The innermost regions of the jet in NRAO 150. Wobbling or internal rotation?

NRAO 150 is a very bright millimeter to radio quasar at redshift $z$=1.52 for which ultra-high-resolution VLBI monitoring has revealed a counter-clockwise jet-position-angle wobbling at an angular speed $\sim11^{\circ}$/yr in the innermost regions of the jet. In this paper we present new total and linearly polarized VLBA images at 43 GHz extending previous studies to cover the evolution of the jet in NRAO 150 between 2006 and early 2009. We propose a new scenario to explain the counter-clockwise rotation of the jet position angle based on a helical motion of the components in a jet viewed faced-on. This alternative scenario is compatible with the interpretation suggested in previous works once the indetermination of the absolute position of the self-calibrated VLBI images is taken into account. Fitting of the jet components motion to a simple internal rotation kinematical model shows that this scenario is a likely alternative explanation for the behavior of the innermost regions in the jet of NRAO 150.Comment: 5 pages, 4 figures, Presented in 'The Innermost Regions of Relativistic Jets and Their Magnetic Fields' conference. Granada, Spain, 201

Influence of sustainability practices and green image on the re-visit intention of small and medium-size towns

This study set a model to predict the e ect of corporate social responsibility and green image on visit intention in small and medium-size towns (SMST). At present, there is a keen social awareness towards environmental problems, and cities are required to reduce their ecological footprint and make more sustainable use of natural resources. Increasingly, tourists are considering “green options” in their decision making. The questionnaire responses, obtained from a sample of 221 tourism in Malaga town (Spain) were analyzed using a Structural Equation Modelling (SEM) to test the research hypothesis related to the positive influence of sustainability practices, green image, trust with the intention of revisiting related to the loyalty of the destination. This study shows that there is a positive relationship between sustainability practices and re-visit intention and between the green image and re-visit intention, both directly and indirectly, through trust. Also, the fact that this relationship is more significant if it is part of the green image than if it is part of sustainability actions. To practice, this study provides managerial implications to help executives adopt green actions, thanks to their positive e ects on tourist loyalty and the di erent way of manifesting this loyalty.info:eu-repo/semantics/publishedVersio

Technology, governance, and a sustainability model for small and medium-sized towns in Europe

New and cutting-edge technologies causing deep changes in societies, playing the role of game modifiers, and having a significant impact on global markets in small and medium-sized towns in Europe (SMSTEs) are the focus of this research. In this context, an analysis was carried out to identify the main dimensions of a model for promoting innovation in SMSTEs. The literature review on the main dimensions boosting the innovation in SMSTEs and the methodological approach was the application of a survey directed to experts on this issue. The findings from the literature review reflect that technologies, governance, and sustainability dimensions are enablers of SMSTEs’ innovation, and based on the results of the survey, a model was implemented to boost innovation, being this the major add-on of this research.info:eu-repo/semantics/publishedVersio

Power systems with high renewable energy sources: A review of inertia and frequency control strategies over time

Traditionally, inertia in power systems has been determined by considering all the rotating masses directly connected to the grid. During the last decade, the integration of renewable energy sources, mainly photovoltaic installations and wind power plants, has led to a significant dynamic characteristic change in power systems. This change is mainly due to the fact that most renewables have power electronics at the grid interface. The overall impact on stability and reliability analysis of power systems is very significant. The power systems become more dynamic and require a new set of strategies modifying traditional generation control algorithms. Indeed, renewable generation units are decoupled from the grid by electronic converters, decreasing the overall inertia of the grid. ‘Hidden inertia’, ‘synthetic inertia’ or ‘virtual inertia’ are terms currently used to represent artificial inertia created by converter control of the renewable sources. Alternative spinning reserves are then needed in the new power system with high penetration renewables, where the lack of rotating masses directly connected to the grid must be emulated to maintain an acceptable power system reliability. This paper reviews the inertia concept in terms of values and their evolution in the last decades, as well as the damping factor values. A comparison of the rotational grid inertia for traditional and current averaged generation mix scenarios is also carried out. In addition, an extensive discussion on wind and photovoltaic power plants and their contributions to inertia in terms of frequency control strategies is included in the paper.This work was supported by the Spanish Education, Culture and Sports Ministry [FPU16/04282]

Autonomy of NGOs : analysis of two NGOs in terms of how they frame their purpose

The survival requirements of non-profit organizations might increase their vulnerability to external influences and restrain their autonomy. This qualitative article examines how the NGOs Women Deliver and International Youth Alliance for Family Planning articulate their purpose through the lenses of organizational theories and smart power...Los requisitos que las organizaciones no gubernamentales (ONG) tienen para mantener su supervivencia incrementan su vulnerabilidad hacia influencias externas y limita su autonomía. Este estudio cualitativo examina mediante las teorías organizacionales y se poder inteligente cómo las organizaciones Women Deliver e International Youth Alliance for Family Planning materializan sus objetivos..

