176 research outputs found
Multi-bubble nodal solutions for slightly subcritical elliptic problems in domains with symmetries
We study the existence of sign-changing solutions with multiple bubbles to
the slightly subcritical problem -\Delta u=|u|^{2^*-2-\e}u \hbox{in}\Omega,
\quad u=0 \hbox{on}\partial \Omega, where is a smooth bounded domain
in , , and \e>0 is a small parameter. In
particular we prove that if is convex and satisfies a certain
symmetry, then a nodal four-bubble solution exists with two positive and two
negative bubbles
Proposal a empirical model for absorbent acoustical materials
Los materiales absorbentes acústicos son cada vez más importantes en diferentes ámbitos: acústica en la construcción, automoción, aire acondicionado, etc. Existen diferentes modelos para predecir el comportamiento acústico de materiales. Algunos de estos se basan en el ajuste de datos experimentales a una serie de
fórmulas empíricas que permiten la predicción en un rango razonable. Además, la norma UNE-EN 12354-6 permite la predicción de la absorción sonora de cualquier material absorbente fibroso con las fórmulas
propuestas por Delany & Bazley. En este trabajo se realiza una revisión de los diferentes modelos para predecir el comportamiento de materiales absorbentes acústicos y se realiza un nuevo ajuste buscando un nuevo modelo que se adapte mejor a todo tipo de materiales absorbentes.Peer Reviewe
Entornos virtuales de aprendizaje y su contribución al desarrollo de competencias en el marco de la Convergencia Europea
Las propuestas para alcanzar la Convergencia Europea exigen un giro radical que afecta al paradigma de enseñanza-aprendizaje, que supone la adopción de una nueva metodología centrada en el discente, que conlleva un cambio en los roles desempeñados por los agentes implicados en este proceso; así los docentes pierden su papel de difusores del conocimiento y transmisores de información, pasando a convertirse en facilitadores del aprendizaje, diseñadores de situaciones mediadas, generadores de habilidades de asesoramiento, propiciadores de transferencia de aprendizajes, etc. Por su parte los estudiantes, deben desarrollar nuevas competencias que impliquen una actitud más activa y comprometida con su propio aprendizaje, en permanente adaptación a los cambios sociales, alentando su crecimiento intelectual y expansión de habilidades. Los nuevos escenarios para la formación abocan a una transformación de la metodología presencial, tornándose en una metodología híbrida, que aproveche las potencialidades que la virtualidad ofrece, y que apueste por la integración de las TIC en un intento de contribuir a la optimización del proceso de enseñanza-aprendizaje. Lo cual plantea unos desafíos técnicos y pedagógicos. No se trata sólo de adquirir destrezas de uso de herramientas, sino de analizar sus implicaciones en la creación de entornos cooperativos de aprendizaje, y ponerlas al servicio de la organización y gestión del proceso formativo, sobre todo a través de la red. En este sentido, consideramos que las experiencias de enseñanza virtual de: “Educación en el ámbito rural"; “Gráficos por Computador"; “Análisis de datos con SPSS"; y “Cuestiones éticas de Ciencia y Tecnología", asignaturas que forman parte de la oferta formativa que la Universidad de Oviedo aporta al Campus Virtual Compartido del G9 (formado por las Universidades de Cantabria, La Rioja, País Vasco, Pública de Navarra, Islas Baleares, Castilla-La Mancha, Extremadura, Oviedo y Zaragoza), suponen una contribución innovadora para el desarrollo de competencias instrumentales, interpersonales y sistémicas.The proposals to reach the European convergence require of a radical change affecting the teaching‐learning paradigm and involving the adoption of a new methodology focused on teachers and a change in the roles of the agents involved. Teachers lose their role as disseminators of knowledge and information to become facilitators of learning , designers of situations, generators of assessment skills and propitiators of learning transferences. As a consequence, students must develop new competences, more active and committed attitudes towards their own learning, must constantly adapt to social changes and must encourage their own intellectual development. This new formative scenery forces the transformation of presential methodology into a hybrid methodology, which profits from the posibilities of virtuality and favours the contribution of new technologies to the improvement of the teaching‐learning process, thus, raising new technical and pedagogical challenges. Apart from the skills to use them, it’s important to analyse the implications in the creation of new cooperative learning environments and the availability to organize and manage cooperative processes by means of the net. “Rural Field Education”, “Computer Graphics”, “SPSS Data Analysis” and “Ethics in Science and Technology” are virtual subjects offered by the University of Oviedo at The G9 Shared Virtual Campus, set up by the public universities of Cantabria, La Rioja, The Basque Country, Navarra, Balearic Islands, Castille‐La Mancha, Extremadura, Oviedo and Saragossa: an innovative contribution towards the development of instrumental, personal and systemic competences
A structural model of the relationships between optimism and perceived emotional intelligence on bullying victimization and health.
