Search Results (117)

This study presents an iconographic analysis of cylinder seals from the British Museum’s collection belonging to ancient Near Eastern cultures that depict big cats. A total of 542 cylinder seals were examined, from which 171 big cat representations on 101 seals were selected as the sample. The sample was analyzed using the visual analysis method. Data obtained from the analyses were coded with the MAXQDA 2024, version 24.7 software, thematic and sub-thematic categories were established, and content analysis was conducted. The results indicate that only one of the big cat figures can be identified as a leopard, while the remainder represent lions. In terms of formal characteristics, lion figures predominate, followed by hybrid forms such as griffin-lions. Most of the big cats are depicted standing upright on their hind legs with open mouths in aggressive or attacking postures, emphasizing the lion’s ferocity. The figures are generally highly stylized and possess strong representational qualities. Lions also appear in protective forms, such as sphinxes and griffins, symbolizing strength and guardianship. Additionally, heroes and rulers shown defeating lions function as visual expressions of political authority. Overall, big cat imagery on cylinder seals served as a symbolic medium conveying power, authority, protection, and sacredness within ancient societies. Full article

This study applies SR within an XAI framework to develop interpretable, white-box models for predicting P₅₀ in rock fragmentation by blasting. The dataset comprised 221 observational subsets from 63 blasts across 16 quarries and 23 lithological units in northwestern Türkiye. Repeated PySR searches yielded four equation families of varying complexity. The best-performing model, incorporating ρ, σ_c, D₅₀, q, and VoD, achieved a high R² and low error metrics on the independent test set. This model significantly outperformed the empirical formulations and closely matched the predictive performance of black-box machine learning tools, while retaining a fully explicit and verifiable mathematical structure. Equations derived from the FDM produced more consistent predictions across the broad range of operational and geological conditions in the database. In contrast, equations derived from the LWM subset—constrained by recommended parameter ranges—performed well within their calibration domain but showed greater sensitivity to extrapolation. The turning points in the model responses were consistent with rock mechanics and blasting principles; however, they are interpreted as testable hypotheses requiring independent validation rather than confirmed physical thresholds. Overall, the study demonstrates the ability of SR to transform complex field observations into transparent empirical relationships between blasting parameters, rock mass properties, and fragmentation outcomes. Nonetheless, these equations remain candidate relationships derived from the present dataset and require independent validation before practical implementation. Full article

We present a short-preamble digital signal processing (DSP) architecture for downstream Alamouti coherent-lite passive optical network (PON) reception using a simplified optical network unit (ONU) receiver. A four-branch gear-shifted least-mean-square (LMS) equalizer uses a large step during quadrature phase-shift keying (QPSK) preamble training and a small step during decision-directed payload tracking. In 50 GBaud 16-ary quadrature amplitude modulation (16-QAM) simulations over 20 km single-mode fiber, a 2048-symbol preamble is the first cold-start point whose mean bit-error rate (BER) falls below the selected uncoded BER target of ${10}^{-2}$. A 20-realization-per-point sweep gives a sub-1 dB penalty for 2048 symbols and a mean offline mean-square-error (MSE) settling time below 100 ns, with low-gain locking events retained. However, frame-level reliability improves with longer training: in an indicative 20-frame Monte Carlo test, 13 of 20 frames met the BER target with a 2048-symbol preamble, compared with 17 of 20 using 4096 symbols. For repeated frames to the same ONU after initial acquisition, warm-start tap reuse allows frames 4–5 in the tested sequence to fall below target with 512-symbol preambles, corresponding to a later-frame nominal coded payload rate of 163 Gb/s instead of 123 Gb/s. The results quantify the preamble/reliability/payload-rate trade-off and indicate that downstream Alamouti coherent-lite reception can support short-training equalizer acquisition after preamble synchronization with one balanced detector and one analog-to-digital converter. Full article

