888 resultados para A revolution of their own


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After a criticism on today’s model for electrical noise in resistors, we pass to use a Quantum-compliant model based on the discreteness of electrical charge in a complex Admittance. From this new model we show that carrier drift viewed as charged particle motion in response to an electric field is unlike to occur in bulk regions of Solid-State devices where carriers react as dipoles against this field. The absence of the shot noise that charges drifting in resistors should produce and the evolution of the Phase Noise with the active power existing in the resonators of L-C oscillators, are two effects added in proof for this conduction model without carrier drift where the resistance of any two-terminal device becomes discrete and has a minimum value per carrier that is the Quantum resistance RK/(2pi)

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The latest technology and architectural trends have significantly improved the use of a large variety of glass products in construction which, in function of their own characteristocs, allow to design and calculate structural glass elements under safety conditions. This paper presents the evaluation and analysis of the damping properties of rectangular laminated glass plates of 1.938 m x 0.876 m with different thickness depending on the number of PVB interlayers arranged. By means of numerical simulation and experimental verification, using modal analysis, natural frequencies and damping of the glass plates were calculated, both under free boundary conditions and operational conditions for the impact test equipment used in the experimental program, as the European standard UNE-EN 12600:2003 specifies.

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Performance of football teams varies constantly due to the dynamic nature of this sport, whilst the typical performance and its spread can be represented by profiles combining different performance-related variables based on data from multiple matches. The current study aims to use a profiling technique to evaluate and compare match performance of football teams in the UEFA Champions League incorporating three situational variables (i.e. strength of team and opponent, match outcome and match location). Match statistics of 72 teams, 496 games across four seasons (2008-09 to 2012-13) of this competition were analysed. Sixteen performance-related events were included: shots, shots on target, shots from open play, shots from set piece, shots from counter attack, passes, pass accuracy (%), crosses, through balls, corners, dribbles, possession, aerial success (%), fouls, tackles, and yellow cards. Teams were classified into three levels of strength by a k-cluster analysis. Profiles of overall performance and profiles incorporating three situational variables for teams of all three levels of strength were set up by presenting the mean, standard deviation, median, lower and upper quartiles of the counts of each event to represent their typical performances and spreads. Means were compared by using one-way ANOVA and independent sample t test (for match location, home and away differences), and were plotted into the same radar charts after unifying all the event counts by standardised score. Established profiles can present straightforwardly typical performances of football teams of different levels playing in different situations, which could provide detailed references for coaches and analysts to evaluate performances of upcoming opposition and of their own.

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Passive performance of buildings is nowadays one of the key points, not only for reducing energy consumption of buildings, but also for decreasing “fuel poverty”. Among the constructive systems in buildings, façades are the ones having higher influence on thermal performance in urban spaces. Lime renders are specialized systems which can improve not only the durability of the support but also the thermal properties. According to previous researches, a modification of their radiative properties can reduce thermal fluxes between 24% and 89%. In this paper, the influences of the aggregate content in lime pastes, as well as the nature of the aggregates, colour and roughness, on the visible near and medium infrared reflectance are analyzed. Ten types of aerial lime mortars were prepared and two methods of reflectance determination were performed. Finally, the effect of the resulted reflectance on the constructive systems of façades was analyzed using pseudotime-dependent software, for which an annulation of the thermal fluxes or significant reduction of them can be observed, when modifying the aggregate nature.

