La Formación de Aviadores de la República: Las Promociones de la URSS

Dins el marc de la historiografia de la Guerra Civil espanyola dedicada a la guerra aèria encara avui dia existeixen importants buits per omplir. Sens dubte, un d’aquests és el relatiu a la formació de pilots republicans i als cursos realitzats a Espanya, França i la Unió Soviètica. En aquest article, i gràcies al diari d’un alumne pilot de la 3a promoció d’espanyols instruïts a la URSS, es detallen alguns aspectes que s’afegeixen a les escasses investigacions relatives a la instrucció i aprenentatge d’aquests joves aspirants. A més d’aquest diari, única font escrita que ens ha arribat sobre aquest tema, l’autor també ens parla de la influència del Partit Comunista dins les forces aèries republicanes

Climate extremes can drive biological assemblages to early successional stages compared to several mild disturbances

Extreme climatic events have a major role in the structuring of biological communities, and their occurrence is expected to increase due to climate change. Here I use a manipulative approach to test the effects of extreme storm events on rocky mid-shore assemblages. This study shows that an extreme storm can cause more negative effects than several mild storms, primarily by bringing the biological assemblages towards early stages of succession. This finding contrasts with the effects of clustering of climatic events due to climate change, which are expected to mitigate its ecological impacts. Thus, the ecological consequences of climatic events that are influenced by climate change may have contrasting effects depending on the features that are considered. These results have relevant implications in the forecasting of the ecological consequences of climate change and should be considered when designing measures to mitigate its effects.I have been financially supported by a postdoctoral grant from the Alfonso Martín Escudero Foundation and the University of Alicante (reference: GRE13-18), both from Spain

LA Escuela de Aviación Libertaria de Barcelona

The disruption caused in military aviation by military uprising of 18th July 1936 and the need of airmen to be incorporated at the front caused the opening of aviation training schools in the government territory. In Barcelona, the CNT-FAI promoted the creating of a flying school and the acquisition of material in order to obtain an own aircraft, but collided with the interests and objectives of the Generalitat and the Ministry of the Navy and Air Indalecio Prieto.La desorganización provocada en la Aviación Militar por la sublevación militar del 18 de julio de 1936 y la necesidad de aviadores que se incorporaran al frente dio lugar a la apertura de escuelas de formación aeronáutica en el territorio gubernamental. En Barcelona, la CNT-FAI promovió la creación de una escuela aeronáutica y la adquisición de material con el fin de dotarse de una aviación propia, pero chocó con los intereses y objetivos de la propia Generalitat y el Ministerio de Marina y Aire de Indalecio Prieto

Dynamics and collective phenomena of social systems

This thesis focuses on the study of social systems through methods of theoretical physics, in particular proceedings of statistical physics and complex systems, as well as mathematical tools like game theory and complex networks. There already ex- ists predictive and analysis methods to address these problems in sociology, but the contribution of physics provides new perspectives and complementary and powerful tools. This approach is particularly useful in problems involving stochastic aspects and nonlinear dynamics. The contribution of physics to social systems provides not only prediction procedures, but new insights, especially in the study of emergent properties that arise from holistic approaches. We study social systems by introducing different agent-based models (ABM). When possible, the models are analyzed using mathematical methods of physics, in order to achieve analytical solutions. In addition to a theoretical approach, experi- mental treatment is performed via computer simulations both through Monte Carlo methods and deterministic or mixed procedures. This working method has proved very fruitful for the study of several open problems. The book is structured as follows. This introduction presents the mathematical formalisms used in the investigations, which are structured in two parts: in part I we deal with the emergence of cooperation, while in part II we analyze cultural dynamics under the perspective of tolerance

