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Distinct evaporation and combustion behaviors of suspended and unsuspended nanodiesel droplets
No full textThis work reports the main evaporation and combustion characteristics of diesel droplets doped with different concentrations of alumina and ceria nanoparticles (NPs) for a range of conditions scarcely explored and relevant for combustion applications: high-temperature and reducing/oxidizing atmospheres (0/10 % O2). Due to the potential influence of the particular experimental conditions, all tests are performed using two different setups: a free-falling droplet (FFD) rig and a suspended droplet (SD) facility, following a systematic study that is considered especially pertinent for particle-laden fuels. The reported results demonstrate, for the first time, a great influence of the test method on some of the observed behaviors, which can perfectly justify some contradictions and even inconsistencies observed in previous works. Tests on unsuspended nanodiesel droplets provide smooth evaporation curves until the onset of a single and violent microexplosion that shatters the droplets, whereas the testing of suspended droplets yields a fluctuating evaporation process, with a wide range of sequential disruptive phenomena of different intensities (swelling, puffing, weak microexplosions). These clear differences point to the impact of the suspension filaments on disruptive behaviors for the range of conditions explored, even when very thin ceramic fibers are employed. In spite of these differences, some common features have also been identified. Namely, the addition of NPs does not drive significant changes in the droplet evaporation rate, probably due to the small impact of thermal radiation for the tested conditions. However, the onset of disruptive phenomena shortens the liquid conversion times as compared to neat diesel, with an earlier occurrence as the NP concentration increases, especially for FFD tests. Among the two tested nanoparticles, ceria shows significantly stronger disruptive events and also a progressive reduction in evaporation rate for unsuspended droplets, which is consistent with the formation of a less permeable shell for this kind of NP
Automated broken object-level authorization attack detection in REST APIs through OpenAPI to colored petri nets transformation
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The representational state transfer architectural style (REST) specifies a set of rules for creating web services. In REST, data and functionality are considered resources, accessed, and manipulated using a uniform, well-defined set of rules. RESTful web services are web services that follow the REST architectural style and are exposed to the Internet using RESTful APIs. Most of them are described by OpenAPI, a standard language-independent interface for RESTful APIs. RESTful APIs are continuously available on the Internet and are therefore a common target for cyberattacks. To prevent vulnerabilities and reduce risks in web systems, there are several security guidelines available, such as those provided by the Open Web Application Security Project (OWASP) foundation. A common vulnerability in web services is broken object level authorization (BOLA), which allows an attacker to modify or delete data or perform actions intended only for authorized users. For example, an attacker can change an order status, delete a user account, or add unauthorized data to the server. In this paper, we propose a transformation from OpenAPI to Petri nets, which enables formal modeling and analysis of REST APIs using existing Petri net analysis techniques to detect potential security risks directly from the analysis of web server logs. In addition, we also provide a tool, named , which automatically performs model transformation (taking the OpenAPI specification as input) and BOLA attack detection by analyzing web server execution traces. We apply it to a case study of a vulnerable web application to demonstrate its applicability. Our results show that it is capable of detecting BOLA attacks with an accuracy greater than 95% in the proposed scenarios
Deciphering the Impact of Current, Composition, and Potential on the Lithiation Behavior of Si-Rich Silicon-Graphite Anodes
Get PDFAdding silicon (Si) to graphite (Gr) anodes is an effective approach for boosting the energy density of lithium‐ion batteries, but it also triggers mechanical instability due to Si volume changes upon (de)lithiation reactions. In this work, component‐specific (de)lithiation dynamics on Si‐rich (30 and 70 wt.% Si) SiGr anodes at various charge/discharge C‐rates are unveiled and compared to a graphite‐only electrode (100Gr) via operando synchrotron X‐ray diffraction coupled with differential capacity plots analysis. Results show preferential lithiation of amorphous Si above ≈200 mV and competing lithiation of Gr, amorphous Si, and crystalline Si below ≈200 mV. Discharge proceeds via sequential delithiation of Gr and amorphous lithium silicide. Si shifts the interconversion potentials of graphite intercalation compounds, lowering the Gr state of charge compared to 100Gr. In the 30% Si electrode, crystalline Si amorphization at potentials <110 mV is found to be kinetically hindered at C‐rates higher than C/5, which can be key for enhancing the cycling stability of SiGr anodes. The 70% Si electrode exhibits restricted lithium diffusion in Gr, full Si amorphization, and Li15Si4 formation. These findings related to the potential‐ and current‐dependent dynamic changes on SiGr blends are crucial for designing stable high energy density SiGr anodes
