574 resultados para FRONTS
Resumo:
El presente trabajo de Tesis se ha centrado en el diseño, fabricación y caracterización de dispositivos basados en fibras de cristal fotónico infiltrado selectivamente con cristales líquidos, polímeros y una mezcla de ambos. Todos los dispositivos son sintonizables, y su área de aplicación se centra en comunicaciones ópticas y sensores. La manipulación y fusionado de fibras fotónicas, el llenado selectivo de determinadas cavidades y la alineación recíproca de fibras mantenedoras de polarización son tareas muy específicas y delicadas para las que se requieren protocolos muy estrictos. Previo a la fabricación de dispositivos ha sido necesaria por tanto una tarea de sistematización y creación de protocolos de fabricación. Una vez establecidos se ha procedido a la fabricación y caracterización de dispositivos. Los dispositivos fabricados se enumeran a continuación para posteriormente detallar una a una las singularidades de cada uno. • Interferómetros intermodales hechos a partir de una porción de fibra fotónica soldada entre dos fibras estándar, bien monomodo o PANDA (mantenedora de polarización). Estos interferómetros han sido sumergidos o bien llenados selectivamente con cristales líquidos para así sintonizar la señal interferométrica guiada a través de la fibra. • Infiltración de fibras fotónicas con cristales líquidos colestéricos con especial énfasis en la fase azul (blue phase) de estos materiales. Las moléculas de cristal líquido se autoalinean en volumen por lo que la infiltración de fibras fotónicas con estos cristales líquidos es muy interesante, pues es conocida la dificultad de alinear apropiadamente cristales líquidos dentro de cavidades micrométricas de las fibras fotónicas. • Grabación de redes holográficas de forma selectiva en las cavidades de una fibra fotónica. Estas redes holográficas, llamadas POLICRYPS (POlymer-LIquid CRYstal-Polymer Slices), son redes fabricadas a base de franjas de polímero y cristal líquido alineado perpendicularmente a dichas franjas. Las franjas son a su vez perpendiculares al eje de la fibra como lo puede ser una red de Bragg convencional. El cristal líquido, al estar alineado perpendicularmente a dichos franjas y paralelo al eje de la fibra, se puede conmutar aplicando un campo eléctrico externo, modificando así el índice efectivo de la red. Se puede fabricar por lo tanto una red de Bragg sintonizable en fibra, muy útil en comunicaciones ópticas. • Llenado selectivo de fibras fotónicas con polidimetilsiloxano (PDMS), un polímero de tipo silicona. Si se realiza un llenado selectivo asimétrico se puede inducir birrefringencia en la fibra. El índice de refracción del PDMS tiene una fuerte dependencia térmica, por lo que se puede sintonizar la birrefringencia de la fibra. • Estudio teórico de llenado selectivo de fibras fotónicas con PDMS dopado con nanopartículas de plata de 5, 40 y 80 nm. Estas nanopartículas poseen un pico de absorción en torno a los 450 nm debido a resonancias superficiales localizadas de plasmones (LSPR). La resonancia del plasmon tiene una fuerte dependencia con el índice de refracción del material colindante, y al ser éste PDMS, la variación de índice de refracción se ve amplificada, obteniendo una absorción sintonizable. Se ha propuesto la fabricación de polarizadores sintonizables usando esta técnica. Como ya se ha dicho, previamente a la fabricación ha sido necesaria la protocolización de diversos procedimientos de fabricación de alta complejidad, así como protocolizar el proceso de toma de medidas para optimizar los resultados. Los procedimientos que han requerido la formulación de protocolos específicos han sido los siguientes: • Llenado selectivo de cavidades en una fibra fotónica. Dichas fibras tienen generalmente un diámetro externo de 125 μm, y sus cavidades son de entre 5 y 10 μm de diámetro. Se han desarrollado tres técnicas diferentes para el llenado/bloqueado selectivo, pudiéndose combinar varios protocolos para la optimización del proceso. Las técnicas son las siguientes: o Llenado y bloqueado con un prepolímero. Dicho prepolímero, también llamado adhesivo óptico, está inicialmente en estado líquido y posee una cierta viscosidad. Las cavidades de la fibra fotónica que se desea llenar o bloquear poseen un diámetro diferente al resto, por lo que en el proceso de llenado aparecen dos frentes de llenado dependientes de su diámetro. A mayor diámetro, mayor velocidad de llenado. Polimerizando cuando existe dicha diferencia en los frentes se puede cortar por medio, obteniendo así una fibra parcialmente bloqueada. o Colapsamiento de las cavidades de menor diámetro mediante aplicación de calor. El calor producido por un arco voltaico de una soldadora de fibra estándar fusiona el material exterior de la fibra produciendo el colapsamiento de las cavidades de menor diámetro. En esta técnica también es necesaria una diferencia