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Las poblaciones de salmónidos en la Península Ibérica (trucha común, Salmo trutta; y salmón atlántico, Salmo salar) se encuentran cerca del límite meridional de sus distribuciones naturales, y por tanto tienen una gran importancia para la conservación de estas especies. En la presente Tesis se han investigado algunos aspectos de la reproducción y de la gestión del hábitat, con el objeto de mejorar el conocimiento acerca de estas poblaciones meridionales de salmónidos. Se ha estudiado la reproducción de la trucha común en el río Castril (Andalucía, sur de España), donde se ha observado que la freza ocurre desde diciembre hasta abril con el máximo de actividad en febrero. Este hecho representa uno de los periodos reproductivos más tardíos y con mayor duración de toda la distribución natural de la especie. Además, actualmente se sabe que el resto de poblaciones andaluzas tienen periodos de reproducción similares (retrasados y extendidos). Análisis en la escala de la distribución natural de la trucha común, han mostrado que la latitud explica parcialmente tanto la fecha media de reproducción (R2 = 62.8%) como la duración del periodo de freza (R2 = 24.4%) mediante relaciones negativas: a menor latitud, la freza ocurre más tarde y durante más tiempo. Es verosímil que un periodo de freza largo suponga una ventaja para la supervivencia de las poblaciones de trucha en hábitats impredecibles, y por tanto se ha propuesto la siguiente hipótesis, que deberá ser comprobada en el futuro: la duración de la freza es mayor en hábitats impredecibles que en aquellos más predecibles. La elevada tasa de solapamiento de frezaderos observada en el río Castril no se explica únicamente por una excesiva densidad de reproductores. Las hembras de trucha eligieron lugares específicos para construir sus frezaderos en vez de dispersarse aleatoriamente dentro del hábitat adecuado para la freza que tenían disponible. Estas observaciones sugieren que las hembras tienen algún tipo de preferencia por solapar sus frezaderos. Además, en ríos calizos como el Castril, las gravas pueden ser muy cohesivas y difíciles de excavar, por lo que el solapamiento de frezaderos puede suponer una ventaja para la hembra, porque la excavación en sustratos que han sido previamente removidos por frezas anteriores requerirá menos gasto de energía que en sustratos con gravas cohesivas que no han sido alteradas. Por tanto, se ha propuesto la siguiente hipótesis, que deberá ser comprobada en el futuro: las hembras tienen una mayor preferencia por solapar sus frezaderos en ríos con sustratos cohesivos que en ríos con sustratos de gravas sueltas. En el marco de la gestión del hábitat, se han empleado dos enfoques diferentes para la evaluación del hábitat físico, con el objeto de cuantificar los cambios potenciales en la disponibilidad de hábitat, antes de la implementación real de determinadas medidas sobre el hábitat. En primer lugar, se ha evaluado el hábitat físico del salmón atlántico en el río Pas (Cantabria, norte de España), en la escala del microhábitat, empleando la metodología IFIM junto con un modelo hidráulico bidimensional (River2D). Se han simulado una serie de acciones de mejora del hábitat y se han cuantificado los cambios en el hábitat bajo estas acciones. Los resultados mostraron un aumento muy pequeño en la disponibilidad de hábitat, por lo que no sería efectivo implementar estas acciones en este tramo fluvial. En segundo lugar, se ha evaluado el hábitat físico de la trucha común en el río Tajuña (Guadalajara, centro de España), en la escala del mesohábitat, empleando la metodología MesoHABSIM. Actualmente, el río Tajuña está alterado por los usos agrícolas de sus riberas, y por tanto se ha diseñado una restauración para mitigar estos impactos y para llevar al río a un estado más natural. Se ha cuantificado la disponibilidad de hábitat tras la restauración planteada, y los resultados han permitido identificar los tramos en los que la restauración resultaa más eficaz. ABSTRACT Salmonid populations in the Iberian Peninsula (brown trout, Salmo trutta; and Atlantic salmon, Salmo salar) are close to the southern limit of their natural ranges, and therefore they are of great importance for the conservation of the species. In the present dissertation, some aspects of spawning and habitat management have been investigated, in order to improve the knowledge on these southern salmonid populations. Brown trout spawning have been studied in the river Castril (Andalusia, southern Spain), and it has been observed that spawning occurs from December until April with the maximum activity in February. This finding represents one of the most belated and protracted spawning periods within the natural range of the species. Furthermore, it is now known that the rest of Andalusian populations show similar (belated and extended) spawning periods. Broad-scale analyses throughout the brown trout natural range showed that latitude partly explained both spawning mean time (R2 = 62.8%) and spawning duration (R2 = 24.4%) by negative relationships: the lower the latitude, the later the spawning time and the longer the spawning period. It is plausible that a long spawning period would be an advantage for survival of trout populations in unpredictable habitats, and thus the following hypothesis has been proposed, which is yet to be tested: spawning duration is longer in unpredictable than in predictable habitats. High rate of redd superimposition observed in the river Castril was not only caused by high density of spawners. Trout females chose specific sites for redd construction instead of randomly dispersing over the suitable spawning habitat. These observations suggest that female spawners have some kind of preference for superimposing redds. Moreover, in limestone streams such as Castril, unused gravels can be very cohesive and hard to dig, and thus redd superimposition may be an advantage for female, because digging may require less energy expenditure in already used redd sites than in cohesive and embedded unused sites. Hence, the following hypothesis has been proposed, which is yet to be tested: females have a higher preference for superimposing redds in streambeds with cohesive and embedded substrates than in rivers with loose gravels. Within the topic of habitat management, two different approaches have been used for physical habitat assessment, in order to quantify the potential change in habitat availability, prior to the actual implementation of proposed habitat measures. Firstly, physical habitat for Atlantic salmon in the river Pas (Cantabria, northern Spain) has been assessed at the microhabitat scale, using the IFIM approach along with a two dimensional hydraulic model (River2D). Proposed habitat enhancement actions have been simulated and potential habitat change has been quantified. Results showed a very small increasing in habitat availability and therefore it is not worth to implement these measures in this stream reach. Secondly, physical habitat for brown trout in the river Tajuña (Guadalajara, central Spain) has been assessed at the mesohabitat scale, using the MesoHABSIM approach. The river Tajuña is currently impacted by surrounding agricultural uses, and thus restoration was designed to mitigate these impacts and to drive the river to a more natural state. Habitat availability after the planned restoration has been quantified, and the results have permitted to identify in which sites the restoration will be more effective.