¿Replicar a los maestros? Inteligencia artificial y diálogos actuales con la tradición pictórica española
Get PDFEl estudio y la réplica del estilo de los artistas del pasado ha sido, a lo largo de la historia del arte, una constante en la educación artística. La copia ha tenido un papel sustancial en la formación de artistas como demuestran, en el caso español, las visitas de copistas al Museo del Prado. En los últimos años, la irrupción de la inteligencia artificial (IA) en la praxis artística ha dado lugar a experiencias en las que, con la asistencia de estas nuevas tecnologías, puede recrearse el proceso de aprendizaje humano y generar obras de arte que imitan el estilo de los artistas del pasado. A pesar del considerable eco mediático que han recibido estas experiencias, la historia del arte, en el contexto español, todavía no les ha prestado atención. A través del presente artículo ofrecemos, desde el campo de estudio de la cultura visual, ciertas claves para el análisis histórico-artístico de estas nuevas obras de arte que han suscitado controvertidos debates sobre las nociones de autoría, autenticidad y originalidad. Para ello, realizamos un estudio comparado de tres proyectos de recuperación del arte de los maestros con asistencia de la IA: la recreación del lienzo perdido de Velázquez: La expulsión de los moriscos (1627), con una finalidad histórico-artística; la génesis mediante IA de dibujos que siguen el estilo de Goya, con un objetivo educativo; y la recuperación, con fines comerciales, de una pintura de Santiago Rusiñol: Vista del Parc del Laberint d’Horta, subyacente a un óleo de Pablo Picasso.
Enhancing electrical properties in CaMnO<sub>3</sub>-based ceramics: The impact of single doping with different elements
No full textThis study explores the effect of single doping with different rare earth elements (Y, La, and Yb) on the structural, morphological and electrical properties of CaMnO3 bulk ceramics, aiming to improve their thermoelectric performance. Ca(1‐x)RxMnO3 (R = Y, La, Yb; x = 0, 0.05, 0.10) samples were synthesized via a solid‐state reaction. XRD analysis confirmed the thermoelectric CaMnO3 phase as the major one, with orthorhombic perovskite structure. Small amounts of secondary phases (CaMn2O4 and Mn2O3) were also detected in some doped samples. The addition of dopants influenced the unit cell parameters, producing a shift to lower 2θ angles, confirming their incorporation into the ceramic structure. SEM micrographs revealed a significant reduction in grain size upon doping. Electrical resistivity measurements showed a metallic behavior for all doped samples. The Y‐doped samples exhibited the highest resistivity values while the Yb‐doped samples showed the lowest values (6.8 mΩ cm for the 0.10 doped one), which are among the lowest found in literature for this compound. The Seebeck coefficient values show minor changes for 0.05 doped samples when they decreased with increasing concentration of dopant. Consequently, the highest values were observed for 0.05‐doped sample (−215 µV/K), independently of the dopant. This value is much higher than the ones typically reported in the literature. The highest value of the power factor was calculated for the 0.05 Yb doped sample, reaching approximately 0.56 mW/K2·m at 800°C. This value is higher than the best presented in the literature for this compound, to the best of our knowledge, and suggests that Yb3+ doping greatly enhances the high‐temperature thermoelectric performance of bulk CaMnO3 ceramics, making it a promising dopant for high‐efficiency thermoelectric materials
Avatares y estereotipos. Sesgos algorítmicos de la sonrisa femenina generada por inteligencia artificial
