Evolutionary ecology of host-symbiont interactions

Imperial Users onl

Long Term Evolution of the Size Distribution of Portuguese Cities

In this paper we study the evolution of the Portuguese urban system from 1864 to 2001. We apply the rank-size model and use rank-size estimates to describe the evolution of city-size hierarchy. Non paretian behaviour of the distribution is examined by adding a quadratic term to the basic equation of the model. Our results enhance two different processes in the evolution of urban system: until the middle of the twentieth century urban growth was accompanied by population concentration in the largest cities and proliferation of small cities; afterwards growth benefits middle size cities, reinforced in the last decades by heavy population losses in the two largest cities. From the association between the characteristics and evolving pattern of city size distribution and the spatial pattern of urban growth, it appears that the non paretian behaviour of city size distribution in the last decades can be linked to the particular growth process of cities located in the proximity of the central cities of the two metropolitan areas of Portugal’s mainland. In order to obtain a better understanding of the dynamics of the Portuguese urban system we examine the movements in the ranking of cities. We also analyse the existence of spatial correlation in the process of urban hierarchy restructuring.

The evolution of city size distribution in Portugal: 1864-2001

The rank-size model - which states that the size distribution of cities in a country follows a Pareto distribution - has been recognized as one of those stylised facts or amazing empirical regularities, in spatial economics. A common problem in city size distribution studies concerns the definition of “cities”, namely the consistency of those definitions over time. In this paper we use a city-proper data base which uses a consistent definition of cities from 1864 to 1991. Portugal is a country with long established national borders and whose mainland urban system shows a constant number of cities over that period. In Portugal, empirical evidence on city size distribution based on census data shows that two large cities dominate the urban system, associated with a large number of very small cities and a clear deficit of medium-size cities. In this paper we analyse the evolution of the rank size exponent and examine the effect of varying city size cut-offs on the estimated value of that exponent. Then, we study the deviations of the rank-size distribution from linearity. Finally, we explore the dynamics underlying the evolution of the urban system by examining the relationship between city growth rates and city size. Keywords: city size distribution, Zipf’s law, rank-size, urban hierarchy, urban primacy

The evolution of city size distribution in Portugal: 1864-2001

The rank-size model - which states that the size distribution of cities in a country follows a Pareto distribution - has been recognized as one of those stylized facts or amazing empirical regularities, in spatial economics. A common problem in city size distribution studies concerns the definition of “cities”, namely the consistency of those definitions over time. In this paper we use a city-proper data base which uses a consistent definition of cities from 1864 to 1991. Portugal is a country with long established national borders and whose mainland urban system shows a constant number of cities over that period. In Portugal, empirical evidence on city size distribution based on census data shows that two large cities dominate the urban system, associated with a large number of very small cities and a clear deficit of medium-size cities. In this paper we analyse the evolution of the rank size exponent and examine the effect of varying city size cut-offs on the estimate value of that exponent. Then, we study the deviations of the rank-size distribution from linearity. Finally, we explore the dynamics underlying the evolution of the urban system by examining the relationship between city growth rates and city size.city size distribution, Zipf’s law, urban hierarchy, urban primacy

Long term evolution of the size distribution of Portuguese cities

In this paper we study the evolution of the Portuguese urban system from 1864 to 2001. We apply the rank-size model and use rank-size estimates to describe the evolution of city-size hierarchy. NonParetian behavior of the distribution is examined by adding a quadratic term to the basic equation of the model. Our results enhance two different processes in the evolution of urban system: until the middle of the twentieth century urban growth was accompanied by population concentration in the largest cities; afterwards growth benefits middle size cities, reinforced in the last decades by heavy population losses in the two largest cities. From the association between the characteristics and evolving pattern of city size distribution and the spatial pattern of urban growth, it appears that the nonParetian behavior of city size distribution in the last decades can be linked to the particular growth process of cities located in the proximity of the central cities of the two metropolitan areas of mainland Portugal. In order to obtain a better understanding of the dynamics of the Portuguese urban system we examine the movements in the ranking of cities, through a Markov chain process. We also analyse the existence of spatial correlation in the process of urban hierarchy restructuring.Urban hierarchy, rank-size distribution, urban growth, Markov processes

