999 resultados para modular forms


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Recientemente, el paradigma de la computación en la nube ha recibido mucho interés por parte tanto de la industria como del mundo académico. Las infraestructuras cloud públicas están posibilitando nuevos modelos de negocio y ayudando a reducir costes. Sin embargo, una compañía podría desear ubicar sus datos y servicios en sus propias instalaciones, o tener que atenerse a leyes de protección de datos. Estas circunstancias hacen a las infraestructuras cloud privadas ciertamente deseables, ya sea para complementar a las públicas o para sustituirlas por completo. Por desgracia, las carencias en materia de estándares han impedido que las soluciones para la gestión de infraestructuras privadas se hayan desarrollado adecuadamente. Además, la multitud de opciones disponibles ha creado en los clientes el miedo a depender de una tecnología concreta (technology lock-in). Una de las causas de este problema es la falta de alineación entre la investigación académica y los productos comerciales, ya que aquella está centrada en el estudio de escenarios idealizados sin correspondencia con el mundo real, mientras que éstos consisten en soluciones desarrolladas sin tener en cuenta cómo van a encajar con los estándares más comunes o sin preocuparse de hacer públicos sus resultados. Con objeto de resolver este problema, propongo un sistema de gestión modular para infraestructuras cloud privadas enfocado en tratar con las aplicaciones en lugar de centrarse únicamente en los recursos hardware. Este sistema de gestión sigue el paradigma de la computación autónoma y está diseñado en torno a un modelo de información sencillo, desarrollado para ser compatible con los estándares más comunes. Este modelo divide el entorno en dos vistas, que sirven para separar aquello que debe preocupar a cada actor involucrado del resto de información, pero al mismo tiempo permitiendo relacionar el entorno físico con las máquinas virtuales que se despliegan encima de él. En dicho modelo, las aplicaciones cloud están divididas en tres tipos genéricos (Servicios, Trabajos de Big Data y Reservas de Instancias), para que así el sistema de gestión pueda sacar partido de las características propias de cada tipo. El modelo de información está complementado por un conjunto de acciones de gestión atómicas, reversibles e independientes, que determinan las operaciones que se pueden llevar a cabo sobre el entorno y que es usado para hacer posible la escalabilidad en el entorno. También describo un motor de gestión encargado de, a partir del estado del entorno y usando el ya mencionado conjunto de acciones, la colocación de recursos. Está dividido en dos niveles: la capa de Gestores de Aplicación, encargada de tratar sólo con las aplicaciones; y la capa del Gestor de Infraestructura, responsable de los recursos físicos. Dicho motor de gestión obedece un ciclo de vida con dos fases, para así modelar mejor el comportamiento de una infraestructura real. El problema de la colocación de recursos es atacado durante una de las fases (la de consolidación) por un resolutor de programación entera, y durante la otra (la online) por un heurístico hecho ex-profeso. Varias pruebas han demostrado que este acercamiento combinado es superior a otras estrategias. Para terminar, el sistema de gestión está acoplado a arquitecturas de monitorización y de actuadores. Aquella estando encargada de recolectar información del entorno, y ésta siendo modular en su diseño y capaz de conectarse con varias tecnologías y ofrecer varios modos de acceso. ABSTRACT The cloud computing paradigm has raised in popularity within the industry and the academia. Public cloud infrastructures are enabling new business models and helping to reduce costs. However, the desire to host company’s data and services on premises, and the need to abide to data protection laws, make private cloud infrastructures desirable, either to complement or even fully substitute public oferings. Unfortunately, a lack of standardization has precluded private infrastructure management solutions to be developed to a certain level, and a myriad of diferent options have induced the fear of lock-in in customers. One of the causes of this problem is the misalignment between academic research and industry ofering, with the former focusing in studying idealized scenarios dissimilar from real-world situations, and the latter developing solutions without taking care about how they f t with common standards, or even not disseminating their results. With the aim to solve this problem I propose a modular management system for private cloud infrastructures that is focused on the applications instead of just the hardware resources. This management system follows the autonomic system paradigm, and is designed around a simple information model developed to be compatible with common standards. This model splits the environment in two views that serve to separate the concerns of the stakeholders while at the same time enabling the traceability between the physical environment and the virtual machines deployed onto it. In it, cloud applications are classifed in three broad types (Services, Big Data Jobs and Instance Reservations), in order for the management system to take advantage of each type’s features. The information model is paired with a set of atomic, reversible and independent management actions which determine the operations that can be performed over the environment and is used to realize the cloud environment’s scalability. From the environment’s state and using the aforementioned set of actions, I also describe a management engine tasked with the resource placement. It is divided in two tiers: the Application Managers layer, concerned just with applications; and the Infrastructure Manager layer, responsible of the actual physical resources. This management engine follows a lifecycle with two phases, to better model the behavior of a real infrastructure. The placement problem is tackled during one phase (consolidation) by using an integer programming solver, and during the other (online) with a custom heuristic. Tests have demonstrated that this combined approach is superior to other strategies. Finally, the management system is paired with monitoring and actuators architectures. The former able to collect the necessary information from the environment, and the later modular in design and capable of interfacing with several technologies and ofering several access interfaces.

