Boundary conditions generated by dynamic particles in SPH methods

Smoothed Particle Hydrodynamics is a purely Lagrangian method that can be applied to a wide variety of fields. The foundation and properties of the so called dynamic boundary particles (DBPs) are described in this paper. These boundary particles share the same equations of continuity and state as the moving particles placed inside the domain, although their positions and velocities remain unaltered in time or are externally prescribed. Theoretical and numerical calculations were carried out to study the collision between a moving particle and a boundary particle. The boundaries were observed to behave in an elastic manner in absence of viscosity. They allow the fluid particles to approach till a critical distance depending on the energy of the incident particle. In addition, a dam break confined in a box was used to check the validity of the approach. The good agreement between experiments and numerical results shows the reliability of DBPs

Modeling dam break behavior over a wet bed by a SPH technique

Dam break evolution over dry and wet beds is analyzed with a smoothed particle hydrodynamics model. The model is shown to accurately fit both experimental dam break profiles and the measured velocities. In addition, the model allows one to study different propagation regimes during the dam break evolution. In particular, different dissipation mechanisms were identified: bottom friction and wave breaking. Although breaking dominates over wet beds at the beginning of the movement, bottom friction becomes the main dissipation mechanism in the long run

MOTEMO-OUTDOOR: ensuring learning and health security during the COVID-19 pandemic through outdoor and online environments in higher education

The restriction measures put in place during the COVID-19 pandemic posed notable challenges for formal teaching-learning processes because they had to be adapted to ensure health security. An active learning programme applied to three environments (indoors, outdoors, and online) was tested with 273 undergraduate university students in a within-subjects experimental study. Each student was assigned to two indoor and two outdoor seminars, with a subsample (n = 30) also participating in online seminars implemented in response to the university's lockdown protocols. The learning experience and learning conditions were evaluated through six dimensions: learning, evaluative impact, hedonic experience, technical conditions, environmental conditions, and health security. Outdoor seminars were more effective than indoor seminars in terms of the learning experience, with greater differences in hedonic experience, while the indoor seminars were rated more highly than the outdoor seminars in terms of learning conditions, with a larger difference in the environmental conditions. No differences were found between online and face-to-face environments in terms of the learning experience, even though the online environment yielded better scores in the learning conditions. Apparently, this adaptation to both outdoor and online contexts through active methodologies allows overcoming of technical, environmental, and teaching limitations and improves health security, while ensuring a good learning experience and added flexibility to teaching-learning processes

Chronic fluoxetine treatment in middle-aged rats induces changes in the expression of plasticity-related molecules and in neurogenesis

<p>Abstract</p> <p>Background</p> <p>Antidepressants promote neuronal structural plasticity in young-adult rodents, but little is known of their effects on older animals. The polysialylated form of the neural cell adhesion molecule (PSA-NCAM) may mediate these structural changes through its anti-adhesive properties. PSA-NCAM is expressed in immature neurons and in a subpopulation of mature interneurons and its expression is modulated by antidepressants in the telencephalon of young-adult rodents.</p> <p>Results</p> <p>We have analyzed the effects of 14 days of fluoxetine treatment on the density of puncta expressing PSA-NCAM and different presynaptic markers in the medial prefrontal cortex, hippocampus and amygdala of middle-aged (8 months old) rats. The density of puncta expressing PSA-NCAM increased in the dorsal cingulate cortex, as well as in different hippocampal and amygdaloid regions. In these later regions there were also increases in the density of puncta expressing glutamic acid decarboxylase 65/67 (GAD6), synaptophysin (SYN), PSA-NCAM/SYN and PSA-NCAM/GAD6, but a decrease of those expressing vesicular glutamate transporter 1 (VGluT1). Since there is controversy on the effects of antidepressants on neurogenesis during aging, we analyzed the number of proliferating cells expressing Ki67 and that of immature neurons expressing doublecortin or PSA-NCAM. No significant changes were found in the subgranular zone, but the number of proliferating cells decreased in the subventricular zone.</p> <p>Conclusions</p> <p>These results indicate that the effects of fluoxetine in middle-aged rats are different to those previously described in young-adult animals, being more restricted in the mPFC and even following an opposite direction in the amygdala or the subventricular zone.</p

Tensegrity ring for a sports arena formfinding & testing

The current prototype’s key contribution to the field of light-weight structures is that it is the first time that a pure tensegrity ring has been used in place of a compression ring. This design features a cladding structure for a sports arena, which consist of a ring-shaped outer section and a central roof structure. The ring-shaped outer section of the stadium consists of a tensegrity structure, which uses textile membranes in a place of conventional tension cables to bear the tensile forces occurring between the pressure elements. The supporting framework and spatial enclosure therefore become one an extension to the tension integrity principle. The central area of the roof is covered over by a Geiger dome, which in turn is a specific version of the tensegrity principle

Contribuciones del enfoque cualitativo de corte etnometodológico al análisis de la entrevista motivacional en Atención Primaria

Este artículo propone reflexionar acerca de las contribuciones del enfoque cualitativo de corte etnometodológico (estudia la organización de las conversaciones cotidianas) en el campo de la práctica profesional, a propósito de un análisis de la interacción usuario-profesional de salud (médico o enfermera) en la situación de la entrevista motivacional en la consulta de atención primaria. El proyecto ISTAPS es un ensayo clínico multicéntrico aleatorizado por clústers realizado durante los años 2006-2008 en 11 comunidades autónomas de España que evalúan las intervenciones para ayudar a dejar de fumar, entre ellas la entrevista motivacional (EM). Desde este marco se planteó un subestudio cualitativo con el objetivo de conocer como se realizaban las acciones en un contexto interaccional, negociable y cambiante como el que se daba en la consulta de la AP. Se realizaron videograbaciones de la EM en la consulta, que fueron la base documental para el análisis conversacional de la interacción usuario-profesional de salud (enfermera o médico) en la situación de EM. Se presentan diferentes ejemplos con la intención de ilustrar las contribuciones del enfoque cualitativo de corte etnometodológico en la práctica profesional. El primer ejemplo analiza el contexto de la consulta de atención primaria como un espacio para hablar sobre la conducta de fumar. El segundo, pone el énfasis en las estrategias que utiliza el profesional para producir una conversación centrada en la persona. El tercero, reflexiona sobre las consecuencias de la falta de acuerdo entre el usuario y el profesional acerca del tema a tratar. Finalmente, el cuarto ejemplo ilustra una relación asimétrica