Antibacterial scaffolds constituted by trilayers of microfibers based on polylactide and poly (3-hydroxybutyrate-co-3-hydroxyvalerate)

L’objectiu d’aquest treball final de màster va ser la fabricació de fibres poroses uniaxials i amb tricapa que presentésfuncions antibacterianesi potencialment d’altresfuncionalitats (antitumoral, antioxidant, antibaterial...). Les fibres es van fabricar mitjançant la tècnica de l’electrospinning a partir d’una dissolució de polímers i sempre treballant amb un polímer comercial, el PHB. El disseny de les matrius va consistir en una capa de mescla PLA/PEG als extrems i PHBV al mig, amb configuració similar a un tipus sandvitx. La droga antibacterial es va incorporar també a la capa intermitja, mesclada amb el PHBV. A més, van afegir també partícules d’hidroxiapatita per formar complexes Matriu-Hidroxiapatita i així poder estudiar la alliberació de droga. Per tal d’obtenir les matrius amb les condicions òptimes, es van modificar els paràmetres durant l’electrospinning de fibres amb una sola capa i es van provar diferents concentracions i diferents dissolvents. Un cop obtinguts els valors òptims dels paràmetres i el dissolvent adequat, es va procedir a crear diferent matrius amb diferents característiques i components per el seu posterior estudi. En el desenvolupament del projecte es van dur a terme diferents caracteritzacions, tant físiques com químiques de les matrius creades. Primer es va estudiar els angles de contacte, en funció del comportament de l’aigua al estar en contacte amb la superfície de les matrius. Tots els resultats obtinguts van ser superiors a 120º per tant, es va considerar el polímer estudiat era de tipus hidrofòbic, ja que presentava valors superiors al 90º. Posteriorment, es van analitzar els diàmetres de les fibres que s’obtenien a les matrius mitjançant microscòpia electrònica de rastreig (SEM) i també es va obtenir l’espectre de cadascuna dels components que es van utilitzar per muntar les matrius (per espectroscòpia infraroig) per tal d’obtenir les absorcions dels components que formaven part d’elles. Per últim es va realitzar un estudi de l’alliberació de la droga, dissolent una mostra de les matrius que contenien la droga (per triplicat) amb un medi utilitzat per creixement biològic (PBS). L’estudi es va realitzar en un temps total de 48h, realitzant mostreigs periòdics i finalment, analitzant les absorbàncies obtingudes mitjançant l’espectrometria UV-Vis per obtenir concentracions finals i amb les seves regressions, obtenir dades sobre l’alliberació en el temps de la droga. El treball realitzat al laboratori inclou el muntatge experimental, la preparació de les dissolucions de polímers per dur a terme cadascuna de les tècniquesi la realització dels experiments mitjançant cadascuna de les tècniques mencionades. Finalment, a partir de les diferents proves realitzades es va poder determinar la naturalesa del polímer emprat, la seva morfologia, el seu comportament químic així com la capacitat d’alliberament de droga que presenta vers el temps.El objetivo de este trabajo final de máster fue la fabricación de fibras porosas uniaxiales y con tricapa que presentase funciones antibacterianas y potencialmente otras funcionalidades (antitumoral, antioxidante, antibacterianas...). Las fibras se fabricaron mediante la técnica de la electrospinning a partir de una disolución de polímeros y siempre trabajando con un polímero comercial, el PHB. El diseño de las matrices consistió en una capa de mezcla PLA/PEG en los extremos y PHBV en medio, con configuración similar a un tipo sándwich. La droga antibacteriana se incorporó también a la capa intermedia, mezclada con el PHBV. Además, se añadieron también partículas de hidroxiapatita para formar complejos Matriz-Hidroxiapatita y así poder estudiar la liberación de droga. Para obtener las matrices con las condiciones óptimas, se modificaron los parámetros durante el electrospinning de fibras con una sola capa y se probaron diferentes concentraciones y diferentes disolventes. Una vez obtenidos los valores óptimos de los parámetros y el disolvente adecuado, se procedió a crear diferentes matrices con diferentes características y componentes para su posterior estudio. En el desarrollo del proyecto se