Get PDFLa inteligencia artificial copa nuestra actualidad. Como intriga, ante su novedad; como desarrollo tecnológico y como creación. Ante este escenario, desde la perspectiva de género y del campo de estudio de la cultura visual, se analiza cómo se representa la risa femenina en las imágenes de IA generativa. Un objetivo investigador cuya hipótesis de partida busca comprobar si se perpetúan estereotipos de la pintura clásica, los sesgos de género y cuestiones como la locura o la excentricidad en las representaciones contemporáneas. Para ello, como metodología, se efectúa un análisis de contenido con categorías sobre imagen, feminidad y risa sobre una treintena de imágenes seleccionadas de forma objetiva. Con ellas, también se consigue debatir sobre el proceso de creación artificial del banco de imágenes Shutterstock que se acoge a la ética del creador y permite avisar de imágenes dañinas. Sobre esta muestra, se visualiza un trazo sexualizado de la sonrisa femenina, al simbolizarse a través de mujeres modélicas, con escotes prominentes, vestidas con cuero o tacones. Unas representaciones que se muestran superiores al género masculino, sobre el que ríen. Por otra parte, se constata poca racialidad y representatividad de edad. Son pocos los avatares que muestran una risa salutífera y divertida, sobre un continuismo de excentricidad y estereotipos de control y deseo, lo que perpetua viejas brechas de género y conduce a esquemas sin variación sobre una risa bella y libre
Effectiveness of an online self-guided intervention (MINDxYOU) for reducing stress and promoting mental health among health professionals: results from a stepped wedge cluster-randomized trial (Preprint)
Get PDFBackground: The high levels of sustained stress that health professionals often experience are a significant risk factor for developing mental health problems, such as anxiety, depression, and somatic symptoms, that not only affect their well-being but also have major social and organizational consequences. Different interventions, including those based on third-wave psychotherapy principles (ie, mindfulness, compassion, and acceptance), have proven to be effective in reducing stress in this population. Among them, those delivered on the web constitute a promising alternative with notable advantages in accessibility and flexibility, but some adherence inconveniences may limit their efficacy.
Objective: This study aimed to evaluate the effectiveness of the MINDxYOU program, a web-based self-guided intervention based on third-wave psychotherapy principles, to reduce perceived stress and promote mental health in a sample of health professionals.
Methods: In a stepped-wedge cluster randomized design, 357 health professionals from health centers in Aragon and Málaga, Spain, were recruited. They were divided into 6 clusters—3 per region—and randomly assigned to 1 of the 3 sequences, each starting with a control phase and then transitioning to the intervention phase (the MINDxYOU program) after 8, 16, or 24 weeks. This self-guided, web-based program, designed to be completed over 8 weeks, included weekly contact (via WhatsApp, call, or email) from the research team to promote adherence. Participants were assessed on the web every 8 weeks for 5 assessments.
Perceived stress was the study’s primary outcome, with additional measures of clinical factors (anxiety, depression, and somatization) and process variables (resilience, mindfulness, compassion, and acceptance).
Results: The program was initiated by 229 participants, 112 (48.9%) of whom were completers (ie, completed at least 3 of the 4 modules). Perceived stress demonstrated a significant reduction both when considering the entire sample (β=–1.08, SE 0.51; P=.03) and the sample of completers (β=–1.84, SE 0.62; P=.003). The proportion of participants reflecting “low stress” increased after the treatment (n=90, 46.6% vs n=100, 28.8% at baseline). Intracluster analysis revealed that pre- versus postintervention
moderate effects were present in 2 clusters (Cohen d=0.46 and 0.62), and these were maintained in subsequent assessments. The linear mixed-effects models also showed that depression, anxiety, and somatization, as well as resilience, self-compassion, and some mindfulness facets, experienced significant improvements (P<.05) when comparing the intervention and control phases.
Conclusions: The MINDxYOU program was effective in reducing perceived stress and promoting mental health, as well as increasing resilience, mindfulness facets, and self-compassion. These effects suggest that participants experienced a tangible improvement that could potentially enhance their well-being. Adherence to the intervention was moderate, while program use was notable compared to similar interventions. Finding ways to promote adherence to the intervention would contribute to increasing the effectiveness of this progra
How to improve sustainability of nutrient dense diets for children and adolescents: an exemplary assessment in Germany
No full textBackground: The global climate crisis requires a paradigm shift in dietary concepts, respecting the needs of children. A global reference diet has been suggested by the EAT-Lancet Commission. On this basis, the detailed “Planetary Health Diet Index” (PHDI) has been proposed. The objective of this assessment is (1) to apply the PHDI to the Food-Based Dietary Guidelines, the so-called Optimized Mixed Diet (OMD) for children and adolescents in Germany in its original composition and (2) to check how the planetary value of the OMD could be improved by modifying food selection within meals while keeping the high nutrient densities of the guideline diet.
