Comprehensive surveillance of CLBV genetic diversity is indispensable for predicting strain-specific epidemics and designing durable, broadly protective control strategies. Current surveys of CLBV diversity are still gene-fragment-centric, with whole-genome resolution remaining largely untapped. In this study, an analysis of codon usage bias analysis was performed using all available CLBV full-length genomes. The findings revealed that CLBV exhibits low codon usage bias, with natural selection, rather than mutational drift, being the primary driver. Phylogenetic analysis has been demonstrated to categorize isolates according to their host of origin rather than their geographical location. This observation suggests that host adaptation may supersede spatial structure in CLBV evolution and reinforce natural selection as the dominant force shaping its codon usage landscape. From the perspective of the codon adaptation index, Prunus avium is the host that exerts the greatest influence on the formation of its codon usage bias. The present study provides the first genome-wide portrait of CLBV codon usage bias, offering a robust framework for future investigations into its origin and evolutionary dynamics. Full article

This article explores the nature of forced consent in 1950s child adoptions from Greece to the United States. It contributes to critical adoption studies by centering the lesser-known “sending country” of Greece and by drawing from a rare combination of biographical data and testimonies, microhistorical contexts, and otherwise scant archival sources. At stake is the exceptionally well-documented treatment of a Greek birthmother who consented to the overseas adoption of her daughter under conditions of socioeconomic pressure. The article illustrates and denounces the aggressive postwar American approach to child adoption from Greece, which left no room for a strengths-based approach to the dependent nation, let alone to the unwed birthmother. The systemically disempowered birthmother and adopted daughter become paradigmatic of many more such seemingly private but essentially biopolitical adoption processes, which may elude notice for lack of proper documentation. Drawing also on conversations with the affected adoptee in later life, this article further endorses recent child-centered, diachronic historical methods and interdisciplinary approaches, as well as a call for truth and reconciliation. Full article

Cerebral aneurysm clipping remains a key surgical approach despite advancements in endovascular techniques. However, training for this procedure is complex due to the variable and fragile nature of aneurysmal tissues. This study evaluates the mechanical behaviour of human basilar arteries during clipping and compares them to 3D-printed models used for neurosurgical training. Mechanical tests were performed on ten cadaveric basilar arteries, distinguishing between healthy and plaque-affected segments. Plaque-affected regions required significantly higher clipping force (1.73 ± 0.22 N) compared to healthy segments (0.45 ± 0.19 N), confirming that atherosclerosis markedly increases arterial stiffness. Six 3D-printed phantom materials were evaluated; none accurately replicated the biomechanical response of real arteries. The Flex Anatomical material showed the highest stiffness (44.51 ± 0.98 N), while Silicone 40A was the most compliant (1.05 ± 0.12 N), yet both deviated substantially from biological performance. These findings underscore the current limitations of anatomical models that lack realistic biomechanical properties. Full article

This paper analyzes the physics of the TMD-Inerter for harmonic vibrations. The basic TMD-Inerter layout is assumed, where the inerter is installed between the TMD mass and the structural mass. For harmonic vibrations, the inerter force can be formulated as a function of terminal displacements. This formulation demonstrates that the inerter force is, in fact, a negative stiffness force with frequency-dependent negative stiffness coefficient. Based on this finding, the optimal stiffness tuning of the TMD-Inerter is derived. As this stiffness tuning can only be realized by a controlled actuator, the tuning of the spring of the TMD-Inerter is presented. As this spring is a passive element, its optimum tuning must be made at a selected frequency of vibration. It is shown that the average of the TMD natural frequency and structural eigenfrequency leads to a close to optimal spring tuning. This approach needs to be combined with increased damping of the TMD-Inerter to minimize the structural displacement response. Despite the close to optimal tunings of stiffness and damping, the resulting primary structure displacement response is approximately 41.6% greater than that due to the classical TMD. The reason for this lies in the fact that the passive spring of the TMD-Inerter cannot compensate for the frequency-dependent negative stiffness of the inerter within the entire frequency range. Full article