Nonviscous Modes of Viscoelastically Damped Vibrating Systems

Nonviscously damped vibrating systems are characterized by dissipative mechanisms depending on the time history of the response velocity, introduced in the physical models using convolution integrals involving hereditary kernel functions. One of the most used damping viscoelastic models is Biot’s model, whose hereditary functions are assumed to be exponential kernels. The free-motion equations of these types of nonviscous systems lead to a nonlinear eigenvalue problem enclosing certain number of the so-called nonviscous modes with nonoscillatory nature. Traditionally, the nonviscous modes (eigenvalues and eigenvectors) for nonproportional systems have been computed using the state-space approach, computationally expensive. This number of real eigenvalues is directly related to the rank of the damping matrices associated with the exponential kernels. The state-space approach has traditionally been used up to now as the only method to compute the nonviscous modes for nonproportionally damped systems. Motivated by this open problem, we propose in this chapter to describe the available numerical methods for classically damped systems and present the recent methods for nonclassically damped systems. It is shown that the problem of finding the nonviscous modes can be reduced to solve as a set of linear eigenvalue problems. The presented methods are compared through a numerical example

Estudio de la reactividad de sistemas insaturados frente a zwitteriones tipo koshar. Aplicaciones sintéticas

Koshar’s zwitterions have not been studied since 1976. Fortunately, in 2013 Yanai’s group rediscovered them, improving their synthesis and performing a deep analysis of their properties and characteristics. This work was the starting point of a new research line in our group and hasled to the present PhD Thesis. The in situ formation of the molecule Tf2C=CH2 in solution, from Koshar’s zwitterions, made us consider the study of its behavior and synthetic utility with different unsaturated groups and heterocyclic systems. On the other hand, the development of cyclization methodologies to obtain highly tensioned rings is of great interest. Cyclobutenes, cyclobutenones and cyclobutenols are included in this group. These four-membered carbocycles are molecules with great synthetic utility but difficult to access; and particularly if their formation is required with chemo-, regio- and stereoselectivity..

As empresas na Sociedade da informação

Actualmente, a informação e a forma como ela é trabalhada, como circula e é difundida, tem vindo a tornar-se cada vez mais um instrumento de gestão, constituindo uma necessidade básica para a decisão, realização e controlo das actividades e fundamental no sucesso das organizações (públicas ou privadas). Vivemos uma era de mudança socio-económica, suportada em meios digitais e em processos de inovação com apelo à criatividade, na procura da diferenciação de novos produtos, processos e serviços, que se materializa na formação da chamada "Sociedade da Informação" baseada no conhecimento. A Sociedade da Informação, recorrendo crescentemente a redes digitais de informação, no domínio da actividade económica e do bem-estar social, resulta do desenvolvimento das novas tecnologias da informação, do audiovisual e das comunicações, com impactos profundos em vários domínios, como por exemplo, no trabalho, na educação, na ciência, na saúde, no lazer, nos transportes e no ambiente. O tema "Sociedade da Informação" tem sido objecto de um amplo debate nacional promovido pelo Ministério da Ciência e Tecnologia, tendo sido aprovado em Abril de 1997, em Conselho de Ministros, o chamado "Livro Verde para a Sociedade da Informação em Portugal", documento imprescindível à sua compreensão e disponível em formato electrónico no servidor "World Wide Web" da "Missão para a Sociedade da Informação" em "http://www.missao-si.mct.pt"

The joint influence of competition and mutualism on the biodiversity of mutualistic ecosystems

Relations among species in ecosystems can be represented by complex networks where both negative (competition) and positive (mutualism) interactions are concurrently present. Recently, it has been shown that many ecosystems can be cast into mutualistic networks, and that nestedness reduces effective inter-species competition, thus facilitating mutually beneficial interactions and increasing the number of coexisting species or the biodiversity. However, current approaches neglect the structure of inter-species competition by adopting a mean-field perspective that does not deal with competitive interactions properly. Here, we introduce a framework based on the concept of multilayer networks, which naturally accounts for both mutualism and competition. Hence, we abandon the mean field hypothesis and show, through a dynamical population model and numerical simulations, that there is an intricate relation between competition and mutualism. Specifically, we show that when all interactions are taken into account, mutualism does not have the same consequences on the evolution of specialist and generalist species. This leads to a non-trivial profile of biodiversity in the parameter space of competition and mutualism. Our findings emphasize how the simultaneous consideration of positive and negative interactions can contribute to our understanding of the delicate trade-offs between topology and biodiversity in ecosystems and call for a reconsideration of previous findings in theoretical ecology, as they may affect the structural and dynamical stability of mutualistic systems.Comment: 11 pages. Submitted for publicatio

Los cautivos en la frontera araucana.

Sin resume