University of Cádiz
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Individual entrepreneurial orientation and digital entrepreneurial intention: examining the mediating role of digital competencies
No full textPurpose. This study explores the relationship between individual entrepreneurial orientation and digital entrepreneurial intention, focusing on the potential mediating role of digital competencies within the framework of Social Cognitive Theory. Individual entrepreneurial orientation—comprising risk-taking, innovativeness, and proactiveness—is examined in connection with students' digital competencies and their digital entrepreneurial intention.
Design/methodology/approach. Our sample comprised 751 Spanish university students who completed a questionnaire including questions on entrepreneurial orientation, digital competencies, and digital entrepreneurship intention. The Multiple Mediator Model methodology was used to test the proposed hypotheses.
Findings. The results obtained show that risk-taking and innovativeness significantly support digital entrepreneurial intention. Moreover, all dimensions of individual entrepreneurial orientation were positively related to the development of digital competencies, specifically information, communication, content development, and problem-solving. Importantly, the analysis confirmed the mediating effect of the digital competencies—specifically information, digital communication, and content creation—in the relationship between individual entrepreneurial orientation and digital entrepreneurial intention.
Originality. This research contributes to the understanding of digital entrepreneurial intention through the integration of individual entrepreneurial orientation and students' digital competencies, offering ideas for developing specific educational programmes that foster both individual entrepreneurial orientation and students' digital competencies
A Time-Fractional Bioheat Model with Perfusion and Spatial Source for Laser Thermal Coagulation in Hepatic Tissue
No full textThis work presents an analytical investigation of a time-fractional bioheat transfer model for laser thermal coagulation (LTC) in hepatic tissue. The model incorporates a Caputo fractional time derivative of order to account for thermal memory effects and nonlocal temporal behavior in biological tissues. A spatially decaying laser heat source and blood perfusion are included to simulate realistic in vivo and ex vivo thermal scenarios. We formulate the problem in a one-dimensional semi-infinite domain and derive closed-form solutions using Laplace transforms, involving the Mittag-Leffler and scaled Wright functions. These solutions capture the anomalous diffusion phenomena typically neglected by the classical Pennes Bioheat Equation (PBE). Comparisons with experimental data reveal that the fractional-order model significantly improves accuracy in predicting early-time temperature dynamics. In particular, for , the model closely replicates the experimental temperature profile, while the classical PBE overestimates it. This study demonstrates the potential of fractional heat transport models for more precise thermal predictions in minimally invasive therapies such as LTC
From Stability to Chaos: A Complete Classification of the Damped Klein-Gordon Dynamics
No full textWe investigate the transition between stability and chaos in the damped Klein-Gordon equation, a fundamental model for wave propagation and energy dissipation. Using semigroup methods and spectral criteria, we derive explicit thresholds that determine when the system exhibits asymptotic stability and when it displays strong chaotic dynamics, including Devaney and distributional chaos as well as topological mixing. The results yield a classification of the dynamical regimes in terms of damping, stiffness, and propagation parameters, showing that the system admits only two long-term behaviours: convergence to equilibrium or chaos. This dichotomy not only unifies and extends previous partial results but also highlights the mechanisms by which linear partial differential equations can generate complex dynamics typically associated with nonlinear systems. Potential applications arise in acoustics, wave mechanics, and signal transmission, where predicting the onset of chaos versus stability is of practical importance
Mediciones del mar en los confines del mundo: la ciencia española en la Antártida
No full textEn los confines más australes del planeta, donde convergen hielo, volcanes y océano, investigadores españoles han registrado con precisión las fluctuaciones del nivel del mar en las islas Decepción y Livingston, dos enclaves estratégicos de las islas Shetland del Sur. El océano refleja los cambios del clima global: almacena calor, recibe agua del deshielo y muestra sus efectos a través de las variaciones del nivel del mar. Más allá de los resultados, es también una historia de perseverancia y ciencia en un entorno extremo
The vision of coeducation in future andalusian primary school teachers: analysis according to the variable “sex”
No full textEl presente estudio analiza la incidencia de la variable sexo en el léxico disponible de los estudiantes del último curso del Grado en Educación Primaria en Andalucía en el ámbito de la coeducación. El objetivo del estudio es doble: (1) determinar las concepciones del futuro profesorado sobre la coeducación y (2) analizar el léxico disponible aportado según la variable sexo. La muestra se compone de 168 informantes procedentes del último curso del Grado en Educación Primaria de 8 universidades andaluzas, una por cada provincia —21 estudiantes por cada universidad—. Los resultados obtenidos muestran un caudal léxico productivo y relevante en cuanto al concepto de coeducación proveniente tanto de hombres como de mujeres y no se encuentran importantes diferencias en la influencia de dicha variable. Estos hallazgos aportan nuevos enfoques en las futuras investigaciones de este ámbito y permiten tomar decisiones para mejorar la formación inicial docente
Ohmic contacts on (111)-oriented phosphorus-doped diamond fabricated by FIB transformation and surface Ga+ implantation
