Juvenile–adult tree associations in a continental Mediterranean ecosystem: no evidence for sustained and general facilitation at increased aridity

Question: How do tree species identity, microhabitat and water availability affect inter- and intra-specific interactions between juvenile and adult woody plants? Location: Continental Mediterranean forests in Alto Tajo Natural Park, Guadalajara, Spain. Methods: A total of 2066 juveniles and adults of four co-occurring tree species were mapped in 17 plots. The frequency of juveniles at different microhabitats and water availability levels was analysed using log-linear models. We used nearest-neighbour contingency table analysis of spatial segregation and J-functions to describe the spatial patterns. Results: We found a complex spatial pattern that varied according to species identity and microhabitat. Recruitment was more frequent in gaps for Quercus ilex, while the other three species recruited preferentially under shrubs or trees depending on the water availability level. Juveniles were not spatially associated to conspecific adults, experiencing segregation from them inmany cases. Spatial associations, both positive and negative, were more common at higher water availability levels. Conclusions: Our results do not agree with expectations from the stressgradient hypothesis, suggesting that positive interactions do not increase in importance with increasing aridity in the study ecosystem. Regeneration patterns are species-specific and depend on microhabitat characteristics and dispersal strategies. In general, juveniles do not look for conspecific adult protection. This work contributes to the understanding of species co-existence, proving the importance of considering a multispecies approach at several plots to overcome limitations of simple pair-wise comparisons in a limited number of sites.

Responses of riparian guilds to flowalterations in a Mediterranean stream

Questions: Do Mediterranean riparian guilds show distinct responses to stream water declines? If observed,which are the most sensitive and resilient guilds and theirmost affected attributes? Location: Tie¿tar river below the Rosarito dam, central-western Spain. Methods: We identified riparian guilds based on key woody species features and species distribution within this Mediterranean river corridor, and evaluated similarity of their responses to long-term flow alteration (i.e. stream water declines since dam construction in 1959). Hierarchical cluster analysis was used to group surveyed vegetation bands according to species composition. The groups were designated as riparian guilds where each vegetation group comprising a guild: (1) contains species sharing similar features (using PCA); and (2) shares a similar environment (using DCA). Changes in several guild attributes (i.e. dominance and species composition, diversity and establishment patterns) during the regulated period were compared statistically. We used pre- and post-dam established vegetation bands identified based on old (1956) and modern (2006) aerial photographs and field measurements of woody species diameter. Results: Responses to flow alterations varied between guilds according to ecological requirements of their species. The ability to survive water stress (i.e. ?Xeric? guilds) and drag forces caused by floods (?Torrential? guilds) allowed certain pioneer shrub-dominated guilds (e.g. Flueggea tinctoria and Salix salviifolia) to spread on newly emerged surfaces downward to the main channel after flow alterations, although new shrubland had less species diversity than pre-dam shrubland. In contrast, new hydromorphological conditions following damming limited recruitment of native late-successional tree guilds sensitive to floods (to drag forces, inundation and anoxia; i.e. ?Slow-water? and ?Flood-sensitive?, respectively) and those with greater water requirements (i.e. ?Hydric?) (e.g. Alnus glutinosa and Celtis australis), although species diversity increased in this mature forest through co-existence of remaining riparian species and new arrival of upland species. Conclusions: Changes in several riparian attributes after flow alterations differed between guilds. Stream water declines after damming caused shifts in species-poor pioneer shrubland downwards to the watered channel, resulting in severe declines ofmaturenative forest.Understanding vegetation guild responses provides information about general trends in plant populations and assemblage structures expected to occur during river development and flow regulation, increasing our capacity to detect and synthesize complex flowalteration?riparian ecosystem response relationships, and anticipate irreversible impacts.

Nagele, a green building without a roof

The paper shows the design process of Nagele, a Dutch modernist agrarian settlement designed during the Post-Second World War period by the internationally recognized group of architects De 8 en Opbouw: Rietveld, Van Eesteren, Merkelbach, van Eyck, Bakema, Stam, Ruys, etc. It is located in the Noordoostpolder (NOP), in the Flevoland province, which was entirely reclaimed from the sea. The country planning of the Noodoostpolder reveals a high rationalization in the disposal of roads, canals, cities, agrarian land and forests, which can be an inspiration for the cities of today. The configurational elements of Nagele must be understood in terms of their relationship to the overall system of the polder. Important territorial principles in structure, form and landscape can be seen in the project of Nagele. This relationship is an additional example of the continuing transformation that the entire length and breadth of The Netherlands in subjected to. The research developed to date reveals a plan which shows the evolution of functionalistic paradigm at the CIAM postwar congresses. The particular case of Nagele points to the incorporation of human scale, green design and social co-existence. The source of these theories mainly came from Aldo van Eyck, who played an important role during the second phase of design. The research will be developed analyzing his drawings and texts and will show the way his theories appear in the project. Can Nagele be a materialization of Van Eyck¿s ideas? Nagele constitutes one of the most outstanding contributions to modern urban planning as far as both urbanism and landscape, are at the service of human well-being. Not only were urban independently designed parts, but their relationships also formed a perfect urban whole.