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La Casa Industrializada supone el ideal de realizar la casa unifamiliar a través de la potencia y los procedimientos de la industria. Como tal, la casa supone un producto industrial más sujeto a la lógica de la reproducción y del consumo. Como producto de consumo la casa debe establecerse como objeto de deseo, accesible al grupo de usuarios-consumidores al que va dirigido. El sueño de la Casa Industrializada se origina en la primera Revolución Industrial y se consolida en la segunda tras la producción del Ford T y la adhesión de los padres del movimiento moderno. A lo largo de su historia se han sucedido casos de éxito y fracaso, los primeros con la realización de un producto de imagen convencional y los segundos la mayor parte de las veces dirigidos por arquitectos. El sueño de la Casa Industrializada de la mano de arquitectos está comenzando a ser una realidad en Japón, Suecia y Estados Unidos a través de marcas como MUJI, Arkitekthus y Living Homes, pero aún dista de ser un hecho extendido en nuestra sociedad. Para que este ideal se cumpla deberá ofrecer valores que permita a la sociedad hacerlo suyo. La Tesis busca analizar la historia y la metodología de la Casa Industrializada, desde el diseño a la comercialización con el fin de ofrecer esos valores en forma de propuestas para la Casa Industrializada en este milenio. La casa como producto industrial-producto de consumo supera las lógicas tradicionales de la arquitectura para operar dentro del contexto de la producción industrial y la reproducción de los objetos. En este sentido es necesario establecer no solo la forma y construcción de la casa sino los mecanismos de reproducción con sus pertinentes eficiencias. La Casa industrializada no se construye, se monta, y para ello utiliza las estrategias de la construcción en seco, la prefabricación, el uso de componentes y los materiales ligeros. Desde la lógica del consumo, la casa debe dirigirse a un determinado público, no es más la casa para todos, característica de las situaciones de crisis y de emergencia. La casa se enfrenta a un mercado segmentado, tanto en cultura, como en deseos y poderes adquisitivos. En la cuestión del diseño debe plantearse más como diseño de producto que como diseño arquitectónico. La Casa Industrializada no es el fruto de un encargo y de una acción singular, debe ofrecerse lista para adquirir y para ser reproducida. Esta reproducción se puede dar tanto en la forma de modelos cerrados o sistemas abiertos que permitan la personalización por parte de los usuarios. Desde el ámbito cultural es necesario entender que la casa es más que una máquina de habitar, es un receptor de emociones, forma parte de nuestra memoria y nuestra cultura. La casa como producto social es una imagen de nosotros mismos, define la manera en la que nos situamos en el mundo y por tanto supone una definición de estatus. En esto, la Tesis se apoya en los textos de Baudrillard y su análisis de la sociedad de consumo y el papel de los objetos y su valor como signo. La Tesis realiza un repaso de los procedimientos industriales con especial énfasis en la producción automovilística y sitúa la evolución de la Casa Industrializada en relación a la evolución de los avances en los sistemas de producción industrial y las transferencias desde las industrias del automóvil y aeronáutica. La tesis se completa con una serie de casos de estudio que parten de las primeras casas de venta por correo de principios del siglo XX, pasando por las propuestas de Gropius, Fuller, el Case Study House Program, Prouvé, Sota y acaban con la situación actual. La Casa Industrializada ha mantenido una serie de valores a lo largo de su historia, como ideal, forma un cuerpo estable de propuestas que no se ha modificado a lo largo del tiempo. Con respecto a este nuevo milenio este ideal no debe ser cambiado sino simplemente actualizado y adaptado a los métodos de producción y las necesidades, sueños y exigencias de la sociedad de hoy. ABSTRACT The industrialized House provides an ideal to manufacture the house through the power and strategies of the industry. As such, the house becomes an industrial product that respond to the logic of reproduction and consumption. As a comodity, the house must become a desirable object, accessible to the group of the consumers to which is targeted The dream of the Industrialized home is originated in the First Industrial Revolution and it is consolidated in the second one after Ford´s production of Model T and the incorporation of the principal figures of the modern movement to the ideal of making houses at the factories. Throughout history there have been cases of success and failure, the first with the completion of a product of conventional image and the second most often led by architects. Industrialized dream house made by architects is starting to become a reality in Japan, Sweden and the United States through brands such as MUJI, Arkitekthus and Living Homes, but still far from beeing a widespread fact in our society. To fulfill this ideal, it should provide values that society could accept as of their own. The Thesis seeks to analyze the history and methodology of industrialized house, from design to marketing in order to offer these values in the form of proposals for industrialized house in this millennium. The house as an industrial-product-comodity extend beyond the traditional architectural logic to operate within the context of industrial production and the reproduction of objects. In this sense it is necessary to establish not only the shape and construction of the house but the mechanisms of reproduction with its relevant efficiencies. Industrialized house is not built it is assembled, and it uses the strategies of dry construction, prefabrication, using lightweight materials and components. From the logic of consumption, the house must go to a certain audience, it is no longer the home for all that is characteristic of crisis respond and emergency. The house faces a segmented market, both in culture and desires and purchasing power. On the question of design it must be considered more like product design than architectural design. Industrialized House is not the result of a commission and a singular action, it should be offered pret-a-porter and able to be reproduced. This reproduction can be given in form of closed or open systems models that allow its customization by users. From the cultural sphere is necessary to understand that the house is more than a machine for living, is a recipient of emotions, is part of our memory and our culture. The home as a social product is an image of ourselves, defines the way in which we place ourselves in the world and therefore represents a definition of status. In this aspect, the thesis is based on the texts of Baudrillard and his analysis of consumption society and the role of objects and its value as a sign in it. The thesis makes a review of the industrial processes with emphasis on automotive production and places the evolution of industrialized House in relation to the evolution of developments in industrial production systems and transfers from the automotive and aeronautics industries. The thesis is completed with a series of case studies that starts from the first mail order houses from the early twentieth century, going through the proposal of Gropius, Fuller, the Case Study House Program, Prouvé, Sota and end up with the current situation. Industrialized House has held a series of values throughout its history, as an ideal, forms a stable corps of proposals that has not changed over time. Regarding this new millennium this ideal should not be changed but simply be updated and adapted to production methods and needs, dreams and demands of today's society.