This paper explores the culinary and cultural significance of cooked leafy vegetables among Afro-descendant communities in French Guiana and Suriname, including French Guianese and Surinamese Creoles, Maroons, and Haitian migrants. While leafy greens play a major dietary role across sub-Saharan Africa, their consumption in the Americas remains understudied. This ethnobotanical study of edible leafy plants is based on surveys of local markets, gardens and residents. Drawing on 26 informal interviews conducted in four local languages (French, French Guianese Creole, Haitian Creole, and Nengee Tongo), we describe 36 species of edible leaves from 20 plant families consumed in the region. Our findings show that although the practice of eating leafy greens is widely shared, the species selected, their names, and their perceived properties vary noticeably across cultural groups. Some plants are eaten exclusively by Maroons (e.g., Cestrum latifolium, Capsicum spp.), others by Haitians (e.g., Corchorus olitorius, Rivina humilis), and some have fallen into disuse among younger generations. These differences are shaped by ecological availability, cultural memory, food-medicine beliefs, and interethnic influences. We suggest that the term callaloo (referring to both dishes and leafy vegetables), which circulates in multiple linguistic and culinary forms throughout the African diaspora, can serve as a metaphor for the interculturalization of foodways. More than ingredients, these leafy vegetables act as dynamic cultural markers—symbols of resilience, transmission, and transformation. In a context of rapid globalization, where unseen foods risk sinking further into obscurity, these plant-based traditions highlight both the adaptability and fragility of Afro-descendant culinary heritage in the Guiana Shield. Full article

A low-latency, low-complexity digital demodulator is presented for chirp spread spectrum (CSS)-modulated RF packets targeting low-power IoT wireless systems operating in spectrally congested environments. Conventional CSS receivers rely on fast-fourier transform (FFT)-based synchronization and long preamble sequences, resulting in increased latency and computational complexity. To address these limitations, the proposed receiver employs amplitude-domain synchronization using oversampled sub-chirp windows and maximum likelihood estimation without requiring FFT processing. A digital demodulator co-designed with receiver’s fractional-N phase-locked loop (PLL) architecture enables rapid sub-chirp generation and fast frequency settling, while compensation techniques mitigate symbol boundary offset (SBO) error due to PLL non-idealities during synchronization. The proposed system achieves packet synchronization within 17.5 preamble symbol cycles while maintaining symbol boundary offset estimation error below ±1%. Simulation results demonstrate a syncword misdetection probability below 10⁻³ at SNRs of 9 dB and 1 dB without and with 8× repetition, respectively. In the presence of interferences, the receiver tolerates worst-case in-band signal-to-noise ratio (SIR) levels down to −16.2 dB while consuming 877 µW and 830 µW average power at the digital demodulator, and fractional-N PLL, respectively. Implemented in 65 nm CMOS, the proposed architecture occupies 0.195 mm² active area. Full article

This study aims to examine whether and how environmental, social, and governance (ESG) performance is related to corporate tax avoidance in a non-linear and threshold-dependent manner using explainable machine learning. Based on 6461 firm-year observations of publicly listed European firms over the 2018–2023 period, this study employs a multi-algorithmic machine-learning classification framework. Model interpretability is achieved through SHAP, which identifies feature importance, marginal effects, interaction patterns, and ESG-related threshold dynamics. The results demonstrate that the ESG–tax relationship is highly non-linear. While the Country and Industry factors establish baseline tax risks, ESG sub-dimensions act as critical firm-level determinants. Specifically, high Corporate Social Responsibility (CSR) and Human Rights scores effectively constrain tax avoidance. In contrast, exceptionally high Management scores correlate with increased tax-avoidance risk. These findings support the legitimacy buffer argument and show that strong governance may also reflect managerial sophistication and capacity for less visible tax planning. The study contributes by revealing non-linear ESG threshold effects and by demonstrating how XAI/SHAP can distinguish between symbolic and substantive sustainability practices in corporate tax behavior. Full article

Using theories of Afrocentricity (African Indigenous Knowledge) and of positioning, we investigated how Sub-Saharan African immigrant parents (SSAIP) support their Grade 6–9 children’s mathematics learning in Canada. Individual interviews were collected from twelve immigrant parents living in an urban community in Alberta and new to Canada (within five years). We ask: what are the mathematics experiences and perspectives of Sub-Saharan African immigrant families? We analyzed interview data from 12 SSAIPs from Greater Edmonton, Canada to identify the storylines they shared regarding their experiences and perspectives of mathematics learning. The prevailing storylines were interpreted through an African Indigenous Knowledge lens. We found that parents adjust their mathematics learning support for their children by negotiating their experiences from two cultural worlds of education: pre-colonial (African Indigenous Knowledge) and colonized worldviews, their home and host cultures, generally. We identified these storylines, some of which sit in tension with each other: “mathematics learning is a communal responsibility”, “mathematics teachers share responsibility for the moral upbringing of the child”, “mathematics as memory work is feared and stressful”, “adults tell children what to do”, “adults negotiate with children about what to do”, and “success in mathematics is a gift from God”. We interpreted the storylines through the Akan Adinkra epistemologies which manifest in the Adinkra symbols and sayings, and through our experiences living and working in Sub-Saharan Africa, to determine the way each storyline aligned with old African or new African ways. This study will be beneficial for educators wishing to adopt culturally responsive ways of engaging immigrant families in their children’s mathematics learning. Full article