First clear evidence of quantum chaos in the bound states of an atomic nucleus

We study the spectral fluctuations of the $^{208}$Pb nucleus using the complete experimental spectrum of 151 states up to excitation energies of $6.20$ MeV recently identified at the Maier-Leibnitz-Laboratorium at Garching, Germany. For natural parity states the results are very close to the predictions of Random Matrix Theory (RMT) for the nearest-neighbor spacing distribution. A quantitative estimate of the agreement is given by the Brody parameter $\omega$, which takes the value $\omega=0$ for regular systems and $\omega \simeq 1$ for chaotic systems. We obtain $\omega=0.85 \pm 0.02$ which is, to our knowledge, the closest value to chaos ever observed in experimental bound states of nuclei. By contrast, the results for unnatural parity states are far from RMT behavior. We interpret these results as a consequence of the strength of the residual interaction in $^{208}$Pb, which, according to experimental data, is much stronger for natural than for unnatural parity states. In addition our results show that chaotic and non-chaotic nuclear states coexist in the same energy region of the spectrum.Comment: 9 pages, 1 figur

Advanced capabilities for planar X-ray systems

Mención Internacional en el título de doctorThe past decades have seen a rapid evolution towards the use of digital detectors in radiology and a more flexible robotized movement of the system components, X-ray tube and detector. This evolution opened the possibility for incorporating advanced capabilities in these planar X-ray systems, and for providing new valuable diagnostic information compared to the previous technology. Some of the current challenges for radiography are to obtain more quantitative images and to reduce the inherent superposition of tissues because of the 2D nature of the technique. Dual energy radiography, based on the acquisition of two images at different source voltages, enables a separate characterization of soft tissue and bone structures. Its benefits over conventional radiography have been proven in different applications, since it improves information content without adding significant extra acquisition time or radiation dose. In a different direction, a really disruptive advance would be to obtain 3D imaging with systems designed just for planar images. The incorporation of tomographic capabilities into these systems would have to deal with the acquisition of a limited number of projections, with non-standard geometrical configurations. This thesis presents original contributions in these two directions: dual energy radiography and 3D imaging with X-ray systems designed for planar imaging. The work is framed in a line of research of the Biomedical Imaging and Instrumentation Group from the Bioengineering and Aerospace Department of University Carlos III de Madrid working jointly with the University Hospital Gregorio Marañón, focused on the advance of radiology systems. This research line is carried out in collaboration with the group of Computer Architecture, Communications and Systems (ARCOS), from the same university, the Imaging Research Laboratory (IRL) of the University of Washington and the research center CREATIS, France. The research has a clear focus on technology transfer to the industry through the company Sedecal, a Spanish multinational among the 10 best world companies in the medical imaging field. The first contribution of this thesis is a complete novel protocol to incorporate dual energy capabilities that enable quantitative planar studies. The proposal is based on the use of a preliminary calibration with a very simple and low-cost phantom formed by two parts that represent soft tissue and bone equivalent materials. This calibration is performed automatically with no strict placement requirements. Compared to current Dual-energy X-ray Absorptiometry (DXA) systems, 1) it provides real mass-thickness values directly, enabling quantitative planar studies instead of relative comparisons, and 2) it is based on an automatic preliminary calibration without the need of interaction of an experienced technician. The second contribution is a novel protocol for the incorporation of tomographic capabilities into X-ray systems originally intended for planar imaging. For this purpose, we faced three main challenges. First, the geometrical trajectory of equipment follows non-standard circular orbits, thus posing severe difficulties for reconstruction. To handle this, the proposed protocol comprises a new geometrical calibration procedure that estimates all the system parameters per-projection. Second, the reconstruction of a limited number of projections from a reduced angular span leads to severe artifacts when using conventional reconstruction