Bullying is a relationship in which an individual, or a group of individuals, intentionally and repeatedly perpetrates aggressive behaviors towards someone unable to defend himself/herself. Traditional forms of bullying consist of physical, verbal and covert forms of aggressive behaviors. Recently, the new phenomenon of cyberbullying has emerged. This relatively new form of bullying is defined as a behavior displayed through electronic or digital media. Multiple variables have been related to bullying victimization including perceived emotional intelligence (PEI) and optimism. Both variables have implications on the manner in which people cope with stressful experiences as could be bullying, which in turn could affect the level of perceived health. However, there are no studies that have considered all these variables simultaneously. Therefore, the aim of the current study was to examine, via structural equation modelling, the independent contribution of EI and optimism on bullying victimization and perceived physical health in adolescents. A total of 650 secondary school students (317 boys and 333 girls, with ages ranged from 11 to 18) participated in the study. The participants completed measures of PIE (TMMS-24; Fernández-Berrocal et al., 2004), optimism (General Mood Subscale of the Emotional Quotient Inventory-Youth Version; Bar-On and Parker, 2000), bullying (School Victimization Scale; Cava et al., 2010), cyberbullying (Cyber-Victimization Scale; Buelga et al., 2012), and physical health (KIDSCREEN-10 Index; Raven-Sieberer et al., 2004). Results gave partial empirical support to the hypothesized model, and shows significant relationships between the variables: optimism on clarity and repair dimensions of IE (but not on the attention subscale), optimism and attention (but not clarity and repair dimensions) on bullying, and bullying on health. Together these findings shed light on those factors that should be considered when developing prophylactic strategies within adolescents to become more resilient to the adverse effects of bullying behavior.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Influence of post-synthetic modifications on the composition, acidity and textural properties of ZSM-22 zeolite
[EN] In this work, an extensive investigation of the preparation of a large body of desilicated ZSM-22 zeolites and their basic characterization is presented. We investigate the effects of the properties of the starting zeolite, and we employ mixtures of NaOH with CTAB or TBAOH as well as subsequent acid washings to create mesoporous zeolites. Scanning and transmission electron microscopy and nitrogen adsorption revealed that the cristal morphology of the starting zeolite appears to be the dominant parameter which influences the mesopore generation. Mesopores were effectively created within the rod-like commercial crystallites, whereas the thinner dimensions of the needle-shaped particles of the lab-made zeolite represent an obstacle for an intra-mesopore creation. The alkaline, surfactant-assisted or combined NaOH/TBAOH desilication methods resulted in mesopores with different shape and size from the commercial zeolite. The sequential acid washing generally resulted in increased micropore volume with respect to the desilicated samples. Elemental analysis showed that extra-framework Al species were generated upon the desilication treatments, which are eventually removed by the acid treatment. The acidity studied by FTIR demonstrated that this occurs without a marked modification of the Brønsted acidity, whereas the concentration of surface silanol hydroxyl groups is increased. The comparison between the total Al concentration and the amount of Al in acidic sites quantified by pyridine adsorption shows that the acidity was recovered after the acid washing and suggests that original non-acidic Al species in the starting materials may have a role in the formation of both Lewis and extra-framework species upon desilication.This publication is a part of the inGAP Centre of research-based Innovation, which receives financial support from the Norwegian Research Council under contract no. 174893.