This study examines the dynamical behavior of the dual-mode nonlinear Schrödinger equation (d-mNLSE), which describes the interaction, amplification, and attenuation of two coexisting wave modes in nonlinear media. The model incorporates key physical parameters including the nonlinearity coefficient, interaction phase velocity, and dispersion parameter, which significantly influence the evolution of nonlinear waves. By applying the modified Sardar sub-equation method (mSS-EM), a wide spectrum of exact analytical solutions is derived. These solutions include mixed trigonometric waves, shock-type structures, singular solutions, complex dark–bright solitons, multi-peak solitons, periodic and mixed-periodic waves, as well as mixed hyperbolic structures. The analytical findings provide useful insight into nonlinear wave propagation phenomena arising in fluid mechanics, water wave dynamics, ocean engineering, and related physical systems. Moreover, the conservation laws of the d-mNLSE are established, which leads to the conserved quantities of impulse power, momentum, and energy and describes the invariant characteristics of the soliton solutions during their propagation. The bifurcation analysis of the reduced dynamical model is carried out to explore the qualitative characteristics of the obtained solutions. The equilibrium points of the considered model are calculated, and their stability properties are analyzed systematically. To demonstrate the physical characteristics of the obtained solutions, different kinds of two-dimensional, three-dimensional, and contour plots are plotted using symbolic computations software. These findings confirm that the analytical method used to obtain the soliton solutions can be used to obtain a variety of soliton solutions of nonlinear evolution equations that appear in applied sciences and engineering. Full article

Previous research on Internet altruistic behavior (IAB) has primarily focused on helpers. However, as a form of prosocial behavior embedded in online interpersonal interaction, IAB is likely shaped by characteristics of both helpers and seekers. Accordingly, the present research integrated attachment theory and social information processing models to examine how helper-related factors (secure attachment and positive empathy) and seeker-related factors (emoji symbols) influence IAB, as well as the mechanisms underlying these effects. Three studies were conducted. Study 1 used a one-factor between-subjects design to examine the effect of secure attachment on IAB. Study 2 employed an experimental causal-chain approach with three sub-studies to test the causal links among secure attachment, positive empathy, and IAB. Study 3 used a 2 (positive empathy: high vs. low) × 2 (emoji: present vs. absent) between-subjects design to examine whether seekers’ emoji use moderated the relationship between helpers’ positive empathy and IAB. The results showed that individuals with higher (vs. lower) secure attachment engaged in more IAB, and that positive empathy mediated the relationship between secure attachment and IAB. In addition, seekers’ emoji use significantly moderated the relationship between helpers’ positive empathy and IAB. Specifically, this moderation was antagonistic: the presence of emoji was associated with a weaker, rather than stronger, positive relationship between positive empathy and IAB. Nevertheless, overall levels of IAB were higher in messages containing emoji. These findings provide a more comprehensive understanding of the antecedents of IAB and offer practical implications for promoting altruistic behavior in online contexts. Full article

To meet the demand for high-capacity indoor wireless access in future 6G systems, we propose and experimentally demonstrate a photonics-aided D-band wireless transmission scheme operating at 138 GHz. At the transmitter, two external-cavity lasers together with an I/Q modulator are used to generate a modulated D-band carrier. At the receiver, homodyne down-conversion is employed to directly recover the received signal to baseband, thereby relaxing the requirements on ultra-wideband analog components and high-speed sampling hardware. A 20 m indoor line-of-sight wireless link is established to transmit a 56-Gbaud-rate OFDM-QPSK signal. The transmitted and received spectra, received constellations and bit-error-rate (BER) performance are functions of optical power at different symbol rates, and the channel amplitude and phase responses are systematically analyzed. The results show that broadband D-band signal generation, transmission, and recovery can be stably achieved in the proposed system. After receiver-side digital signal processing (DSP), clear QPSK constellations are obtained. BER measurements reveal an optimal optical-power operating range, and the 32-GBaud OFDM signal outperforms the 56-Gbaud-rate signal because its narrower occupied bandwidth makes it less sensitive to frequency-selective distortion. For 56-Gbaud-rate OFDM transmission, the BER approaches the 20% low-density parity-check forward-error-correction threshold at an optical power of approximately −1 dBm. Further analysis indicates that the current link performance is mainly limited by frequency-selective amplitude and phase distortions under bandwidth-constrained conditions, together with slight nonlinear effects at high power. These results verify the feasibility of a photonics-aided D-band wireless architecture with homodyne reception for medium-range, high-symbol-rate indoor transmission and provide an experimental basis for future 6G sub-THz wireless links. Full article

