In Vitro Surfactant and Perfluorocarbon Aerosol Deposition in a Neonatal Physical Model of the Upper Conducting Airways

Objective: Aerosol delivery holds potential to release surfactant or perfluorocarbon (PFC) to the lungs of neonates with respiratory distress syndrome with minimal airway manipulation. Nevertheless, lung deposition in neonates tends to be very low due to extremely low lung volumes, narrow airways and high respiratory rates. In the present study, the feasibility of enhancing lung deposition by intracorporeal delivery of aerosols was investigated using a physical model of neonatal conducting airways. Methods: The main characteristics of the surfactant and PFC aerosols produced by a nebulization system, including the distal air pressure and air flow rate, liquid flow rate and mass median aerodynamic diameter (MMAD), were measured at different driving pressures (4-7 bar). Then, a three-dimensional model of the upper conducting airways of a neonate was manufactured by rapid prototyping and a deposition study was conducted. Results: The nebulization system produced relatively large amounts of aerosol ranging between 0.3 +/- 0.0 ml/min for surfactant at a driving pressure of 4 bar, and 2.0 +/- 0.1 ml/min for distilled water (H(2)Od) at 6 bar, with MMADs between 2.61 +/- 0.1 mu m for PFD at 7 bar and 10.18 +/- 0.4 mu m for FC-75 at 6 bar. The deposition study showed that for surfactant and H(2)Od aerosols, the highest percentage of the aerosolized mass (similar to 65%) was collected beyond the third generation of branching in the airway model. The use of this delivery system in combination with continuous positive airway pressure set at 5 cmH(2)O only increased total airway pressure by 1.59 cmH(2)O at the highest driving pressure (7 bar). Conclusion: This aerosol generating system has the potential to deliver relatively large amounts of surfactant and PFC beyond the third generation of branching in a neonatal airway model with minimal alteration of pre-set respiratory support.

[G_Hondarribia_Muralla] Documentación geométrica de las murallas de Hondarribia

[ES] Al respecto del modelo virtual con texturas fotográficas generado en este proyecto, se puede consultar también el siguiente artículo:

An Alternative View of the US Price-Dividend Ratio Dynamics

As a necessary condition for the validity of the present value model, the price-dividend ratio must be stationary. However, significant market episodes seem to provide evidence of prices significantly drifting apart from dividends while other episodes show prices anchoring back to dividends. This paper investigates the stationarity of this ratio in the context of a Markov- switching model à la Hamilton (1989) where an asymmetric speed of adjustment towards a unique attractor is introduced. A three-regime model displays the best regime identification and reveals that the first part of the 90’s boom (1985-1995) and the post-war period are characterized by a stationary state featuring a slow reverting process to a relatively high attractor. Interestingly, the latter part of the 90’s boom (1996-2000), characterized by a growing price-dividend ratio, is entirely attributed to a stationary regime featuring a highly reverting process to the attractor. Finally, the post-Lehman Brothers episode of the subprime crisis can be classified into a temporary nonstationary regime.

[Z_Sadaba_Mausoleo] Documentación geométrica del mausoleo romano de «La Sinagoga» (Sádaba, Zaragoza)

[ES] Se conoce como la «Sinagoga» de Sádaba a las ruinas de un pequeño edificio con planta en forma de cruz de 12 por 14 metros, cuyos restos alcanzan una altura máxima de 4 metros, que se encuentra localizado al sureste del casco urbano del municipio de Sádaba (Zaragoza), junto al Canal de las Bardenas. A pesar de esta denominación, en la actualidad se considera que se trata de un mausoleo de época romana.

[Z_Sadaba_Mausoleo] Documentación geométrica del mausoleo romano de «La Sinagoga» (Sádaba, Zaragoza) (II)

[ES] Se conoce como la «Sinagoga» de Sádaba a las ruinas de un pequeño edificio con planta en forma de cruz de 12 por 14 metros, cuyos restos alcanzan una altura máxima de 4 metros, que se encuentra localizado al sureste del casco urbano del municipio de Sádaba (Zaragoza), junto al Canal de las Bardenas. A pesar de esta denominación, en la actualidad se considera que se trata de un mausoleo de época romana. La documentación realizada incluye una red de coordenadas absolutas obtenidas por técnicas GNSS y un volumétrico por topografía clásica. Asimismo se ha generado un modelo 3D mallado con texturas fotográficas a partir de fotografías.

[A_Llodio_Goikoetxea] Documentación geométrica de los restos de una prensa de sidra en el Caserío Goikoetxea, barrio de Isusi (Laudio/Llodio, Álava)

[ES] Los restos corresponden a un agujero que se han encontrado en la excavación del pórtico y que se relaciona con un posible poste y un pilar de madera en el interior del caserío que parece una reutilización de los elementos de la antigua prensa.

Self-Organized Criticality, Plasticity and Sensorimotor Coupling. Explorations with a Neurorobotic Model in a Behavioural Preference Task

During the last two decades, analysis of 1/f noise in cognitive science has led to a considerable progress in the way we understand the organization of our mental life. However, there is still a lack of specific models providing explanations of how 1/f noise is generated in coupled brain-body-environment systems, since existing models and experiments typically target either externally observable behaviour or isolated neuronal systems but do not address the interplay between neuronal mechanisms and sensorimotor dynamics. We present a conceptual model of a minimal neurorobotic agent solving a behavioural task that makes it possible to relate mechanistic (neurodynamic) and behavioural levels of description. The model consists of a simulated robot controlled by a network of Kuramoto oscillators with homeostatic plasticity and the ability to develop behavioural preferences mediated by sensorimotor patterns. With only three oscillators, this simple model displays self-organized criticality in the form of robust 1/f noise and a wide multifractal spectrum. We show that the emergence of self-organized criticality and 1/f noise in our model is the result of three simultaneous conditions: a) non-linear interaction dynamics capable of generating stable collective patterns, b) internal plastic mechanisms modulating the sensorimotor flows, and c) strong sensorimotor coupling with the environment that induces transient metastable neurodynamic regimes. We carry out a number of experiments to show that both synaptic plasticity and strong sensorimotor coupling play a necessary role, as constituents of self-organized criticality, in the generation of 1/f noise. The experiments also shown to be useful to test the robustness of 1/f scaling comparing the results of different techniques. We finally discuss the role of conceptual models as mediators between nomothetic and mechanistic models and how they can inform future experimental research where self-organized critically includes sensorimotor coupling among the essential interaction-dominant process giving rise to 1/f noise.