F.R and M.T.N thank to MINECO for financial support through projects MAT2015-71842-P and SEV-2012-0267. All the authors thank the Electron Microscopy Service of the Universitat Politecnica de Valencia.Del Campo Huertas, P.; Beato, P.; Rey Garcia, F.; Navarro, MT.; Olsbye, U.; Lillerud, K.; Svelle, S. (2018). Influence of post-synthetic modifications on the composition, acidity and textural properties of ZSM-22 zeolite. Catalysis Today. 299:120-134. https://doi.org/10.1016/j.cattod.2017.04.042S12013429
Direct Synthesis of Nano-Ferrierite along the 10-Ring-Channel Direction Boosts Their Catalytic Behavior
[EN] Ferrierite zeolites with nanosized crystals and external surface areas higher than 250m(2)g(-1) have been prepared at relatively low synthesis temperature (120 degrees C) by means of the collaborative effect of two organic structure directing agents (OSDA). In this way, hierarchical porosity is achieved without the use of post-synthesis treatments that usually involve leaching of Tatoms and solid loss. Adjusting the synthesis conditions it is possible to decrease the crystallite size in the directions of the 8- and 10-ring channels, [010] and [001] respectively, reducing their average pore length to 10-30nm and increasing the number of pores accessible. The small crystal size of the nano-ferrierites results in an improved accessibility of reactants to the catalytic active centers and enhanced product diffusion, leading to higher conversion and selectivity with lower deactivation rates for the oligomerization of 1-pentene into longer-chain olefins.This work has been supported by the European Union through the European Research Council (ERC-AdG-2014-671093, SynCatMatch) the Spanish government through the "Severo Ochoa Program" (SEV-2016-0683) and CTQ2015-70126-R, and by the Fundacion Ramon Areces through a research project within the "Life and Materials Sciences" program. M.R.D.-R. acknowledges "La Caixa-Severo Ochoa" International PhD Fellowships (call 2015). The Electron Microscopy Service of the Universitat Politecnica de Valencia is acknowledged for its help in sample characterization. We thank Dr. Manuel Moliner for helpful discussions.Margarit Benavent, VJ.; Díaz-Rey, MDR.; Navarro Villalba, MT.; Martínez, C.; Corma Canós, A. (2018). Direct Synthesis of Nano-Ferrierite along the 10-Ring-Channel Direction Boosts Their Catalytic Behavior. Angewandte Chemie International Edition. 57(13):3459-3463. https://doi.org/10.1002/anie.201711418S34593463571
A Mathematical Study of Barcelona Metro Network
The knowledge of the topological structure and the automatic fare collection systems in urban public transport produce many data that need to be adequately analyzed, processed and presented. These data provide a powerful tool to improve the quality of transport services and plan ahead. This paper aims at studying, from a mathematical and statistical point of view, the Barcelona metro network; specifically: (1) the structural and robustness characteristics of the transportation network are computed and analyzed considering the complex network analysis; and (2) the common characteristics of the different subway stations of Barcelona, based on the passenger hourly entries, are identified through hierarchical clustering analysis. These results will be of great help in planning and restructuring transport to cope with the new social conditions, after the pandemic.This research was funded by Ministerio de Ciencia, Innovación y Universidades (MCIU, Spain), Agencia Estatal de Investigación (AEI, Spain), and Fondo Europeo de Desarrollo Regional (FEDER, UE) under project NOTREDAMME and by Scientific Research Grant of the “Fundación Memoria D. Samuel Solórzano Barruso”, University of Salamanca
Efectividad de un programa de intervención contra el ciberbullying
Antecedentes
. La inmersión de las TICs e internet en la vida de los jóvenes y los riesgos
que de su uso se derivan ponen de manifiesto la necesidad de alfabetizar digitalmente a
los adolescentes. El programa ConRed, dirigido a docentes, alumnos y familias, ha
conseguido que entre estudiantes se reduzcan problemas como el ciberbullying, la
dependencia virtual y el escaso control sobre la información personal publicada en
Internet. Este artículo examina el impacto de una adaptación del Proyecto ConRed tras
eliminar su ca
rácter ecológico y reducir el número de sesiones con el alumnado.