llevaron a cabo diferentes caracterizaciones, tanto físicas como químicas de las matrices creadas. Primero se estudió los ángulos de contacto, en función del comportamiento del agua al estar en contacto con la superficie de las matrices. Todos los resultados obtenidos fueron superiores a 120° por lo tanto, se consideró que el polímero estudiado era de tipo hidrofóbico, puesto que presentaba valores superiores al 90°. Posteriormente, se analizaron los diámetros de las fibras que se obtenían mediante microscopia electrónica de rastreo (SEM) y también se obtuvo el espectro de cada uno de los componentes que se utilizaron para montar las matrices (por espectroscopia infrarrojo) para obtener las absorciones de los componentes que formaban parte de ellas. Por último, se realizó un estudio de la liberación de la droga, disolviendo una muestra de las matrices que contenían la droga (por triplicado) con un medio utilizado para crecimiento biológico (PBS). El estudio se realizó durante un tiempo total de 48h, realizando muestreos periódicos y finalmente, analizando las absorbancias obtenidas mediante la espectrometría UV-Vis, para obtener concentraciones finales y con susregresiones, obtener datos sobre la liberación de la droga en el tiempo. El trabajo realizado en el laboratorio incluye el montaje experimental, la preparación de las disoluciones de polímeros para llevar a cabo cada una de las técnicas y la realización de los experimentos mediante cada una de las técnicas mencionadas. Finalmente, a partir de las diferentes pruebas realizadas se pudo determinar la naturaleza del polímero empleado, su morfología, su comportamiento químico, así como la capacidad de liberación de droga presentaba respecto al tiempo.The objective of this final master thesis was the fabrication of porous uniaxial trilayer fibers that present antibacterial functions and other potential functionalities (antitumoral, antioxidant, antibacterial...). Fibers were made by means of electrospinning technique, from a polymer solution and aways working with a commercial polymer type, PHB. Scaffolds design consists of a mixture PLA/PEG applied in a layer on extremes and PHBV at the middle, with a sandwich seems configuration. Antibacterial drug was added to intermediate layer, mixed with PHBV. Additionally, it was added particles of hydroxyapatite to form Scaffold-Hydroxyapatite complexes and allow to study drug liberation. To obtain scaffolds in optimum conditions, it was modified the parameters during electrospinning process with unilayer scaffolds and there were tested different concentrations and solvents. Once optimal parameters were obtained and the suitable solvent, different scaffolds were created with different characteristics and components for its posterior study. During the development of the project, different physical and chemical characterizations were made on the created polymer scaffolds. Firstly, contact angle of the scaffolds was evaluated in function of water behavior been in contact with surface scaffold. All angles obtained were higher than 120º and, for so, it was considered that the polymer analyzed was hydrophobic, as it has values higher than 90º. Subsequently, it was analyzed the diameters of fibers by means ofscanning electron microscopy (SEM) and spectra were obtained for each of the components that were used to make the scaffolds (by FTIR spectroscopy) and obtain the absorbances of the components that be part of them. Finally, it was made a liberation of the drug study, dissolving a sample of the scaffold that contains the drug per triplicated, with a biological grown media (PBS). The study was done during a total time of 48h, making periodical samplings and, finally, analyzing obtained absorbances by means of UV-Vis spectroscopy, to obtain the final concentrations and its regressions, obtaining data about drug release pending time. The laboratory tasks made, include experimental setup, preparation of polymer solutions to carry out each of the techniques and the perform of the experiments by means of all the mentioned techniques. Finally, from the different tests performed, it was possible to stablish the nature of the polymer used, its morphology, chemical behavior, and its capacity to drug release in time