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Logic programming (LP) is a family of high-level programming languages which provides high expressive power. With LP, the programmer writes the properties of the result and / or executable specifications instead of detailed computation steps. Logic programming systems which feature tabled execution and constraint logic programming have been shown to increase the declarativeness and efficiency of Prolog, while at the same time making it possible to write very expressive programs. Tabled execution avoids infinite failure in some cases, while improving efficiency in programs which repeat computations. CLP reduces the search tree and brings the power of solving (in)equations over arbitrary domains. Similarly to the LP case, CLP systems can also benefit from the power of tabling. Previous implementations which take ful advantage of the ideas behind tabling (e.g., forcing suspension, answer subsumption, etc. wherever it is necessary to avoid recomputation and terminate whenever possible) did not offer a simple, well-documented, easy-to-understand interface. This would be necessary to make the integratation of arbitrary CLP solvers into existing tabling systems possible. This clearly hinders a more widespread usage of the combination of both facilities. In this thesis we examine the requirements that a constraint solver must fulfill in order to be interfaced with a tabling system. We propose and implement a framework, which we have called Mod TCLP, with a minimal set of operations (e.g., entailment checking and projection) which the constraint solver has to provide to the tabling engine. We validate the design of Mod TCLP by a series of use cases: we re-engineer a previously existing tabled constrain domain (difference constraints) which was connected in an ad-hoc manner with the tabling engine in Ciao Prolog; we integrateHolzbauer’s CLP(Q) implementationwith Ciao Prolog’s tabling engine; and we implement a constraint solver over (finite) lattices. We evaluate its performance with several benchmarks that implement a simple abstract interpreter whose fixpoint is reached by means of tabled execution, and whose domain operations are handled by the constraint over (finite) lattices, where TCLP avoids recomputing subsumed abstractions.---ABSTRACT---La programación lógica con restricciones (CLP) y la tabulación son extensiones de la programación lógica que incrementan la declaratividad y eficiencia de Prolog, al mismo tiempo que hacen posible escribir programasmás expresivos. Las implementaciones anteriores que integran completamente ambas extensiones, incluyendo la suspensión de la ejecución de objetivos siempre que sea necesario, la implementación de inclusión (subsumption) de respuestas, etc., en todos los puntos en los que sea necesario para evitar recomputaciones y garantizar la terminación cuando sea posible, no han proporcionan una interfaz simple, bien documentada y fácil de entender. Esta interfaz es necesaria para permitir integrar resolutores de CLP arbitrarios en el sistema de tabulación. Esto claramente dificulta un uso más generalizado de la integración de ambas extensiones. En esta tesis examinamos los requisitos que un resolutor de restricciones debe cumplir para ser integrado con un sistema de tabulación. Proponemos un esquema (y su implementación), que hemos llamadoMod TCLP, que requiere un reducido conjunto de operaciones (en particular, y entre otras, entailment y proyección de almacenes de restricciones) que el resolutor de restricciones debe ofrecer al sistema de tabulación. Hemos validado el diseño de Mod TCLP con una serie de casos de uso: la refactorización de un sistema de restricciones (difference constraints) previamente conectado de un modo ad-hoc con la tabulación de Ciao Prolog; la integración del sistema de restricciones CLP(Q) de Holzbauer; y la implementación de un resolutor de restricciones sobre retículos finitos. Hemos evaluado su rendimiento con varios programas de prueba, incluyendo la implementación de un intérprete abstracto que alcanza su punto fijo mediante el sistema de tabulación y en el que las operaciones en el dominio son realizadas por el resolutor de restricciones sobre retículos (finitos) donde TCLP evita la recomputación de valores abstractos de las variables ya contenidos en llamadas anteriores.