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Human hematopoiesis originates in a population of stem cells with transplantable lympho-myeloid reconstituting potential, but a method for quantitating such cells has not been available. We now describe a simple assay that meets this need. It is based on the ability of sublethally irradiated immunodeficient nonobese diabetic–scid/scid (NOD/SCID) mice to be engrafted by intravenously injected human hematopoietic cells and uses limiting dilution analysis to measure the frequency of human cells that produce both CD34−CD19+ (B-lymphoid) and CD34+ (myeloid) colony-forming cell progeny in the marrow of such recipients 6 to 8 weeks post-transplant. Human cord blood (CB) contains ≈5 of these competitive repopulating units (CRU) per ml that have a similar distribution between the CD38− and CD38+ subsets of CD34+ CB cells as long-term culture-initiating cells (LTC-IC) (4:1 vs. 2:1). Incubation of purified CD34+CD38− human CB cells in serum-free medium containing flt-3 ligand, Steel factor, interleukin 3, interleukin 6, and granulocyte colony-stimulating factor for 5–8 days resulted in a 100-fold expansion of colony-forming cells, a 4-fold expansion of LTC-IC, and a 2-fold (but significant, P < 0.02) increase in CRU. The culture-derived CRU, like the original CB CRU, generated pluripotent, erythroid, granulopoietic, megakaryopoietic, and pre-B cell progeny upon transplantation into NOD/SCID mice. These findings demonstrate an equivalent phenotypic heterogeneity amongst human CB cells detectable as CRU and LTC-IC. In addition, their similarly modest response to stimulation by a combination of cytokines that extensively amplify LTC-IC from normal adult marrow underscores the importance of ontogeny-dependent changes in human hematopoietic stem cell proliferation and self-renewal.