Diseño del proceso de elaboración

El presente trabajo trata sobre el diseño del proceso para la elaboración de un subproducto que permita diversificar la producción de banano deshidratado, cumpliendo con los estándares de calidad exigidos. Para ello se aprovecharon los desperdicios propios de la línea, con el fin de obtener un producto uniforme, de calidad y precio competitivo. Se propusieron diferentes productos para ser desarrollados, y se eligió aquel se adaptaba de una mejor manera a los requerimientos establecidos. Luego de elegir las materias primas adecuadas, se diseñó el proceso de elaboración del producto y se establecieron métodos para el control del peso por unidad. Por otro lado, se determinaron los parámetros físicos, tales como peso y tamaño por unidad, y se establecieron las características organolépticas, microbiológicas y nutricionales del producto. Finalmente, se determinó la vida útil del producto obtenido a diferentes temperaturas

"Pan precocido suave con especies"

During the past years, people’s life styles have been changing due to the new trends adopted around the world. Nowadays, people live faster and dedicated more time to work and the families are smaller. The Ecuadorians are adopting this XXI lifestyle and this provokes the consuming habits change, and in a specific way the feeding habits. The traditional elaboration of meals in the kitchen that requires of long time and dedication has left behind. For that reason, food markets require of nutritious products of quick preparation and ready to be consumed. The present Project consist in the development of a product designed for a market as the one mentioned before, in which details its technical development, formulation, manufacturing, sensing test and quality control . The project also includes the market research realized before the development of the product. The marketplace is focused in Quito’s high class institutional market. In addition, the financial study and the legal aspect are also shown in this project.Durante los últimos años la forma de vida de las personas ha ido cambiando debido a las nuevas tendencias que se adoptan en el mundo. Hoy en día se vive más rápido y cada vez se le dedica más tiempo al trabajo; además las familias son cada vez más pequeñas. Los ecuatorianos poco a poco van adoptando este tipo de vida del siglo XXI y esto provoca que los hábitos de consumo vayan cambiando, y el consumo de los alimentos específicamente. La elaboración tradicional de los alimentos en la cocina, que requiere de largos tiempos y dedicación, ha ido quedando atrás. Por lo tanto los nuevos mercados requieren de productos alimenticios de fácil y rápida preparación y que estén listos para consumir. El presente proyecto consiste en el desarrollo de un producto diseñado para un mercado como el mencionado, en el cual se detalla su desarrollo técnico: formulación, manufactura, pruebas sensoriales y control de calidad. El proyecto también incluye el estudio de mercado realizado previo al desarrollo del producto, que se enfoca en el mercado institucional de clase alta de la ciudad de Quito. Además se incluye un estudio financiero y los aspectos legales que envuelven el desarrollo del proyecto

