Search Results (715)

Economic growth, especially in emerging economies, has altered the composition of international tourism. It is therefore essential to possess the skills necessary to understand the influence of culture on human behaviour, thereby enabling an appropriate response to the traveller. This research aims to develop a tool for identifying openness, flexibility, awareness, and intercultural preparedness. It focuses on the metacognitive and cognitive aspects of cultural intelligence that shape the development of empathy in customer service staff in hotels in Quintana Roo. The variables were validated and incorporated into a quantitative study using multivariate analysis and inferential statistics. A sample of 77 questionnaires was analysed using simple random sampling under a proportional design. Multiple Correspondence Analysis (MCA) was employed as a discriminatory technique to identify the most significant independent variables. These were subsequently entered as regressors into ordinal logistic regression (OLR), along with age and work experience, in order to estimate the probabilities associated with each level of the dependent variable. The results indicated that age had minimal influence on the metacognitive and cognitive variables, whereas years of experience among tourism staff exerted a significant effect. Full article

Background: Human activity is recognised as a major contributor to changes in Earth’s climate, land surface, oceans, ecosystems, and biodiversity. These alterations are largely due to greenhouse gas emissions, deforestation, mass pollution, and land degradation. In light of these environmental challenges, examining the psychological determinants of pro-environmental behaviour has become increasingly important. Study’s Aim: To provide a comprehensive model evaluating the structural relationships among biospheric values, green self-identity, green self-efficacy, and eco-anxiety to investigate the underlying mechanisms relating to the adoption of various pro-environmental behaviours (PEBs). Methods: An online self-report questionnaire was completed by 510 Italian participants (aged 18–55, M = 35.18, SD = 12.58) between November and December 2023. Data analysis was performed using R statistical software, employing Structural Equation Modelling. Results: The results indicate that eco-anxiety, green self-efficacy, and green self-identity are significant positive predictors of PEBs. Furthermore, green self-identity significantly influences eco-anxiety and green self-efficacy, while biospheric values are a major trigger for both green self-efficacy and green self-identity, but not for eco-anxiety. Conclusions: These findings suggest that while eco-anxiety can be an adaptive motivator for PEBs, biospheric values foster a green self-identity and self-efficacy, which in turn drive pro-environmental actions. The study concludes that encouraging biospheric values and strong green self-identity is crucial for promoting sustainable behaviours. Full article

We study the behaviour of the chameleon mechanism around white dwarfs and its impact on their structure. Using a shooting method of our own design, we solve the corresponding scalar–tensor equilibrium equations for a Chandrasekhar equation of state, exploring various energy scales and couplings of the chameleon field to matter. For the considered parameter ranges, we find the chameleon field to be in a thick-shell configuration, identifying for the first time in the literature a similarity relation of the theory for the radially normalised scalar field gradient. Our analysis reveals that the chameleon mechanism alters the pressure gradient of white dwarfs, leading to a reduction in the stellar radii and masses and shifting the mass–radius curves below those predicted by Newtonian gravity. This also lowers the specific heat of white dwarfs, accelerating their cooling process. Finally, we derive parametric expressions from our results to expedite future analyses of white dwarfs in scalar–tensor theories. Full article

This work addresses for the first time the effect of anode serpentine channel depth on Methanol Electrolysis Cells (MECs) and Direct Methanol Fuel Cells (DMFCs) for improving performance of both devices. Anode plates with serpentine flow fields of 0.5 mm, 1.0 mm and 1.5 mm depths are designed and tested in single-cells to compare their behaviour. Performance was evaluated through methanol crossover, polarization and power density curves. Results suggest shallower channels enhance mass transfer efficiency reducing MEC energy consumption for hydrogen production at 40 mA∙cm⁻² by 4.2%, but increasing methanol crossover by 30.3%. The findings of this study indicate 1.0 mm is the best depth among those studied for a MEC with 16 cm² of active area, while 0.5 mm is the best for a DMFC with the same area with an increase in peak power density of 14.2%. The difference in results for both devices is attributed to higher CO₂ production in the MEC due to its higher current density operation. This increased CO₂ production alters anode two-phase flow, partially hindering the methanol oxidation reaction with shallower channels. These findings underscore the critical role of channel depth in the efficiency of both MEC and DMFC single-cells. Full article