The increasing demand for sustainable engineering solutions has driven extensive research into natural fibre-reinforced composites (NFCs), notably flax fibre-reinforced polymers (FFRPs), which offer promising eco-friendly alternatives to synthetic composites. This study presents a comprehensive application of continuum damage mechanics (CDM) methodology to unidirectional (UD) FFRPs, addressing critical gaps in predictive modelling of progressive intralaminar damage for sustainable structural applications. A systematic experimental characterisation protocol was developed to identify material parameters that account for the inherent variability and complex nonlinear behaviour of natural fibres. The CDM model was calibrated using comprehensive quasi-static testing on multiple laminate configurations and validated through finite element analysis (FEA) in Siemens Simcenter Samcef. The model accurately captures the nonlinear behaviour and damage mechanisms of notched flax–epoxy laminates, achieving prediction accuracies of 97.61% and 88.98% for the force-displacement response in open-hole tensile (OHT) validation tests. Integrating experimental characterisation with FEA enables robust virtual prototyping of sustainable composite structures, supporting design optimisation and lifecycle assessment. This research establishes validated damage modelling methodologies for eco-friendly NFC, facilitating accelerated adoption in automotive, marine, and construction sectors. Full article

This study presents an analysis of transverse vibration behavior of a fluid-conveying pipe mounted on an elastic foundation, incorporating both classical analytical techniques and modern physics-informed neural network (PINN) methodologies. A partial differential equation (PDE) architecture is developed to approximate the solution by embedding the physics PDE, initial, and boundary conditions directly into the loss function of a deep neural network. A one-dimensional fourth-order PDE is employed to model governing transverse displacement derived from Euler–Bernoulli beam theory, with additional terms representing fluid inertia, flow-induced excitation, and stochastic force modelled as Gaussian white noise. The governing PDE is decomposed via separation of variables into spatial and temporal components, and modal analysis is employed to determine the natural frequencies and mode shapes under free–free boundary conditions. The influence of varying flow velocities and excitation frequencies on critical buckling behavior and mode shape deformation is analyzed. The network is trained using the Resilient Backpropagation (RProp) optimizer. A preliminary validation study is presented in which a baseline PINN is benchmarked against analytical modal solutions for a fluid-conveying pipe on an elastic foundation under deterministic excitation. The results demonstrate the capability of PINNs to accurately capture complex vibrational phenomena, offering a robust framework for data-driven modelling of fluid–structure interactions in engineering applications. Full article

Global ecosystems have undergone significant degradation and deterioration, making the identification of ecosystem changes essential for promoting sustainable development and enhancing quality of life. Hami City, a representative region characterized by the complex “desert–oasis–mountain” ecosystem in Xinjiang, China, provides a critical context for examining ecosystem changes in extremely arid environments. This study utilizes remote sensing data alongside the Revised Wind Erosion Equation and Revised Universal Soil Loss Equation models to analyze the transformations within the desert–oasis ecosystems of Hami City and their driving forces. The findings reveal that (1) over the past 24 years, there have been substantial alterations in the ecosystem patterns of Hami City, primarily marked by an expansion of cropland and grassland ecosystems and a reduction in desert ecosystems. (2) Between 2000 and 2023, there has been an upward trend in Fractional Vegetation Cover, Net Primary Productivity, and windbreak and sand fixation amount in Hami City, whereas soil retention has shown a declining trend. (3) The overall ecosystem change in Hami City is moderate, encompassing 61.85% of the area, with regions exhibiting positive change comprising 16.79% and those with negative change comprising 21.33%. (4) Temperature, precipitation, and evapotranspiration are the primary drivers of ecosystem change in Hami City. Although the overall changes in ecosystems in Hami City have shown an improving trend, significant spatial heterogeneity still exists. The natural climatic conditions of Hami City constrain the potential for further ecological improvement. This study enhances the understanding of ecosystem change processes in extremely arid regions and demonstrates that strategies for mitigating or adapting to climate change need to be implemented as soon as possible to ensure the sustainable development of ecosystems in arid areas. Full article