de diámetros en las cavidades de la fibra. o Bloqueo una a una de las cavidades de la fibra fotónica con adhesivo óptico. Este procedimiento es muy laborioso y requiere mucha precisión. Con este sistema se pueden bloquear las cavidades deseadas de una fibra sin importar su diámetro. • Alineación de una fuente de luz linealmente polarizada con una fibra mantenedora de polarización ya sea PANDA o fotónica. Así mismo también se han alineado entre sí fibras mantenedoras de polarización, para que sus ejes rápidos se fusionen paralelos y así el estado de polarización de la luz guiada se mantenga. • Sistematización de toma de medidas para caracterizar los interferómetros modales. Éstos son altamente sensibles a diversas variables por lo que el proceso de medida es complejo. Se deben aislar variables de forma estrictamente controlada. Aunque todos los dispositivos tienen en común el llenado selectivo de cavidades en una fibra fotónica cada dispositivo tiene sus peculiaridades, que van a ser explicadas a continuación. ABSTRACT The present Thesis has been centered in the design, fabrication and characterization of devices based on photonic crystal fibers selectively filled with liquid crystals, polymers and a mixture of both. All devices are tunable and their work field is optical communications and sensing The handling and splicing of photonic crystal fibers, the selective filling of their holes and the aligning of polarization maintaining fibers are very specific and delicate tasks for which very strict protocols are required. Before the fabrication of devices has therefore been necessary task systematization and creation of manufacturing protocols. Once established we have proceeded to the fabrication and characterization of devices. The fabricated devices are listed below and their peculiarities are detailed one by one: • Intermodal interferometers made with a portion of photonic crystal fiber spliced between two optical communication fiber pigtails, either single mode or PANDA (polarization-maintaining) fiber. These interferometers have been submerged or selectively filled with liquid crystals to tune the interferometric guided signal. • Infiltration of photonic fibers with cholesteric liquid crystals with special emphasis on their blue phase (blue phase). The liquid crystal molecules are self-aligning in volume so the infiltration of photonic fibers with these liquid crystals is very interesting. It is notoriously difficult to properly align liquid crystals within micron cavities such as photonic fibers. • Selectively recording of holographic gratings in the holes of photonic crystal fibers. These holographic gratings, called POLICRYPS (POlymer-LIquid CRYstal-Polymes Slices), are based on walls made of polymer and liquid crystal aligned perpendicular to them. These walls are perpendicular to the axis of the fiber as it can be a conventional Bragg grating. The liquid crystal is aligned perpendicular to the walls and parallel to the fiber axis, and can be switched by applying an external electric field and thus change the effective index of the grating. It is thus possible to manufacture a tunable Bragg grating fiber, useful in optical communications. •Asymmetrically selective filling of photonic crystal fibers with a silicone polymer like called polydimethylsiloxane (PDMS) to induce birefringence in the fiber. The refractive index of PDMS has temperature dependence, so that the birefringence of the fiber can be tuned. • Theoretical study of photonic crystal fibers selectively filled with PDMS doped with silver nanoparticles of 5, 40 and 80 nm. These nanoparticles have an absorption peak around 450 nm due to localized surface plasmon resonances (LSPR). Plasmon resonance has a strong dependence on the refractive index of the adjacent material, and as this is PDMS, the refractive index variation is amplified, obtaining a tunable absorption. Fabrication of tunable polarizers using this technique has been proposed. Before starting the fabrication, it has been necessary to optimize several very delicate procedures and different protocols have been designed. The most delicate procedures are as follows: • Selective filling of holes in a photonic crystal fiber. These fibers generally have an outer diameter of 125 μm, and their holes have a diameter around between 5 and 10 μm. It has been developed three different techniques for filling / selective blocking, and they can be combined for process optimization. The techniques are: o Filling and blocked with a prepolymer. This prepolymer also called optical adhesive is initially in liquid state and has a certain viscosity. The holes of the photonic crystal fiber that are desired to be filled or blocked should have a different diameter, so that in the filling process appear two different fronts depending on the hole diameter. The holes with larger diameter are filled faster. Then the