This study applies Pierre Bourdieu’s field theory as an analytical framework to examine the development of Peking opera along the Beijing Central Axis during the Qing Dynasty. It explores how the interaction between the court and folk fields contributed to the formation of its artistic form. From this perspective, social space is understood as a structured network of objective relations, shaped by the distribution of different forms of capital and the habitus of social actors. In the Qing Dynasty, as the core of political and cultural activities, the Peking opera field along the Beijing Central Axis was divided into two major sub-fields: the court field, centered around imperial power and subject to political discipline, and the folk field, market-oriented and following secular logic. By analyzing the differences between the two fields in terms of core power, spatial characteristics, capital distribution, and the habits of actors, this study reveals their two-way interaction achieved through the movement of artists, adaptation of repertoires, and capital conversion. The interaction between the two fields was not symmetrical: while the folk field contributed performative vitality and responsiveness to audience demand, the court provided institutional authority and symbolic legitimacy. Ultimately, in the dynamic balance between power and the market, the unique form of Peking opera, characterized by the integration of elegance and vulgarity, is refined. This study deepens our understanding of the interaction between spatial organization and artistic form, while further elucidating how power, culture, and art were structurally interconnected in the Qing Dynasty through the framework of field, capital, and habitus. In doing so, it offers both theoretical insights and empirical evidence for interdisciplinary research on the social and cultural functions of traditional art. Full article

Background: Sleep disturbance is highly prevalent in dementia syndromes and increasingly viewed as a correlate of disease expression, not just ageing. This study investigated associations between subjective sleep quality, cognitive performance, and structural MRI markers in a dementia syndromes sample, comparing Alzheimer’s disease (AD) and non-AD groups, with exploratory inclusion of objective sleep and nocturnal blood pressure in a sub-sample. Methods: Observational cross-sectional design with 128 memory clinic patients (41 AD, 87 non-AD). Subjective sleep quality assessed via Pittsburgh Sleep Quality Index (PSQI). Cognitive measures: Mini-Mental State Examination (MMSE) for global cognition, Symbol Digit Modalities Test (SDMT) for processing speed, Trail Making Tests (TMT-A/B), and CLOX-1/2 for executive function. MRI markers: Scheltens scale (medial temporal atrophy), Fazekas scale (white matter hyperintensities). An exploratory sub-sample (N = 24) included additional nocturnal and daytime blood pressure monitoring; these data were analyzed descriptively and are reported as hypothesis-generating only. Analyses: group comparisons, Spearman correlations, hierarchical and logistic regression models in the full sample, and descriptive analyses with Spearman correlations in the exploratory sub-sample. Results: The AD group reported poorer sleep quality (higher PSQI) and worse cognitive performance across domains compared with the non-AD group (p < 0.001). Higher PSQI scores were associated with poorer cognitive outcomes, particularly executive function and processing speed, after adjustment for demographics and structural MRI markers (e.g., β = −0.181 to −0.425 for MMSE/SDMT). In the exploratory sub-sample (N = 24), PSQI was correlated with SDMT (ρ = −0.653) and TMT-A (ρ = 0.788). Conclusions: Subjective sleep quality was associated with cognitive performance in individuals with dementia syndromes after accounting for structural MRI markers. These findings suggest that subjective sleep disturbance may represent a complementary clinical dimension warranting further longitudinal research, including evaluation of whether sleep-focused interventions may offer clinical benefits. Full article