Inspired by the structural characteristics of natural spider webs, a simplified configuration composed of multi-layer regular polygons was developed to design a novel energy absorbing component for legged landers. To investigate its compressive energy-absorption behavior, a parameterized finite element model (FEM) was established. By integrating optimized Latin hypercube experimental design with the FEM, the energy absorption characteristics under varying structural parameters were evaluated. Based on the FEM results, response surface methodology was employed to construct surrogate models that capture the mapping relationships between design parameters and performance indices. Using these surrogate models, the energy-absorbing component was optimized under three different ranges of average buffering force. Three optimized components with distinct average buffering forces were selected and connected in series, and their force–displacement responses during compression were computed through finite element simulations. The obtained response curves were incorporated into a multibody dynamics model of a Mars lander to verify performance, demonstrating that the lander can achieve effective soft landing. Full article

Background: Attentional focus strategies, including internal, external, and sport-specific cues, can influence muscle strength by modulating motor control. However, their acute effects on maximal isometric back-extensor strength in youth athletes under controlled laboratory conditions remain unclear. Methods: Fourteen youth golfers (15.8 ± 0.5 years) performed maximal voluntary isometric back-extension tasks under nine cueing conditions: three internal, three external, and three golf-specific. The task involved exerting maximal force against a fixed, immovable resistance while maintaining standardized trunk and hip positions to ensure consistent execution. Cueing was delivered verbally in a standardized manner across participants and sessions. Maximal isometric strength was compared across conditions using repeated-measures analyses. Results: Maximal isometric back-extensor strength was significantly (p = 0.004 η_p² = 0.34) lower with internal cues (57.1 ± 16.0 kg) compared with external (68.2 ± 13.0 kg) and golf-specific (68.1 ± 12.5 kg) cues. Specifically, the internal cues ‘engage your glutes and hamstrings’, ‘tighten your core’, and ‘maintain a neutral spine’ produced lower force than all external cues and the golf-specific cue ‘focus on using your lower body to create a stable base for your golf swing’. Among internal cues, ‘engage your glutes and hamstrings’ resulted in the lowest torque. Conclusions: External and certain golf-specific verbal cues acutely enhance maximal isometric back-extensor force more effectively than internal cues in a controlled laboratory setting. While these results inform how attentional focus can modulate acute force output in youth athletes, the task does not replicate the dynamic, rotational nature of the golf swing, and the findings should not be interpreted as direct indicators of golf performance. Future research should explore long-term adaptations and assess transfer to sport-specific, dynamic movements. Full article

Generalized frosts have a significant impact on the Pampa Húmeda of Argentina, particularly those without persistence (0DP), defined as events that do not last more than one day, and are the most frequent generalized frosts. This study investigates the dynamical and physical mechanisms that sustain these events, emphasizing the nonlinear interactions represented by the Rossby Wave Source (RWS) equation. Composite analysis of pressure, temperature, wind and geopotential height fields were performed, showing that 0DP events are related to abrupt cold air intrusion linked to the enhancement of upper levels troughs over the eastern Pacific Ocean and transient surface anticyclones over South America. This linear analysis only showed a lack of persistent upper-level maintenance and did not explain the dynamics of the rapid weakening of the circulation. For this reason, a nonlinear analysis based on the decomposition of the RWS equation into its advective and divergent terms is performed. The advective term only acts as an initial trigger, deepening troughs and favoring meridional cold air advection, while the divergent term dominates the events, representing 63–67% of the affected area. This term reinforces ridges, promotes subsidence and favors clear sky conditions that enhance nocturnal radiative cooling and frost formation. Positive anomalies of the divergent RWS term strengthen the ridge and advect cold air over the Pampa Húmeda, whereas subsequent negative anomalies over the southwestern Atlantic act as sinks of wave activity, leading to the rapid dissipation of the synoptic configuration. Consequently, the same mechanism that generates favorable conditions for frost development also determines their lack of persistence. These findings demonstrate that the short-lived nature of 0DP frosts is not due to the absence of dynamical forcing, but rather to nonlinear processes that both enable and constrain frost occurrence. This highlights the importance of incorporating nonlinear diagnostics, such as the RWS, to improve the understanding of short-lived atmospheric extremes. Full article