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In behavior reminiscent of the responsiveness of human infants to speech, young songbirds innately recognize and prefer to learn the songs of their own species. The acoustic and physiological bases for innate recognition were investigated in fledgling white-crowned sparrows lacking song experience. A behavioral test revealed that the complete conspecific song was not essential for innate recognition: songs composed of single white-crowned sparrow phrases and songs played in reverse elicited vocal responses as strongly as did normal song. In all cases, these responses surpassed those to other species’ songs. Although auditory neurons in the song nucleus HVc and the underlying neostriatum of fledglings did not prefer conspecific song over foreign song, some neurons responded strongly to particular phrase types characteristic of white-crowned sparrows and, thus, could contribute to innate song recognition.

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The evolutionary relationships of 46 Shigella strains representing each of the serotypes belonging to the four traditional Shigella species (subgroups), Dysenteriae, Flexneri, Boydii, and Sonnei, were determined by sequencing of eight housekeeping genes in four regions of the chromosome. Analysis revealed a very similar evolutionary pattern for each region. Three clusters of strains were identified, each including strains from different subgroups. Cluster 1 contains the majority of Boydii and Dysenteriae strains (B1–4, B6, B8, B10, B14, and B18; and D3–7, D9, and D11–13) plus Flexneri 6 and 6A. Cluster 2 contains seven Boydii strains (B5, B7, B9, B11, B15, B16, and B17) and Dysenteriae 2. Cluster 3 contains one Boydii strain (B12) and the Flexneri serotypes 1–5 strains. Sonnei and three Dysenteriae strains (D1, D8, and D10) are outside of the three main clusters but, nonetheless, are clearly within Escherichia coli. Boydii 13 was found to be distantly related to E. coli. Shigella strains, like the other pathogenic forms of E. coli, do not have a single evolutionary origin, indicating convergent evolution of Shigella phenotypic properties. We estimate the three main Shigella clusters to have evolved within the last 35,000 to 270,000 years, suggesting that shigellosis was one of the early infectious diseases of humans.

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In many song birds, males develop their songs as adults by imitating the songs of one or more tutors, memorized previously during a sensitive phase early in life. Previous work using two assays, the production of imitations by adult males and playback-induced calling by young birds during the sensitive phase for memorization, has shown that song birds can discriminate between their own and other species' songs. Herein I use both assays to show that male mountain white-crowned sparrows, Zonotrichia leucophrys oriantha, must learn to sing but have a genetic predisposition to memorize and learn the songs of their own subspecies. Playback tests to young naive birds before they even begin to sing reveal that birds give begging calls more in response to oriantha song than to songs of another species. After 10 days of tutoring with songs of either their own or another subspecies, birds continue to give stronger call responses to songs of their own subspecies, irrespective of whether they were tutored with them, and are more discriminating in distinguishing between different dialects of their own subspecies. The memory processes that facilitate recognition and discrimination of own-subspecies' song may also mediate the preferential imitation of song of a bird's own subspecies. Such perceptual biases could constrain the direction and rate of cultural evolution of learned songs.

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Factors that affect naïve T cell proliferation in syngeneic lymphopenic hosts were investigated. 2C T cell receptor (TCR) transgenic T cells lacking both CD8 and CD4 survived but hardly proliferated. Proliferation of CD8+ 2C cells was proportional to the abundance of cognate peptide/MHC complexes and was severely inhibited by injection of anti-CD8 antibody. Weakly reactive self-peptides slightly enhanced CD8+ 2C cell proliferation whereas a potent agonist peptide promoted much more rapid proliferation, but inflammation-stimulating adjuvant had only a small effect on the rate of cell proliferation. The findings suggest that under uniform lymphopenic conditions, the widely different rates of proliferation of T cells expressing various TCR, or the same TCR in the presence or absence of CD8, reflect the strength of interaction between TCR and MHC associated with particular self-peptides.