adhesive is polymerized when there is such a difference on the front. A partially blocked fiber is obtained cutting between fronts. o Collapsing of holes of smaller diameter by application of heat. The heat produced by an arc of a standard fusion splicer fuses the outer fiber material producing the collapsing of the cavities of smaller diameter. In this technique also you need a difference of diameters in the fiber holes. o Blocking one by one the holes of photonic crystal fiber with optical adhesive. This procedure is very laborious and requires great precision. This system can block unwanted cavities regardless fiber diameter. • Aligning a linearly polarized light source with a polarization-maintaining fiber (either a PANDA fiber as a photonic crystal fiber). It is needed also an aligning between polarization-maintaining fibers, so that their fast axes parallel merge and that is state of polarization of light guided is maintained. • Systematization of taking measurements to characterize the modal interferometers. These are highly sensitive to several variables so the measurement process is very complicated. Variables must be fixed in a very controlled manner. Although all devices have the common characteristic of being selectively filled PCFs with some kind of material, each one has his own peculiarities, which are explained below.
Resumo:
El objetivo de esta tesis es la caracterización de la generación térmica representativa de la existente en la realidad, para posteriormente proceder a su modelización y simulación integrándolas en una red eléctrica tipo y llevar a cabo estudios de optimización multiobjetivo económico medioambiental. Para ello, en primera instancia se analiza el contexto energético y eléctrico actual, y más concretamente el peninsular, en el que habiendo desaparecido las centrales de fuelóleo, sólo quedan ciclos combinados y centrales de carbón de distinto rango. Seguidamente se lleva a cabo un análisis de los principales impactos medioambientales de las centrales eléctricas basadas en combustión, representados sobre todo por sus emisiones de CO2, SO2 y NOx, de las medidas de control y mitigación de las mismas y de la normativa que les aplica. A continuación, a partir de las características de los combustibles y de la información de los consumos específicos, se caracterizan los grupos térmicos frente a las funciones relevantes que definen su comportamiento energético, económico y medioambiental, en términos de funciones de salida horarias dependiendo de la carga. Se tiene en cuenta la posibilidad de desnitrificación y desulfuración. Dado que las funciones objetivo son múltiples, y que están en conflicto unas con otras, se ha optado por usar métodos multiobjetivo que son capaces de identificar el contorno de puntos óptimos o frente de Pareto, en los que tomando una solución no existe otra que lo mejore en alguna de las funciones objetivo sin empeorarlo en otra. Se analizaron varios métodos de optimización multiobjetivo y se seleccionó el de las ε constraint, capaz de encontrar frentes no convexos y cuya optimalidad estricta se puede comprobar. Se integró una representación equilibrada de centrales de antracita, hulla nacional e importada, lignito y ciclos combinados en la red tipo IEEE-57, en la que se puede trabajar con siete centrales sin distorsionar demasiado las potencias nominales reales de los grupos, y se programó en Matlab la resolución de flujos óptimos de carga en alterna con el método multiobjetivo integrado. Se identifican los frentes de Pareto de las combinaciones de coste y cada uno de los tres tipos de emisión, y también el de los cuatro objetivos juntos, obteniendo los resultados de costes óptimos del sistema para todo el rango de emisiones. Se valora cuánto le cuesta al sistema reducir una tonelada adicional de cualquier tipo de emisión a base de desplazarse a combinaciones de generación más limpias. Los puntos encontrados aseguran que bajo unas determinadas emisiones no pueden ser mejorados económicamente, o que atendiendo a ese coste no se puede reducir más allá el sistema en lo relativo a emisiones. También se indica cómo usar los frentes de Pareto para trazar estrategias óptimas de producción ante cambios horarios de carga. ABSTRACT The aim of this thesis is the characterization of electrical generation based on combustion processes representative of the actual power plants, for the latter modelling and simulation of an electrical grid and the development of economic- environmental multiobjective optimization studies. In this line, the first step taken is the analysis of the current energetic and electrical framework, focused on the peninsular one, where the fuel power plants have been shut down, and the only ones remaining are coal units of different types and combined cycle. Then it is carried out an analysis of the main environmental impacts of the thermal power plants, represented