Background: Borderline personality disorder (BPD) is a severe psychiatric condition characterised by emotional instability, impulsivity, interpersonal dysfunction, and self-injurious behaviours. Despite growing clinical interest, the neuropsychological mechanisms underlying these symptoms are still not fully understood. This review aims to summarise findings from neuroimaging, psychophysiological, and neurodevelopmental studies in order to clarify the neurobiological and physiological basis of BPD, with a particular focus on emotional dysregulation and implications for the treatment of adolescents. Methods: A narrative review was conducted, integrating results from longitudinal neurodevelopmental studies, functional and structural neuroimaging research (e.g. FMRI and PET), and psychophysiological assessments (e.g., heart rate variability and cortisol reactivity). Studies were selected based on their contribution to understanding the neural correlates of BPD symptom dimensions, particularly emotion dysregulation, impulsivity, interpersonal dysfunction, and self-harm. Results: Findings suggest that early reductions in amygdala volume, as early as age 13 predict later BPD symptoms. Hyperactivity of the amygdala, combined with hypoactivity in the prefrontal cortex, underlies deficits in emotion regulation. Orbitofrontal abnormalities correlate with impulsivity, while disruptions in the default mode network and oxytocin signaling are related to interpersonal dysfunction. Self-injurious behaviour appears to serve a neuropsychological function in regulating emotional pain and trauma-related arousal. This is linked to disruption of the hypothalamic-pituitary-adrenal (HPA) axis and structural brain alterations. The Unified Protocol for Adolescents (UP-A) was more effective to Mentalization-Based Therapy for Adolescents (MBT-A) at reducing emotional dysregulation compared, though challenges in treating identity disturbance and relational difficulties remain. Discussion: The reviewed evidence suggests that BPD has its in early neurodevelopmental vulnerability and is sustained by maladaptive neurophysiological processes. Emotional dysregulation emerges as a central transdiagnostic mechanism. Self-harm may serve as a strategy for regulating emotions in response to trauma-related neural dysregulation. These findings advocate for the integration of neuroscience into psychotherapeutic practice, including the application of neuromodulation techniques and psychophysiological monitoring. Conclusions: A comprehensive understanding of BPD requires a neuropsychologically informed framework. Personalised treatment approaches combining pharmacotherapy, brain-based interventions, and developmentally adapted psychotherapies—particularly DBT, psychodynamic therapy, and trauma-informed care—are essential. Future research should prioritise interdisciplinary, longitudinal studies to further bridge the gap between neurobiological findings and clinical innovation. Full article

The dynamic control of vibrations in skyscrapers is a critical consideration in sustainable building design, particularly in response to environmental excitations such as wind impact or seismic activity. Effective vibration neutralisation plays a crucial role in providing the safety of high-rise buildings. This research introduces an innovative concept for an active vibration damper that operates based on fluid dynamic transport to adaptively alter a skyscraper’s natural frequency, thereby counteracting resonant vibrations. A distinctive feature of this system is an adjustable-length cable mechanism, allowing for the dynamic modification of the pendulum’s effective length in real time. The structure, based on cable length adjustment, enables the PTMD to precisely tune its natural frequency to variable excitation conditions, thereby improving damping during transient or resonance phenomena of the building’s dynamic behaviour. A comprehensive mathematical model based on Lagrangian mechanics outlines the governing equations for this system, capturing the interactions between pendulum motion, fluid flow, and the damping forces necessary to maintain stability. Simulation analyses examine the role of initial excitation frequency and variable damping coefficients, revealing critical insights into optimal damper performance under varied structural conditions. The findings indicate that the proposed pendulum damper effectively mitigates resonance risks, paving the way for sustainable skyscraper design through enhanced structural adaptability and resilience. This adaptive PTMD, featuring an adjustable-length cable, provides a solution for creating safe and energy-efficient skyscraper designs, aligning with sustainable architectural practices and advancing future trends in vibration management technology. The study presented in this article supports the development of modern skyscraper design, with a focus on dynamic vibration control for sustainability and structural safety. It combines advanced numerical modelling, data-driven control algorithms, and experimental validation. From a sustainability perspective, the proposed PTMD system reduces the need for oversized structural components by providing adaptive, efficient damping, thereby lowering material consumption and embedded carbon. Through dynamically retuning structural stiffness and mass, the proposed PTMD enhances resilience and energy efficiency in skyscrapers, lowers lifetime energy use associated with passive damping devices, and enhances occupant comfort. This aligns with global sustainability objectives and new-generation building standards. Full article