La construcción de la transparencia : Museo de Arte Contemporáneo del siglo 21 de Kanazawa - SANAA

La tesis doctoral “La construcción de la transparencia. Museo de Arte Contemporáneo del Siglo 21 de Kanazawa / SANAA” estudia, desde diferentes perspectivas, esta obra de los arquitectos japoneses Kazuyo Sejima + Ryue Nishizawa / SANAA. El museo, proyectado y construido entre 1999 y 2004, supone un referente arquitectónico de gran relevancia en el cambio de siglo, y está considerado un manifiesto construido en el que resuenan ecos culturales y sociales de su época. La investigación toma como constante el Museo del Siglo 21 de Kanazawa y a través de él se realizan una serie de miradas transversales a modo de narrativas interconectadas. Estas visiones múltiples colaboran, a través de las relaciones que se producen entre ellas, a generar un entendimiento global de esta obra y sus efectos sobre la cultura arquitectónica contemporánea. La tesis se estructura en dos partes: la primera estudia de manera analítica la obra en su contexto cultural, el proceso de proyecto y el edificio construido. La segunda parte propone una triple lectura interpretativa del edificio en relación a temas de especial relevancia para el proyecto y al modelo de espacio que constituye, tomando de nuevo como constante la noción de transparencia. La tesis partirá de la interpretación que hace del museo su directora artística Yuko Hasegawa, cuya colaboración activa durante el proceso de diseño resultó de gran relevancia para el resultado final. Hasegawa define la obra como la materialización de una situación cultural característica del nuevo siglo basada en tres conceptos: La Coexistencia, la Consciencia y la Inteligencia Colectiva. A partir de dichas ideas entenderemos la transparencia no sólo desde el punto de vista de las cualidades físicas y materiales del espacio sino también, desde una perspectiva más amplia: como estrategia utilizada para clarificar la organización funcional del edificio y las relaciones entre sus partes como posición política, catalizadora del espacio público; la producción de consciencia a través de la experiencia del arte y la arquitectura; y como medio de representación y generación de una identidad colectiva basada en la visibilidad mediática. Las conclusiones de esta investigación, extraídas de las confluencias y puntos de intersección de las diferentes miradas transversales proyectadas sobre la obra, determinan una clara voluntad por parte de los arquitectos de construir un espacio donde lo público se entiende como el ensamblaje de diferentes individualidades. De manera similar al proceso de proyecto, la multiplicidad y las relaciones entre elementos autónomos generan un consciencia colectiva del espacio donde, a través de la organización programática, la construcción y el uso de los materiales y la luz, la arquitectura tiene la voluntad de desvanecerse para ofrecer protagonismo a sus usuarios y a las relaciones y encuentros que se producen entre ellos y con el espacio que habitan. ABSTRACT The PhD thesis “The construction of transparency. 21st Century Museum of Contemporary Art in Kanazawa / SANAA” studies, from different perspectives, this work, realized by Japanese architects Kazuyo Sejima + Ryue Nishizawa / SANAA. The museum, designed and built between 1999 and 2004, had a huge relevance as an architectural referent in the swift of the century, being considered a built manifesto that echoes the culture and society of its time. The research takes as a constant the 21st Century Museum in Kanazawa and it is studied throughout a series of transversal readings as interconnected narratives. These multiple approaches and the relations among them, help to generate a global understanding of the building and its effects on contemporary architectural culture. The dissertation is structured in two parts: the first one studies from an analytical perspective the project in its cultural context, the process of design and the built work. The second part proposes a triple interpretative reading of the building in relation to topics that are especially relevant for the project and the spatial model that it constitutes, taking again the notion of transparency as a constant concept. The thesis departs from the interpretation expressed by the artistic director of the museum, Yuko Hasegawa, whose active collaboration during the design process had special relevance for the final result. She defines the work as the materialization of the cultural context of the new century based in three concepts: Co-existence, Consciousness and Collective Intelligence. From these concepts we will understand transparency, not only from the point of view of the physical and material qualities of the space, but also from a broader perspective: as an strategy used to clarify the functional organization of the building and the relation of its parts as political stand that catalyzes the public space; the production of consciousness based on the experience of art and architecture; and as a method of representation and construction of a collective identity based in the media visibility. The conclusions of this research -extracted from the confluences and intersections of the different transversal readings projected on the work- determine a clear intention by the architects to build a space where the public is understood as an assembly of different individualities. In a similar way as it happens in the design process, the multiplicity of relations between autonomous elements generate a collective consciousness of the space. Throughout the programmatic organization, the construction and the use of light and materials, the architecture has the will of disappearance to yield protagonist the users and the relations and encounters that happen among them and the space they inhabit.