basically by the emissions of CO2, SO2 y NOx, their control and reduction measures and the applicable regulations. Next, based on the combustibles properties and the information about the units heat rates, the different power plants are characterized in relation to the outstanding functions that define their energy, economic and environmental behaviour, in terms of hourly output functions depending on their load. Optional denitrification and desulfurization is considered. Given that there are multiple objectives, and that they go in conflictive directions, it has been decided the use of multiobjective techniques, that have the ability of identifying the optimal points set, which is called the Pareto front, where taken a solution there will be no other point that can beat the former in an objective without worsening it in another objective. Several multiobjective optimization methods were analysed and pondered, selecting the ε constraint technique, which is able to find no convex fronts and it is opened to be tested to prove the strict Pareto optimality of the obtained solutions. A balanced representation of the thermal power plants, formed by anthracite, lignite, bituminous national and imported coals and combined cycle, was integrated in the IEEE-57 network case. This system was selected because it deals with a total power that will admit seven units without distorting significantly the actual size of the power plants. Next, an AC optimal power flow with the multiobjective method implemented in the routines was programmed. The Pareto fronts of the combination of operative costs with each of the three emissions functions were found, and also the front of all of them together. The optimal production costs of the system for all the emissions range were obtained. It is also evaluated the cost of reducing an additional emission ton of any of the emissions when the optimal production mix is displaced towards cleaner points. The obtained solutions assure that under a determined level of emissions they cannot be improved economically or, in the other way, at a determined cost it cannot be found points of lesser emissions. The Pareto fronts are also applied for the search of optimal strategic paths to follow the hourly load changes.
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Using a PCR approach we have isolated racF1, a novel member of the Rho family in Dictyostelium. The racF1 gene encodes a protein of 193 amino acids and is constitutively expressed throughout the Dictyostelium life cycle. Highest identity (94%) was found to a RacF2 isoform, to Dictyostelium Rac1A, Rac1B, and Rac1C (70%), and to Rac proteins of animal species (64–69%). To investigate the role of RacF1 in cytoskeleton-dependent processes, we have fused it at its amino-terminus with green fluorescent protein (GFP) and studied the dynamics of subcellular redistribution using a confocal laser scanning microscope and a double-view microscope system. GFP–RacF1 was homogeneously distributed in the cytosol and accumulated at the plasma membrane, especially at regions of transient intercellular contacts. GFP–RacF1 also localized transiently to macropinosomes and phagocytic cups and was gradually released within <1 min after formation of the endocytic vesicle or the phagosome, respectively. On stimulation with cAMP, no enrichment of GFP–RacF1 was observed in leading fronts, from which it was found to be initially excluded. Cell lines were obtained using homologous recombination that expressed a truncated racF1 gene lacking sequences encoding the carboxyl-terminal region responsible for membrane targeting. These cells displayed normal phagocytosis, endocytosis, and exocytosis rates. Our results suggest that RacF1 associates with dynamic structures that are formed during pinocytosis and phagocytosis. Although RacF1 appears not to be essential, it might act in concert and/or share functions with other members of the Rho family in the regulation of a subset of cytoskeletal rearrangements that are required for these processes.
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We have developed a fluorimetric assay with the use of the dye FM1-43 to determine the rate at which Dictyostelium amoebae endocytose their surface membrane. Our results show that they do so about once each 4–10 min. A clathrin null mutant takes its surface up only ∼30% more slowly, showing that this membrane uptake cannot be caused by clathrin-coated vesicles. Surprisingly, Ax2 and its parent, NC4, which differ in their rates of fluid-phase internalization by ∼60-fold, take up their surfaces at the same rates. These results show that, in axenic cells, the uptake of fluid and of surface area are separate processes. The large activity of this new endocytic cycle in both Ax2 and NC4 amoebae appears capable of delivering sufficient new surface area to advance the cells’ fronts during migration.