Método
. Se ha utilizado una metodología cuasi experimental y una muestra de 355
estudiantes entre grupo experimental (N=163) y control (N=192) (51,7%♀; Edad M=
14,6; DT= 1,7), quienes cumpli
mentaron en pretest y postest cuestionarios sobre
ciberbullying, percepción del control de la información y dependencia a internet.
Resultados
. Los análisis de ANOVA de medidas repetidas solo reflejaron resultados
favorables para la prevención e intervención de bulling.
Conclusiones. Este trabajo
constata la necesidad de intervenciones anti-ciberbullying donde participe alumnado,
familias y profesorado y refuerza la evidencia científica de que los programas
destinados en reducir la violencia en la red influyen irremediablemente en los agresores
de violencia tradicional.Background
. ICT Immersion and the internet in the youngs lives and
the risks arising
from its use highlight the need for digital literacy to adolescents. The ConRed program,
aimed at teachers, students and families, has made problems like cyberbullying, the
virtual dependency and poor control over personal information on
the Internet among
students to be reduced. This article examines the impact of an ConRed proyect
adaptation after removing their ecological character and reduce the number of sessions with the students.
Method
. We used a quasi-experimental methodology and
a sample of
355 students in the experimental group (N = 163) and control (N = 192) (51.7% ♀, age
M = 14.6, SD = 1.7) who completed pretest and posttest questionnaires about
cyberbullying, control of information perception and internet dependency. Results.
Analysis of repeated ANOVA measures only reflected favorable for the prevention and
intervention of traditional bullying results.
Conclusions
. This work shows the necessity
of anti-cyberbullying interventions where students, families and teachers participates
and reinforces the scientific evidence that programs aimed at reducing violence in the
network inevitably affect traditional violence offenders
Promoter Methylation of RASSF1A Associates to Adult Secondary Glioblastomas and Pediatric Glioblastomas
While allelic losses and mutations of tumor suppressor genes implicated in the etiology of astrocytoma have been widely assessed, the role of epigenetics is still a matter of study. We analyzed the frequency of promoter hypermethylation by methylation-specific PCR (MSP) in five tumor suppressor genes (PTEN, MGMT, RASSF1A, p14ARF, and p16INK4A), in astrocytoma samples and cell lines. RASSF1A was the most frequently hypermethylated gene in all grades of astrocytoma samples, in cell lines, and in adult secondary GBM. It was followed by MGMT. PTEN showed a slight methylation signal in only one GBM and one pilocytic astrocytoma, and in two cell lines; while p14ARF and p16INK4A did not show any evidence of methylation in primary tumors or cell lines. In pediatric GBM, RASSF1A was again the most frequently altered gene, followed by MGMT; PTEN, p14 and p16 showed no alterations. Lack or reduced expression of RASSF1A in cell lines was correlated with the presence of methylation. RASSF1A promoter hypermethylation might be used as a diagnostic marker for secondary GBM and pediatric GBM. Promoter hypermethylation might not be an important inactivation mechanism in other genes like PTEN, p14ARF and p16INK4A, in which other alterations (mutations, homozygous deletions) are prevalent
Management of Open Fracture
Open fractures are common and their prevalence is increasing in elderly people. The burden of open fractures is high because of economic and social costs. Most open fractures occur in lower limbs. The use of validated protocols, will optimize our outcomes when treating open fractures. The first step began with the proper identification of the fracture characteristics and the hidden soft tissue injury. The use of an adequate and early antibiotic prophylaxis is mandatory and then, we have to perform adequate irrigation and debridement. Finally, we have to decide to temporally fix the fracture or proceed with the definitive fixation method. Recently, the creation of dedicated “orthoplastic” units has increased the outcomes in high-energy tibial fractures. These fractures should be managed in adequate trauma centers that should be used to face all the complications that will appear during the reconstruction procedure because complications can be as high as 50% in high-energy open fractures
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