methods. To deal with these limited-view data, the protocol includes a novel advanced reconstruction method that incorporates the surface information of the sample, which can be extracted with a 3D light surface scanner. These data are introduced as an imposed constraint following the Split Bregman formulation. The restriction of the search space by exploiting the surface-based support becomes crucial for a complete recovery of the external contour of the sample and surroundings when the angular span is extremely reduced. The modular, efficient and flexible design followed for its implementation allows for the reconstruction of limited-view data with non-standard trajectories. Third, the optimization of the acquisition protocols has not yet explored with these systems. This thesis includes a study of the optimum acquisition protocols that allowed us to identify the possibilities and limitations of these planar systems. Using the surface-constrained method, it is possible to reduce the total number of projections up to 33% and the angular span down to 60 degrees. The contributions of this thesis open the way to provide depth and quantitative information very valuable for the improvement of radiological diagnosis. This could impact considerably the clinical practice, where conventional radiology is still the imaging modality most used, accounting for 80-90% of the total medical imaging exams. These advances open the possibility of new clinical applications in scenarios where 1) the reduction of the radiation dose is key, such as lung cancer screening or Pediatrics, according to the ALARA criteria (As Low As Reasonably Achievable), 2) a CT system is not usable due to movement limitations, such as during surgery or in an ICU and 3) where costs issues complicate the availability of CT systems, such as rural areas or underdeveloped countries. The results of this thesis has a clear application in the industry, since it is part of a proof of concept of the new generation of planar X-ray systems that will be commercialized worldwide by the company SEDECAL (Madrid, Spain).Los últimos años están viendo un rápido avance de los sistemas de radiología hacia el uso de detectores digitales y a una mayor flexibilidad de movimientos de los principales componentes del sistema, el tubo de rayos X y el detector. Esta evolución abre la posibilidad de incorporar capacidades avanzadas en sistemas de imagen plana por rayos X proporcionando nueva información valiosa para el diagnóstico. Dos retos en radiografía son obtener imágenes cuantitativas y reducir la superposición de tejidos debida a la naturaleza proyectiva de la técnica. La radiografía de energía dual, basada en la adquisición de dos imágenes a diferente kilovoltaje, permite obtener imágenes de tejido blando y hueso por separado. Los beneficios de esta técnica que aumenta la cantidad de información sin añadir un tiempo de adquisición o de dosis de radiación extra significativos frente al uso de radiografía convencional, han sido demostrados en diferentes aplicaciones. En otra dirección, un avance realmente disruptivo sería la obtención de imagen 3D con sistemas diseñados únicamente para imagen plana. La incorporación de capacidades tomográficas en estos sistemas tendría que lidiar con la adquisición de un número limitado de proyecciones siguiendo trayectorias no estándar. Esta tesis presenta contribuciones originales en esas dos direcciones: radiografía de energía dual e imagen 3D con sistemas de rayos X diseñados para imagen plana. El trabajo se encuadra en una línea de investigación del grupo de Imagen Biomédica e Instrumentación del Departamento de Bioingeniería e Ingeniería Aerospacial de la Universidad Carlos III de Madrid junto con el Hospital Universitario Gregorio Marañon, centrada en el avance de sistemas de radiología. Esta línea de investigación se desarollada en colaboración con el grupo Computer Architecture, Communications and Systems (ARCOS), de la misma universidad, el grupo Imaging Research Laboratory (IRL) de la Universidad de Washington y el centro de investigación CREATIS, de Francia. Se trata de una línea de investigación con un claro enfoque de transferencia tecnológica a la industria a través de la compañía SEDECAL, una multinacional española de entre las 10 líderes del mundo en el campo de la radiología. La primera contribución de esta tesis es un protocolo completo para incorporar capacidades de energía dual que permitan estudios cuantitativos de imagen plana. La propuesta se basa en una calibración previa con un maniquí simple y de bajo coste formado por dos materiales equivalentes de tejido blando y hueso respectivamente. Comparado con los sistemas actuales DXA (Dual-energy X-ray Absorptiometry), 1) proporciona valores reales de tejido atravesado, 2) se