No full textAmong the ultra-wide bandgap (UWBG) materials, diamond has unique properties for high power device applications and can deliver p-type and n-type doping. However, the achievement of low resistive ohmic contacts on n-type diamond limits the fabrication of bipolar devices. This study investigates the use of focused Ga+ion beam (FIB) to fabricate metal-free ohmic contacts on phosphorus-doped diamond, with a doping concentration of ∼5 × 1018 cm−3estimated by cathodoluminescence. FIB irradiation was used to locally modify the diamond surface, resulting in a conductive channel with ohmic, albeit highly resistive, behaviour. Using the circular Transfer Length Method (cTLM), a specific contact resistance of 4.3·104 Ω·cm2was obtained. This value is consistent with state-of-the-art results at similar doping levels, demonstrating that FIB is a viable and efficient technique for contact formation in diamond-based electronic devices
Copper toxicity as stressor in Chaetoceros calcitrans under different salinity levels: Growth inhibition, ROS accumulation, and alterations in fatty acid and PUA profiles
No full textThe sensitivity of marine microalgae to metal contamination, particularly copper (Cu), is well recognized in ecotoxicology, providing key insights into predicting marine pollution impacts. This study examined the combined effects of Cu toxicity and salinity on the diatom Chaetoceros calcitrans under controlled laboratory conditions. Toxicity assays were conducted using two environmentally relevant Cu concentrations (2 and 5 μg L−1) and three salinity levels (33, 36, and 39) over 96 h, with cell responses analyzed via flow cytometry. Specific growth rate (SGR), chlorophyll fluorescence, fatty acid methyl ester (FAME) composition, polyunsaturated aldehydes (PUAs), and reactive oxygen species (ROS) production were evaluated. Results showed that SGR increased from 1.7 d−1 at salinity 33 to 1.9 d−1 at 39, indicating enhanced growth at higher salinity. However, Cu exposure significantly reduced SGR, particularly under 5 μg L−1 Cu at salinity 33, where SGR dropped to 0.86 d−1. ROS levels were highest under the combined low salinity (33) and 5 μg L−1 Cu treatment, suggesting strong oxidative stress. PUA profiles shifted with Cu and salinity, with stress-related compounds such as 2 E ,4 E / Z -decadienal and 2 E ,4 E / Z ,7 Z -decatrienal increasing at low salinity. Fatty acid analysis revealed marked rises in saturated fatty acids, especially palmitic acid (C16:0) and myristic acid (C14:0), under Cu exposure. In the Cu2/39 treatment, C16:0 reached 1.34 × 104 fmol cell−1 compared to 1.36 × 103 fmol cell−1 in the control. Monounsaturated fatty acids, notably palmitoleic acid (C16:1), also increased, reaching 7. 46 × 103 fmol cell−1 versus 1.71 × 103 fmol cell−1 in the control. Conversely, polyunsaturated fatty acids, including arachidonic acid (C20:4) and eicosapentaenoic acid (C20:5 n-3), decreased significantly following Cu exposure. Overall, elevated salinity mitigated Cu-induced growth inhibition but intensified oxidative and biochemical stress, underscoring the complex, endpoint-specific responses of C. calcitrans to multiple environmental stressors
Female genital self-image and psychological distress: the serial mediating effects of existential shame and limited access to emotion regulation strategies
No full textPurpose
Concern about female genital self-image (FGSI) is increasing due to its implications for women's well-being. Previous research has linked negative FGSI to psychological distress. However, the underlying mechanisms of this association remain unclear, with shame and emotional dysregulation being potential mediators. This study aimed to test a serial mediation model in which FGSI is associated with psychological distress through shame and emotional dysregulation.
Methods
A cross-sectional design was employed, with a total of 445 women (Age: M = 40.22, SD = 10.69, range = 17–70) completing an online survey.
Results
Linear regression analysis revealed a significant association between psychological distress and both existential shame and limited access to emotion regulation strategies. FGSI and the remaining dimensions of shame and emotional dysregulation did not show a direct significant association with psychological distress. Mediation analysis confirmed that the relationship between FGSI and psychological distress was fully mediated by existential shame, limited access to emotion regulation strategies, and the serial mediation of these two variables.
Conclusion
These findings have important practical implications for the development of preventive and intervention strategies aimed at women with low FGSI, focusing on addressing feelings of maladaptive shame and enhancing effective emotion regulation strategies
Quantitative assessment of PV modules affected by Type-C cracks using electroluminescence imaging
No full textCracks in photovoltaic modules are among the defects that can lead to the highest power losses. While the qualitative analysis of such failures has been widely studied, quantitative assessments remain relatively scarce. Accurately estimating the power loss associated with these defects is therefore essential to assess module performance, guide decision-making in maintenance activities and ensure long-term photovoltaic system performance. This paper presents the application of a methodology to quantify Type-C crack severity across the cells of a sample of 100 photovoltaic modules from two different manufacturers that have been in operation for 11 years. The methodology combines automatic crack segmentation of electroluminescence images with a quantitative assessment of the power losses associated with Type-C cracks. The statistical analysis of the sample indicates that the best probability distribution fitting the power loss estimation results is the Generalized Extreme Value distribution, with a mean value of 12.77%. This suggests a slightly higher average power loss than expected according to the acceptance/rejection criteria established, reflecting that the sample exhibits slight degradation while remaining operational. Furthermore, the shape of the resulting distribution suggests that it is unlikely to observe modules exceeding the 20% of power loss. The approach used to estimate power loss highlights the importance of detecting the distribution of cracks across the photovoltaic module, as concentrated Type-C cracks in a cell can lead to significant power losses for the module. The proposed approach enables proactive maintenance by identifying severely cracked modules for replacement, improving plant performance