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We give conditions that rule out formation of sharp fronts for certain two-dimensional incompressible flows. We show that a necessary condition of having a sharp front is that the flow has to have uncontrolled velocity growth. In the case of the quasi-geostrophic equation and two-dimensional Euler equation, we obtain estimates on the formation of semi-uniform fronts.
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Complex three-dimensional waves of excitation can explain the observed cell movement pattern in Dictyostelium slugs. Here we show that these three-dimensional waves can be produced by a realistic model for the cAMP relay system [Martiel, J. L. & Goldbeter, A. (1987) Biophys J. 52, 807-828]. The conversion of scroll waves in the prestalk zone of the slug into planar wave fronts in the prespore zone can result from a smaller fraction of relaying cells in the prespore zone. Further, we show that the cAMP concentrations to which cells in a slug are exposed over time display a simple pattern, despite the complex spatial geometry of the waves. This cAMP distribution agrees well with observed patterns of cAMP-regulated cell type-specific gene expression. The core of the spiral, which is a region of low cAMP concentration, might direct expression of stalk-specific genes during culmination.
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La singular coyuntura de los años 1814-1816 enmarca la actividad del Congreso de Tucumán. Ante un escenario internacional de restauración monárquica y un contexto rioplatense signado por el levantamiento de Fontezuelas, el Congreso y el nuevo director supremo emanado del mismo dirigen sus acciones a consolidar su legitimidad y garantizar la gobernabilidad de los pueblos asistentes. Las sesiones secretas actúan como caja de resonancia de los múltiples frentes de intervención. El presente trabajo permite realizar un balance historiográfico del estado actual de los estudios sobre el Congreso en su etapa tucumana, aportando una lectura desde una fuente poco explorada
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O presente trabalho tem como propósito principal perspectivar analiticamente como os processos de pedagogização forjam e governam determinados espaços e espacialidades. Para tanto, partimos do pressuposto de que as práticas sociais são moduladas por jogos de força que as criam e recriam espacialmente, sobretudo por meio de mecanismos pedagogizantes que ultrapassam o âmbito educacional formal, alastrando-se cada vez mais no cenário urbano contemporâneo. Assim, propomo-nos a analisar a relação entre educação e produção de espaços/espacialidades nas práticas instituídas no Parque Ibirapuera-SP. A investigação tem como marco teórico o pensamento de Michel Foucault, além de mobilizar os trabalhos de Doreen Massey, Edward Soja, Henri Lefebvre, David Harvey e Rodrigo Valverde. A cartografia realizada pleiteia-se, portanto, uma derivação da perspectiva arqueogenealógica foucaultiana. De acordo com tal referencial, assinalaram-se práticas que permitiram dimensionar as transformações pedagógicas e espaciais do Parque desde sua criação, apontando para os modos como atualmente se perfaz o governamento das espacialidades e, em igual medida, as contracondutas aí tornadas possíveis. Além do levantamento bibliográfico, operamos segundo duas frentes de trabalho complementares: em primeiro lugar, a análise de documentos oficiais acerca do Parque, dos Processos da Comissão do IV Centenário da Cidade de São Paulo e de discursos jornalísticos veiculados a seu respeito pelo jornal O Estado de S. Paulo em diferentes décadas; em segundo, a observação e o registro de práticas contemporâneas ali em curso. Os resultados evidenciam uma racionalidade vincada em práticas de pedagogização, e estas, aliadas a tecnologias específicas de governamento dos espaços. Um cenário que apresenta lógicas de governo heterogêneas, que coexistem através do tempo, ajustando-se, desajustando-se ou alterando-se. Não obstante, um campo vivo de forças, de sujeitos e práticas de subjetivação. A história arqueogenealógica do Parque, assim como dos diferentes mecanismos pedagogizantes ali em voga, possibilitou deslindar o trânsito dos espaços e o governo das espacialidades pela população que dele faz uso, além das diferentes contestações dos arranjos até então configurados, demarcando traços fugidios de uma heterotopia urbana.