Música e inspiração em The Lady Vanishes de Alfred Hitchcock

Tendo como base The Lady Vanishes (1938), o presente ensaio trata o conceito de conspiração no filme em causa e noutros do mesmo realizador, relacionando-o com a importância também da música em Alfred Hitchcock, ao mesmo tempo que se demonstra o carácter revolucionário da sua obra. No thriller, enquanto género inaugurado por Hitchcock, a conspiração figura como um pano de fundo da intriga que não chega, afinal, a ser nada em concreto. A música deixa de ser apenas coadjuvante das imagens para, refletindo sobre elas, deter um papel decisivo nos filmes deste cineasta. As técnicas da conspiração no plano estético são ainda comparadas às do plano sociológico, aqui ilustradas pelas técnicas efetivas da ideologia do Nacional Socialismo, de alguma forma perscrutadas por Hitchcock já em 1938.Based on The Lady Vanishes (1938), this paper covers the concept of conspiracy in that movie and in others of the same director, comparing it with the importance of music in Alfred Hitchcock and showing at the same time the revolutionary features of his work. In the thriller, film genre initiated by Hitchcock, conspiracy figures as a background of the plot, but it isn’t, actually, nothing in concrete. Music is no longer a mere support for images but it reflects about them, playing a crucial role in this filmmaker’s movies. The conspiracy techniques in the aesthetic field are also compared with the effective techniques in the sociologic field, here illustrated by the National Socialism’s ideology, which techniques were somehow foreseen by Hitchcock in 1938.info:eu-repo/semantics/publishedVersio

Aragons "La Mise à mort" und die Rezeption romantischer Motive

"La Mise à mort" gehört der dritten Schaffensperiode Louis Aragons an. Sie folgt der surrealistischen Phase und der "wirklichen Welt"- Periode nach. Dieser Roman aus dem Jahr 1965 ist die Bilanz seines bisherigen Werkes. Aragon konzentriert sich auf Probleme seines Schaffens und entwirft eine Synthese seiner eigenen Entwicklung in fiktiver Gestalt. Er greift dabei auf die Hegelsche Dialektik zurück, die er in seiner Jugend intensiv studiert hat. Die Widersprüchlichkeit seiner Entwicklung stellt er in La Mise à mort durch die Doppelgänger Alfred (der Erzähler des Romans) und Anthoine (Autor der "Drei Erzählungen aus der roten Mappe"), und auch Christian, einen dritten Doppelgänger, dar. Das Grundthema des Romans ist die Suche nach der Wahrheit auf drei Ebenen: Nach der historischen Wahrheit in "Murmure", nach der Wahrheit des einzelnen Menschen in "Le Carnaval" und nach der Wahrheit in der Kunst in "Oedipe". Die drei Erzählungen aus der roten Mappe bringen die Vergangenheit Aragons ans Licht. Die Wiederentdeckung der surrealistischen Vergangenheit ist die Hauptantriebskraft für das Schreiben der drei Erzählungen. Das surrealistische Erbe muss dabei im Kontext der Romantik-Rezeption betrachtet werden (vor allem der deutschen Romantik). Von besonderer Brisanz für die Realismusdiskussion in La Mise à mort ist die Rezeption der im Roman behandelten romantischen Motive des Spiegels, des Schattens und des Doppelgängers. Sie tragen zu einer Öffnung des sozialistischen Realismusbegriffs bei, indem sie Werte der Phantasie und der Subjektivität darstellen und damit die Freiheit in der Wahl der Gestaltungsmethode erweitern."La Mise à mort" belongs to the third phase of Louis Aragon's literary creation after the Surrealist period and the "Monde réel" phase; this 1965 novel appears as a balance of his work. Aragon concentrates on the problems of his creative work and sketches a synthesis of its evolution in fictional form using the philosophical method that he had studied in his youth and applied in his early writings: the Hegelian dialectic. It is through the personae of Alfred, narrator of the novel, Anthoine, author of the "Trois contes de la chemise rouge", and also Christian, that he presents the contradictions of this evolution. The main theme chosen for this presentation is the search for truth, trying to show the complexity of the various aspects of reality: the search for historical truth in "Murmure"; the search for individual truth in "Le Carnaval"; and the search for truth in art in "Oedipe". The rediscovery of the surrealist past is the main driving force behind the writing of the three stories, and the surrealist heritage appears in the context of the reception of Romanticism, especially German Romanticism. Particularly important for the reception of German Romanticism will be the three motifs of the mirror, the shadow, and the double (Doppelgänger), illustrating a broad conception of socialist realism at this stage, distancing itself from dogmatic conceptions of realism and extending the concept to values of fantasy and subjectivity