Mercury (Hg) pollution is a widespread ecological threat with sublethal effects on wildlife. Birds, due to their ecological diversity and sensitivity, serve as effective models for evaluating the behavioural impacts of Hg exposure. This review applies Tinbergen’s four questions: causation, ontogeny, function, and evolution, as an integrative framework. Mechanistically, Hg disrupts neuroendocrine pathways, gene expression, immune function, and hormone regulation, leading to behavioural changes such as reduced foraging, altered parental care, and impaired predator avoidance. Early-life exposure affects neural development, learning, and social behaviour into adulthood. Functionally, these changes reduce fitness by compromising reproduction and survival. Phylogenetic comparisons show interspecific variability, with piscivorous and insectivorous birds exhibiting high Hg burdens and sensitivity, linked to ecological roles and exposure. Behavioural responses often precede physiological or demographic effects, highlighting their value as early indicators. Both field and laboratory studies show that even low Hg concentrations can alter behaviour, though outcomes vary by species, life stage, and exposure route. Integrating behavioural endpoints into ecotoxicological risk assessments is essential to improve conservation strategies and understanding of sublethal pollutant effects on wildlife. Full article

Global warming is driving significant changes in aquatic ecosystems, where temperature fluctuations influence biological processes across multiple levels of organisation. As ectothermic organisms, fish are particularly susceptible, with even minor thermal shifts affecting their metabolism, behaviour, and overall fitness. Understanding these responses is essential for evaluating the ecological and evolutionary consequences of climate change. This study investigates the effects of acute (4-day) and chronic (21-day) exposure to three temperature regimes—18 °C (low), 26 °C (control), and 34 °C (high)—on the spatio-temporal shoaling behaviour of adult zebrafish (Danio rerio). Groups of four fish were tested for six minutes in water maintained at the same temperature as their prior acclimation. Shoaling behaviour was assessed by analysing shoal structure—encompassing shoal dimensions and cohesion—as well as spatial positioning. Parameters measured included inter-fish distance, shoal volume, shoal area, homogeneity index, distance to the centroid, and the shoal’s vertical and horizontal distribution. Results revealed complex behavioural changes influenced by both temperature and duration of exposure. At 18 °C, zebrafish showed a marked preference for the bottom zone and exhibited no significant temporal modulation in exploratory behaviour—patterns indicative of heightened anxiety-like responses. In contrast, exposure to 34 °C resulted in increased shoal cohesion, particularly under chronic conditions, and a progressive increase in environmental exploration over the six-minute test period. This enhancement in exploratory activity was especially evident when compared to the first minute of the test and was characterised by greater vertical movement—reflected in the increased use of the upper zone—and broader horizontal exploration, including more frequent occupation of peripheral areas. These findings align with previous research linking thermal variation to neurobiological and proteomic alterations in zebrafish. By elucidating how temperature modulates social behaviour in ectotherms, this study offers valuable insights into the potential behavioural impacts of climate change on aquatic ecosystems. Full article

Welding and cutting behaviour may affect the mechanical properties of titanium alloy welded structures, which may have some impact on the safety assessment of the structure. This study analyses changes in residual stress in Ti80 butt-welded thick plates before and after wire-cut electric discharge machining, using numerical simulations based on thermo-elastoplastic theory and the element birth and death method, validated by X-ray non-destructive testing. The transverse residual tensile stress near the weld exhibits an asymmetric bimodal distribution, while the longitudinal stress is significantly higher than the transverse stress. Wire-cut electric discharge machining had minimal influence on the transverse residual stress distribution but led to partial relief of the longitudinal residual tensile stress. The maximum reductions in transverse and longitudinal welding residual tensile stresses are approximately 60% and 36%, respectively. The findings indicate that wire-cut electric discharge machining can alter surface residual stresses in Ti alloy butt-welded thick plates. This study also establishes a numerical simulation methodology for analysing welding residual stresses and their evolution due to wire-cut electric discharge machining. The results provide a theoretical basis for analysing the structural strength and safety of Ti-alloy-based deep-sea submersibles. Full article