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Avui en dia l’educació és objecte de debat per a la societat en general i per a les famílies en particular. Són molts els fronts que educadors, mestres, psicòlegs, pedagogs i la resta de persones relacionades amb el sistema escolar tenim oberts, i molts els qüestionaments que sobre el nostre treball es realitzen. En aquesta pràctica reflexionarem sobre un aspecte important: En són beneficioses per al desenvolupament infantil les escoles infantils de 0 a 3 anys?
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In typical theoretical or experimental studies of heat migration in discrete fractures, conduction and thermal dispersion are commonly neglected from the fracture heat transport equation, assuming heat conduction into the matrix is predominant. In this study analytical and numerical models are used to investigate the significance of conduction and thermal dispersion in the plane of the fracture for a point and line sources geometries. The analytical models account for advective, conductive and dispersive heat transport in both the longitudinal and transverse directions in the fracture. The heat transport in the fracture is coupled with a matrix equation in which heat is conducted in the direction perpendicular to the fracture. In the numerical model, the governing heat transport processes are the same as the analytical models; however, the matrix conduction is considered in both longitudinal and transverse directions. Firstly, we demonstrate that longitudinal conduction and dispersion are critical processes that affect heat transport in fractured rock environments, especially for small apertures (eg. 100 μm or less), high flow rate conditions (eg. velocity greater than 50 m/day) and early time (eg. less than 10 days). Secondly, transverse thermal dispersion in the fracture plane is also observed to be an important transport process leading to retardation of the migrating heat front particularly at late time (eg. after 40 days of hot water injection). Solutions which neglect dispersion in the transverse direction underestimate the locations of heat fronts at late time. Finally, this study also suggests that the geometry of the heat sources has significant effects on the heat transport in the system. For example, the effects of dispersion in the fracture are observed to decrease when the width of the heat source expands.
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Introduction. Since the 25th of January 2011 revolution the Egyptian economy has been suffering on all fronts. Almost all the economic indicators have been pointing towards a deteriorating situation, and in many cases have reached the trough. Yet, the economy is still surviving. This is mainly due to the unprecedented support of some of Arab Gulf countries, whose unconditional aid has helped to mitigate the deteriorating economic conditions. The economic challenges facing Egypt have been exacerbated after the 20th of January revolution mainly because of the deteriorating political and security conditions which have interrupted the functioning of the economy. Yet, this is not to say that revolution has caused these challenges. In fact, the challenges that the Egyptian has been facing have deep roots in its socio-political-economic context, which this paper aims to explain. The revolution and its aftermath have brought to the forefront challenges which have always been mitigated by short-term solutions that never dealt seriously with their roots. Moreover, the revolution has brought additional problems associated with the macroeconomic imbalances. As a result, the challenges became more complex especially in light of the need to balance the social and economic aspects. The paper proceeds as follows; in section one we pinpoint the main challenges faced by Egypt where we identify the symptoms and causes of such challenges. In section two we discuss the roots of such challenges. Finally, we conclude and provide our understanding of how Egypt is expected to face its challenges in the near future.
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Europe is in need of a new leadership capacity able to recreate stronger European unity in the external and internal fronts. Otherwise, anti-European forces will increase their influence and presence in European governments and EU institutions with large implications for the direction of European integration. This will be the central concern in making a first short assessment of the recent process of building European leadership capacity for the next five years to come. This assessment will particularly focus on the choice of the President of the European Commission, of the President of the European Council and, finally of the members of the European Commission.