basa en una calibración automática que no requiere la interacción de un técnico con gran experiencia. La segunda contribución es un protocolo nuevo para la incorporación de capacidades tomográficas en sistemas de rayos X originariamente diseñados para imagen plana. Para ello, nos enfrentamos a tres principales dificultades. En primer lugar, las trayectorias que pueden seguir la fuente y el detector en estos sistemas no constituyen órbitas circulares estándares, lo que plantea retos importantes en la caracterización geométrica. Para solventarlo, el protocolo propuesto incluye una calibración geométrica que estima todos los parámetros geométricos del sistema para cada proyección. En segundo lugar, la reconstrucción de un número limitado de proyecciones adquiridas en un rango angular reducido da lugar a artefactos graves cuando se reconstruye con algoritmos convencionales. Para lidiar con estos datos de ángulo limitado, el protocolo incluye un nuevo método avanzado de reconstrucción que incorpora la información de superficie de la muestra, que se puede se obtener con un escáner 3D. Esta información se impone como una restricción siguiendo la formulación de Split Bregman, para compensar la falta de datos. La restricción del espacio de búsqueda a través de la explotación del soporte basado en superficie, es crucial para una recuperación completa del contorno externo de la muestra cuando el rango angular es extremadamente pequeño. El diseño modular, eficiente y flexible de la implementación propuesta permite reconstruir datos de ángulo limitado obtenidos con posiciones de fuente y detector no estándar. En tercer lugar, hasta la fecha, no se ha explorado la optimización del protocolo de adquisición con estos sistemas. Esta tesis incluye un estudio de los protocolos óptimos de adquisición que permitió identificar las posibilidades y limitaciones de estos sistemas de imagen plana. Gracias al método de reconstrucción basado en superficie, es posible reducir el número total de proyecciones hasta el 33% y el rango angular hasta 60 grados. Las contribuciones de esta tesis abren la posibilidad de proporcionar información de profundidad y cuantitativa muy valiosa para la mejora del diagnóstico radiológico. Esto podría impactar considerablemente en la práctica clínica, donde la radiología convencional es todavía la modalidad de imagen más utilizada, abarcando el 80- 90% del total de los exámenes de imagen médica. Estos avances abren la posibilidad de nuevas aplicaciones clínicas en escenarios donde 1) la reducción de la dosis de radiación es clave, como en screening de cáncer de pulmón, de acuerdo con el criterio ALARA (As Low As Reasonably Achievable), 2) no se puede usar un sistema TAC por limitaciones de movimiento como en cirugía o UCI, o 3) el coste limita la disponibilidad de sistemas TAC, como en zonas rurales o en países subdesarrollados. Los resultados de esta tesis presentan una clara aplicación industrial, ya que son parte de un prototipo de la nueva generación de sistemas planos de rayos X que serán distribuidos mundialmente por la compañía SEDECAL.This thesis has been developed as part of several research projects with public funding: - DPI2016-79075-R. ”Nuevos escenarios de tomografía por rayos X”, IP: Mónica Abella García, Ministerio de Economía y Competitividad, 01/01/2017-31/12/2019, 147.620 e. - ”Nuevos escenarios de tomografía por rayos X (NEXT) DPI2016-79075-R. Ministerio de Economía”, Industria y Competitividad. (Universidad Carlos III de Madrid). 30/12/2016-29/12/2019. 147.620 e. (…) - FP7-IMI-2012 (GA-115337), ”PreDict-TB: Model-based preclinical development of anti-tuberculosis drug combinations”. FP7-IMI - Seventh Framework Programme (EC-EFPIA). Unión Europea. (Universidad Carlos III de Madrid). 01/05/2012-31/10/2017. (…) - TEC2013-47270-R, ”Avances en Imagen Radiológica (AIR)”, Ministerio de Economía y Competitividad”, 01/01/2014-31/12/2016. IP: Mónica Abella Garcia and Manuel Desco Menéndez. 160.204 e (…) - RTC-2014-3028-1, ”Nuevos Escenarios Clínicos con Radiología Avanzada (NECRA)”, Ministerio de Economía y Competitividad, 01/06/2014-31/12/2016 IP: Mónica Abella García. 2014-2016. 219.458,96 e - IDI-20130301, ”Nuevo sistema integral de radiografía (INNPROVE: INNovative image PROcessing in medicine and VEterinary)”, IP: Mónica Abella García and Manuel Desco Menéndez. Ministerio de Economía y Competitividad. Subcontratación CDTI, 14/01/2013-31/03/2015. Total: 1.860.629e (UC3M: 325.000e). (Art. 83) - IPT-2012-0401-300000 INNPACTO 2012, ”Tecnologías para Procedimientos Intraoperatorios Seguros y Precisos. XIORT. MINECO. (Universidad Carlos III de Madrid). 01/01/2013-31/12/2015.Programa Oficial de Doctorado en Ingeniería MatemáticaPresidente: Doménec Ros Puig.- Secretario: Cyril Riddell.- Vocal: Yannick Boursie