Methods: The PHDI specifies 16 food groups and their proportion of total daily energy intake. The PHDI of the original OMD was calculated by assigning the foods of the 7-day menu to the PHDI food groups in order to score them. In this way, it became apparent which food groups had the potential to improve the sustainability. The diet was then updated by either reducing or increasing individual foods from these food groups in the meals and deriving the resulting PHDI. The nutrient densities of the original and updated daily OMD were calculated.
Results: The original diet obtained a PHDI score of 68.24 points, representing 45.5% of the theoretical maximum of 150 points. The following food groups achieved 9.9 to 10 out of 10 points: fruits, total vegetables, fish & seafood, vegetable oils, chicken (and substitutes). Conversely, food groups receiving a zero score included tubers & potatoes, dairy, red meat, animal fat, and added sugars. The updated diet resulted in increased consumption of ‘nuts & peanuts’, ‘legumes’, ‘green vegetables’, ‘whole grains’, and decreased consumption of ‘tubers & potatoes’ and ‘red meat’. Overall, the PHDI increased from 68.24 to 81.51 points with the updated OMD, reflecting a 13.27% increase compared to the original diet. The nutrient densities were not significantly affected, but even slightly increased for most nutrients.
Conclusions: The PHDI was applied to demonstrate how the sustainability of the guideline diet for children and adolescents in Germany could be improved through changes in individual food groups that can be easily implemented in practice while maintaining high nutrient densities and acceptability for children
High Relative Accuracy With Collocation Matrices of q-Jacobi Polynomials
Get PDFLittle ‐Jacobi polynomials belong to the field of quantum calculus. This article obtains the bidiagonal decomposition of the collocation matrices of these polynomials, showing that, in many cases, it can be constructed to high relative accuracy (HRA). Then, it can be used to compute with HRA the inverses, eigenvalues, and singular values of these matrices. Numerical experiments are provided and illustrate the excellent results obtained when applying the presented methods
Comparative Analysis of 2 Commercially Available Assays for Therapeutic Drug Monitoring of Infliximab and Adalimumab
No full textBackground: Tumor necrosis factor is a crucial proinflammatory cytokine in immune-mediated diseases. Tumor necrosis factor inhibitors (TNFi), such as infliximab and adalimumab, effectively treat rheumatological and digestive disorders. However, challenges such as primary nonresponse, secondary treatment failure, or adverse reactions limit their efficacy. Monitoring TNFi levels is essential for optimizing treatment and improving outcomes. An enzyme-linked immunosorbent assay (ELISA; Promonitor) was compared with 2 commercially available methods for quantifying infliximab and adalimumab levels: the chemiluminescence assay (i-Track10) and fluorescence assay (Afias-10).
Methods: Serum samples from 166 patients with inflammatory bowel disease were analyzed. Drug levels were measured using i-Track10, Afias-10, and Promonitor. Spearman's correlation analysis, Bland–Altman analysis, analysis of differences, Passing–Bablok regression, and Cohen kappa for agreement assessment were used for statistical analysis.
Results: Strong correlations were observed between Promonitor and Afias-10 for infliximab (rs = 0.982) and adalimumab (rs = 0.972), and with i-Track10 (rs = 0.935 for infliximab, rs = 0.947 for adalimumab). However, significant differences indicated noninterchangeability with ELISA. Passing–Bablok regression showed systematic and proportional biases. Cohen kappa exhibited higher concordance with Afias-10 for therapeutic ranges (κ = 0.962 for infliximab, κ = 0.849 for adalimumab) compared with i-Track10.
Conclusions: Afias-10 and i-Track10 are suitable for TNFi monitoring but are not interchangeable with ELISA. Consistent assay methods should be used for patient monitoring to ensure accuracy and reliability