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Capital Markets Union (CMU) is a welcome initiative. It could augment economic risk sharing, set the right conditions for more dynamic development of risk capital for high-growth firms and improve choices and returns for savers. This offers major potential for benefits in terms of jobs, growth and financial resilience. • CMU cannot be a short-term cyclical instrument to replace subdued bank lending, because financial ecosystems change slowly. Shifting financial intermediation towards capital markets and increasing cross-border integration will require action on multiple fronts, including increasing the transparency, reliability and comparability of information and addressing financial stability concerns. Some quick wins might be available but CMU’s real potential can only be achieved with a long-term structural policy agenda. • To sustain the current momentum, the EU should first commit to a limited number of key reforms, including more integrated accounting enforcement and supervision of audit firms. Second, it should set up autonomous taskforces to prepare proposals on the more complex issues: corporate credit information, financial infrastructure, insolvency, financial investment taxation and the retrospective review of recent capital markets regulation. The aim should be substantial legislative implementation by the end of the current EU parliamentary term.
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FOREWORD. When one looks at the present state of the CSDP, one cannot help but look on with disenchantment at the energy that appears to have abandoned both institutions and Member States. Commentators increasingly take for granted that nothing much should be expected from this field of EU policy. The reasons for this state of mind are well known: the recent economic and financial strains, which have impacted all EU action since 2008, means that most of the Member States will struggle to keep their defence budgets at their present level in the future, and we may even see reductions. Furthermore, and to put it mildly, most of the recent CSDP operations have also experienced a lack of enthusiasm. Adding to this overall trend, the EU is far from presenting a common vision of what security and defence should really mean. Many of the Member States do not want to be involved in all of today’s international turmoils, and they rarely share the strategic culture which inspires those Member States who see themselves as having special responsibilities in dealing with these crises. In the end it may be that Member States diverge fundamentally on the simple question of whether it is relevant for the EU to engage in most of the ‘hot’ crises Europe faces; many prefer to see Europe as a soft power, mostly dedicated to intervening on less dramatic fronts and more inclined to mend than to fight. For whatever reason given, it remains that if there is a lack of common understanding on what CSDP should really be about, it should not come as a surprise if this policy is presently in stalemate. As an additional blow, the Ukrainian crisis, which dragged on for the whole of last year, could only add to the downward spiral the EU has been experiencing, with a new Russia aggressively confronting Europe in a manner not too distant from the Cold War days. This attitude has triggered the natural reaction among EU Member States to seek reassurances from NATO about their own national security. Coupled with the return of France a few years ago into the integrated military command, NATO’s renewed relevance has sent a strong message to Europe about the military organisation’s credibility with regard to collective defence. Surprisingly, this overall trend was gathering momentum at the same time as other more positive developments. The European Council of December 2013 dedicated its main session to CSDP: it underlined Europe’s role as a ‘security provider’ while adopting a very ambitious road map for Europe in all possible dimensions of the security sector. Hence the impression of a genuine boost to all EU institutions, which have been invited to join efforts and give CSDP a reinvigorated efficiency. In the same way, the increasing instability in Europe’s neighbourhood has also called for more EU operations: most recently in Iraq, Libya, Northern Nigeria or South Sudan. Pressure for further EU engagement has been one of the most constant features of the discussions taking place around these crises. Moreover, a growing number of EU partners in Asia, Latin America or Eastern Europe have shown a renewed eagerness to join CSDP missions in what sounds like a vote of confidence for EU capacities. What kind of conclusion should be drawn from this contradictory situation? Probably that the EU has much more potential than it can sometimes figure out itself, if only it would be ready to adapt to the new global realities. But, more than anything else, an enhanced CSDP needs from all Member States strong political will and a clear vision of what they want this policy to be. Without this indispensable ingredient CSDP may continue to run its course, as it does today. It may even grow in efficiency but it will keep lacking the one resource that would definitely help it overcome all the present shortcomings that have prevented Europe from finding its true role and mission through the CSDP. Member States remain central to EU security and defence policy. This is why this collection of essays is so valuable for assessing in no uncertain way the long road that lies ahead for any progress to be made. Pierre VIMONT Senior Associate at Carnegie Europe Former Executive Secretary-General of the European External Action Service
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Against the background of the rapidly growing number of asylum-seekers, Daniel Gros argues in this CEPS Commentary that the EU needs to take action on two fronts. First, member countries must urgently boost their capacity to deal with asylum applications, so that they can quickly identify those who truly deserve protection. Second, the EU needs to improve burden-sharing in providing shelter for those who gain asylum. In his view, international law – and basic morality – demands nothing less.