Agrupaciones heterogéneas e intervención en arquitecturas existentes

Esta tesis doctoral profundiza, dentro del campo de la práctica del proyecto arquitectónico, en aquellas técnicas proyectuales que al intervenir sobre lo ya construido son capaces de cambiar su valor y su significado. La investigación tiene como objetivo demostrar que es posible revertir la obsolescencia de las arquitecturas ordinaras existentes mediante una técnica proyectual que hemos llamado agrupaciones heterogéneas. En ellas, la preexistencia y lo aportado inauguran un tiempo de convivencia que obliga a reinterpretar a la primera mientras que la segunda es forzada a traducir sus imaginarios. Esta investigación se conecta con el mundo del conocimiento a través de dos vectores, uno que lo enlaza con el estudio de las agrupaciones heterogéneas y otro con la intervención sobre arquitecturas ordinarias. Para el desarrollo de los trabajos, en una primera parte, se ha procedido al análisis de cada campo por separado a través del estudio de casos concretos: la plastic furniture de Charles y Ray Eames para el caso de las agrupaciones heterogéneas y el libro-manifiesto Plus de Frédéric Druot, Anne Lacaton y Jean-Philippe Vassal para la intervención sobre arquitecturas ordinarias. En cada estudio hemos obtenido unas conclusiones parciales: la arquitectura entendida como estado de encuentro y la teoría de la resistencia a los imaginarios. La segunda parte de la tesis toma el proyecto de Frank Gehry para su casa en Santa Mónica como un ejemplo en el que se ha revertido con éxito la obsolescencia de una arquitectura ordinaria a través de la técnica de las agrupaciones heterogéneas. A partir de ese ejemplo, y bajo la perspectiva de los dos campos estudiados, se propone una cartografía teórica para leer los procesos de innovación que tienen lugar al utilizar esta estrategia en diseño del proyecto. ABSTRACT This PhD thesis will provide an in-depth view of the techniques in practice in architectural projects, with proposals that are able to change the value and meaning of work that has already been built. The research is aimed at proving that it is possible to revert the obsolescence of the existing ordinary architecture using a project technique that we have called “heterogeneous ensembles”. In these ensembles, what existed beforehand and what has been contributed afterwards have brought about a new form of co-existence which forces the former to be reinterpreted and the latter to clarify its archetypes. This research connects to the world of knowledge through two vectors: one which links it to the study of the heterogeneous ensembles and the other to the work carried out on the ordinary architecture. To carry out this work, firstly we analysed each field separately by studying specific cases: the Charles and Ray Eames plastic furniture for the heterogeneous ensembles and the book and manifesto Plus by Frédéric Druot, Anne Lacaton and Jean- Philippe Vassal for the work carried out on the ordinary architecture. We drew partial conclusions in each study: architecture understood as a state of encounter and the theory of resistance to the archetypes. The second part of the thesis takes Frank Gehry’s project for his Santa Monica house as an example in which the obsolescence of ordinary architecture has been successfully reverted using the heterogeneous ensembles technique. Based on this example and from the standpoint of the two fields in question, we propose a theoretical cartography to read the innovation processes that take place when using this strategy in project design.

Influence of the molecular architecture on the secondary relaxations of Poly(styrene-co-methylmethacrylate) copolymers

The processes of adsorption of grafted copolymers onto negatively charged surfaces were studied using a dissipative quartz crystal microbalance (D-QCM) and ellipsometry. The control parameters in the study of the adsorption are the existence or absence on the molecular architecture of grafted polyethyleneglycol (PEG) chains with different lengths and the chemical nature of the main chain, poly(allylamine) (PAH) or poly(L-lysine) (PLL). It was found out that the adsorption kinetics of the polymers showed a complex behavior. The total adsorbed amount depends on the architecture of the polymer chains (length of the PEG chains), on the polymer concentration and on the chemical nature of the main chain. The comparison of the thicknesses of the adsorbed layers obtained from D-QCM and from ellipsometry allowed calculation of the water content of the layers that is intimately related to the grafting length. The analysis of D-QCM results also provides information about the shear modulus of the layers, whose values have been found to be typical of a rubber-like polymer system. It is shown that the adsorption of polymers with a charged backbone is not driven exclusively by the electrostatic interactions, but the entropic contributions as a result of the trapping of water in the layer structure are of fundamental importance.