The forging industry has increasingly emphasised quality and reproducibility, making computer simulations essential for predicting and improving the process. A major challenge in cold upset forging is billet buckling, which leads to defective products. Existing numerical models, such as the Euler and Rankine-Gordon formulas, mainly focus on elastic buckling. This study aimed to develop a numerical model that defined inelastic buckling during forging, particularly in cold upset forging, which could be used to determine the buckled billets and their stresses, identify the deflection point for different billet geometries, and specify the optimum billet geometry for aluminium. A numerical approach was used to model the forging operation and obtain simulation data for stress variation against die strokes. Seven billet geometries (10–40 mm in diameter, each with a length of 120 mm) and three frictional conditions (µ = 0.12, 0.16, and 0.35) were applied. The simulation results showed that the billet geometry and the strain hardening exponent had a crucial impact on the buckling behaviour, while friction seemed to alter the overall billet stresses. Rigorous non-linear regression and iterations showed that the numerical model successfully estimated the buckling stresses but failed to identify the buckling points through stress differences. Full article

This study evaluated the adsorption and desorption of imidacloprid (IMI), thiamethoxam (THM) and clothianidin (CLO) in an andisol (Freire soil) and an inceptisol (Chufquén soil) from southern Chile with different organic matter and clay contents. The soils had a slightly acidic pH and clay and clay-loam textures. The tests were carried out at 20 °C with CaCl₂ 0.01 M as the electrolyte. Kinetic experiments were performed and isotherms were fitted to the pseudo-second-order, Elovich, Weber–Morris, Freundlich and Langmuir models. The kinetics were best described by the pseudo-second-order model (R² > 0.99), indicating chemisorption; the rate was the highest for THM, although IMI and CLO achieved the highest retention capacities. The Chufquén samples, with lower organic matter but 52% clay, exhibited the highest K_f and q_m of up to 12.4 and 270 mg kg⁻¹, respectively, while the K_d (2.3–6.9 L kg⁻¹) and K_oc (24–167 L kg⁻¹) coefficients revealed a moderate leaching risk. THM was the most mobile compound due to its high solubility. Desorption was partially irreversible (H = 0.48–1.48), indicating persistence in soil. FTIR analysis confirmed the interaction with O-Al-O/O-O-Si-O groups without alterations in the mineral structure. In the soils examined in this study, the clay fraction and variable-charge minerals, rather than organic matter, were more closely associated with the adsorption behaviour of these NNIs. Full article

Background/Objectives: Head and neck squamous cell carcinoma (HNSCC) ranks sixth in the world in terms of incidence. Small proline-rich proteins (SPRRs) are precursors of the keratinocyte envelope and act as substrates of transglutaminase. A change in SPRR expression is characteristic in a few types of cancer. Our aim was to determine the concentration of SPRR1A and SPRR2A in tumours samples obtained from 61 patients with HNSCC (OSCC, OPSCC, LSCC, HPSCC, NCSCC, and SSCC). Also, we aimed to determine the relationship between protein concentration and other clinical and/or demographic variables. Methods: An ELISA test was used to determine the concentrations of SPRR in the tumour tissue homogenates. Results: In margin samples, we found a statistically significant association between SPRR1A levels and nodal status (N) and between SPRR1A levels in tumours and margins with G2 histological grade. When we analysed the effect of tobacco and alcohol habits, we found a statistically significant difference between the SPRR1A and SPRR2A amount in smokers and non-smokers in margin samples. Also, we found a statistically significant difference between the SPRR1A and SPRR2A levels in tumour and margin samples obtained from patients that either abstain and occasionally or regularly consume alcohol. Furthermore, we found in tumour and margin samples from patients with concomitant diseases an association between SPRR1A and SPRR2A levels. Our results showed altered concentrations of SPRR1A at margins, depending on HPV status. Conclusions: These results suggest that differences in SPRR proteins are determined by disease status and unhealthy behaviours, which, in a wider perspective, can influence carcinogenesis. Full article