Reconfigurable intelligent surfaces (RISs) are regarded as a transformative technique for future wireless networks. Currently, the majority of research efforts have focused on channel estimation scenarios in communication systems assisted by a single passive RIS. However, single-RIS-assisted systems suffer from limited coverage performance, with significant performance degradation observed in dense obstacle environments. To mitigate the adverse impacts imposed by environmental factors, a dual-RIS-assisted communication system exhibits superior adaptability to practical scenarios. This work focuses on investigating such a system. It is worth noting that fully passive RISs lack the capability to process signals independently. Furthermore, when employing pilot-aided algorithms to acquire channel state information (CSI), wireless systems often encounter challenges arising from large channel matrix dimensions, thereby leading to substantial pilot overhead. To address the aforementioned issues, this paper proposes a novel semi-blind channel estimation method for multiple-input multiple-output (MIMO) systems aided by double reconfigurable intelligent surfaces (D-RISs). Specifically, we construct two tensor models, namely the Parallel Factor (PARAFAC) model and the Parallel Tucker2 model, for the received signal in two separate stages. By means of tensor decomposition, the joint channel estimation and symbol detection problem is reformulated as a least squares problem and solved using a two-stage algorithm. In the first stage, the ALS algorithm is adopted to estimate the transmitted symbols and provide initialization for the second stage. Then, in the second stage, the TALS algorithm is employed to obtain the final estimation results of the three sub-channels. Simulation results verify the effectiveness of the proposed receiver. Full article

Multipath propagation presents a major challenge to acoustic communication, causing signal distortion, delay spread, and inter-symbol interference, which degrade data integrity. This study investigates the use of Orthogonal Frequency Division Multiplexing (OFDM) as a robust modulation strategy for communication in complex acoustic environments where radio frequency (RF) propagation is severely attenuated. Using a software-defined radio (SDR) platform implemented in GNU Radio, OFDM performance was experimentally evaluated against Binary Frequency Shift Keying (BFSK) and Binary Phase Shift Keying (BPSK) under simulated and real multipath conditions in materials including air, water, and steel. The results show that OFDM achieves consistently lower bit error rates (BERs) and greater resilience to multipath interference due to its sub-carrier orthogonality and cyclic-prefix structure. The research also highlights how the frequency selectivity and coherence bandwidth of acoustic channels influence modulation performance across different media. By implementing custom transducers and real-time baseband processing, the study demonstrates how software-defined acoustics can be adapted for highly reflective and frequency-dependent environments. The observed improvements in BER and signal stability validate OFDM’s effectiveness in maintaining data integrity despite time and frequency dispersion effects. These findings demonstrate that OFDM enables reliable acoustic data transmission across heterogeneous media and is well suited to sensor-network applications in RF-hostile environments such as railway infrastructure, sealed containers, and submerged systems. Future work will include quantitative channel characterisation—specifically measuring delay spread, coherence bandwidth, and impulse response profiles—to further optimise OFDM parameters and provide a generalisable framework for adaptive modulation in dynamic acoustic channels. Full article

This work investigates the nonlinear flexural dynamics of a macroscale cantilever beam by combining analytical modeling, symbolic solution techniques, numerical simulation, and vision-based experiments. Starting from the Euler–Bernoulli equation with geometric and inertial nonlinearities, a reduced-order model is derived via a single-mode Galerkin projection, justified by the experimentally confirmed dominance of the fundamental bending mode. The resulting nonlinear ordinary differential equation is solved analytically using two symbolic methods rarely applied in structural vibration studies: the Extended Direct Algebraic Method (EDAM) and the Sardar Sub-Equation Method (SSEM). Comparison with high-accuracy numerical integration shows that EDAM reproduces the nonlinear waveform with high fidelity, including the characteristic non-sinusoidal distortion induced by mid-plane stretching. High-speed vision-based measurements provide displacement data for a physical cantilever beam undergoing free vibration. After calibrating the linear stiffness, analytical and experimental responses are compared in terms of the dominant oscillation frequency. The analytical model predicts the classical hardening-type amplitude–frequency dependence of an ideal Euler–Bernoulli cantilever, whereas the experiment exhibits a clear softening trend. This contrast reveals the influence of real-world effects, such as initial curvature, boundary compliance, or micro-slip at the clamp, which are absent from the idealized formulation. The combined analytical–experimental framework thus acts as a diagnostic tool for identifying competing nonlinear mechanisms in flexible structures and provides a compact physics-based reference for reduced-order modeling and structural health monitoring. Full article