The development of mineral, biodegradable sunscreens that can offer both high photoprotection and long-term colloidal stability, while limiting synthetic additives, presents a significant challenge. A linseed oil nanoemulsion co-stabilised by ZnO nanoparticles and the eco-friendly surfactant Appyclean 6552 was formulated, and the effect of incorporating fumed silica/alumina (Aerosil COK 84) was evaluated. A central composite response surface design was used to ascertain the oil/ZnO ratio that maximised the in vitro sun protection factor at sub-300 nm droplet size. The incorporation of Aerosil at concentrations ranging from 0 to 2 wt.% resulted in a transformation of the dispersion from a nearly Newtonian state to a weak-gel behaviour. This alteration was accompanied by a reduction in the Turbiscan Stability Index. Microscopic analysis has revealed a hierarchical particle architecture, in which ZnO forms Pickering shells around each droplet, while Aerosil aggregates bridge neighboring interfaces, creating a percolated silica scaffold that immobilises droplets and amplifies multiple UV scattering. The findings demonstrate that coupling interfacial Pickering armour with a continuous silica network yields a greener, physically robust mineral sunscreen and offers a transferable strategy for stabilising plant-oil emulsions containing inorganic actives. Full article

Introduction: Chewing gum is a widespread, seemingly mundane behaviour that has been linked to diverse benefits such as improved cognitive performance, reduced stress, and enhanced alertness. While animal and human research indicate that mastication engages extensive sensorimotor networks and may also modulate higher-order cognitive and emotional processes, questions remain about the specific neural mechanisms involved. This review combines findings from neuroimaging studies—including fMRI, fNIRS, and EEG—that investigate how chewing gum alters brain activity in humans. Methods: Using a targeted search strategy, we screened the major databases (PubMed/Medline, Scopus, ResearchGate, Google Scholar, and Cochrane) from January 1980 to March 2025 for clinical studies published in English. Eligible studies explicitly measured brain activity during gum chewing using EEG, fNIRS, or fMRI. Results: After a title/abstract screening and a full-text review, thirty-two studies met the inclusion criteria for this review: 15 utilising fMRI, 10 using fNIRS, 2 using both fNIRS and EEG, and 5 employing EEG. Overall, the fMRI investigations consistently reported strong activation in bilateral motor and somatosensory cortices, the supplementary motor area, the insula, the cerebellum, and the thalamus, during gum chewing, with several studies also noting involvement of higher-order prefrontal and cingulate regions, particularly under stress conditions or when participants chewed flavoured gum. The fNIRS findings indicated that chewing gum increased oxygenated haemoglobin in the prefrontal cortex, reflecting heightened cortical blood flow; these effects were often amplified when the gum was flavoured or when participants were exposed to stressful stimuli, suggesting that both sensory and emotional variables can influence chewing-related cortical responses. Finally, the EEG studies documented transient increases in alpha and beta wave power during gum chewing, particularly when flavoured gum was used, and reported short-lived enhancements in vigilance or alertness, which tended to subside soon after participants ceased chewing. Conclusions: Neuroimaging data indicate that chewing gum reliably engages broad sensorimotor circuits while also influencing regions tied to attention, stress regulation, and possibly memory. Although these effects are often short-lived, the range of outcomes—from changes in cortical oxygenation to shifts in EEG power—underscores chewing gum’s capacity to modulate brain function beyond simple oral motor control. However, at this time, the neural changes associated with gum chewing cannot be directly linked to the positive behavioural and functional outcomes observed in studies that measure these effects without the use of neuroimaging techniques. Future research should address longer-term impacts, refine methods to isolate flavour or stress variables, and explore potential therapeutic applications for mastication-based interventions. Full article

The curing reaction of hydroxyl-terminated polybutadiene (HTPB) solid propellant slurry alters its internal molecular structure, leading to variations in rheological properties. This study investigates the evolution of the rheological behaviour of HTPB propellant slurry during the curing process. Rheological parameters of the slurry at different curing stages were measured using a rotational rheometer, and its time-dependent rheological characteristics were systematically analysed. Building upon the Herschel–Bulkley–Papanastasiou (HBP) viscosity model, a temporal variable was innovatively incorporated to extend the model into the time domain, resulting in the development of the Herschel–Bulkley–Papanastasiou–Wang (HBPW) constitutive viscosity model. Model parameters were determined through experimental data, and the accuracy of the HBPW model was rigorously validated by comparing numerical simulations with experimental results. The findings demonstrate that the HBPW model effectively captures the viscosity variation patterns of HTPB propellant slurry with respect to both shear rate and curing time, exhibiting a minimal discrepancy of 1.7525% between simulations and experimental data. This work establishes a novel theoretical framework for analysing the rheological properties of HTPB propellant slurry, providing a scientific foundation for optimised propellant formulation design and processing techniques. Full article