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Coordinación Modular

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Los muros cortina modulares están constituidos por paneles prefabricados que se fijan al edificio a través de anclajes a lo largo del borde del forjado. El proceso de prefabricación garantiza buena calidad y control de los acabados y el proceso de instalación es rápido y no requiere andamiaje. Por estas razones su uso está muy extendido en torres. Sin embargo, el diseño de los marcos de aluminio podría ser más eficiente si se aprovechara la rigidez de los vidrios para reducir la profundidad estructural de los montantes. Asimismo, se podrían reducir los puentes térmicos en las juntas si se sustituyeran los marcos por materiales de menor conductividad térmica que el aluminio. Esta investigación persigue desarrollar un muro cortina alternativo que reduzca la profundidad estructural, reduzca la transmisión térmica en las juntas y permita un acabado enrasado al interior, sin que sobresalgan los montantes. La idea consiste en conectar un marco de material compuesto de fibra de vidrio a lo largo del borde del vidrio aislante a través de adhesivos estructurales para así movilizar una acción estructural compuesta entre los dos vidrios y lograr una baja transmitancia térmica. El marco ha de estar integrado en la profundidad del vidrio aislante. En una primera fase se han efectuado cálculos estructurales y térmicos preliminares para evaluar las prestaciones a un nivel esquemático. Además, se han realizado ensayos a flexión en materiales compuestos de fibra de vidrio y ensayos a cortante en las conexiones adhesivas entre vidrio y material compuesto. Con la información obtenida se ha seleccionado el material del marco y del adhesivo y se han efectuado cambios sobre el diseño original. Los análisis numéricos finales demuestran una reducción de la profundidad estructural de un 80% y una reducción de la transmisión térmica de un 6% en comparación con un sistema convencional tomado como referencia. El sistema propuesto permite obtener acabados enrasados. ABSTRACT Unitised curtain wall systems consist of pre manufactured cladding panels which can be fitted to the building via pre fixed brackets along the edge of the floor slab. They are universally used for high rise buildings because the factory controlled assembly of units ensures high quality and allows fast installation without external access. However, its frame is structurally over-dimensioned because it is designed to carry the full structural load, failing to take advantage of potential composite contribution of glass. Subsequently, it is unnecessarily deep, occupying valuable space, and protrudes to the inside, causing visual disruption. Moreover, it is generally made of high thermal conductivity metal alloys, contributing to substantial thermal transmission at joints. This research aims to develop a novel frame-integrated unitised curtain wall system that will reduce thermal transmission at joints, reduce structural depth significantly and allow an inside flush finish. The idea is to adhesively bond a Fibre Reinforced Polymer (FRP) frame to the edge of the Insulated Glass Unit (IGU), thereby achieving composite structural behaviour and low thermal transmittance. The frame is to fit within the glazing cavity depth. Preliminary analytical structural and numerical thermal calculations are carried out to assess the performance of an initial schematic design. 4-point bending tests on GFRP and single-lap shear tests on bonded connections between GFRP and glass are performed to inform the frame and adhesive material selection process and to characterise these materials. Based on the preliminary calculations and experimental tests, some changes are put into effect to improve the performance of the system and mitigate potential issues. Structural and thermal numerical analysis carried out on the final detail design confirm a reduction of the structural depth to almost one fifth and a reduction of thermal transmission of 6% compared to a benchmark conventional system. A flush glazed appearance both to the inside and the outside are provided while keeping the full functionality of a unitised system.

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Tamaño y densidad son atributos imprescindibles para la caracterización de cualquier ciudad, sin embargo no siempre se les presta la misma atención. Mientras la densidad ocupa un lugar destacado en cualquier manual de planificación urbana, como variable crítica para modular la intervención urbanística, el tamaño de la ciudad tiende a tomarse como un imponderable más allá del control de la planificación. Sin embargo, no está claro que ambas variables se puedan analizar de forma autónoma, ya que las interrelaciones entre ambas son significativas. Con el fin de evaluar cómo se influyen mutuamente tamaño y densidad se plantea una metodología novedosa adaptada a las nuevas formas contemporáneas de urbanización que combina una delimitación funcional de las áreas urbanas con un análisis de su morfología en términos de densidad y compacidad. Los resultados obtenidos a partir de una muestra de 47 áreas urbanas españolas permiten clarificar algunos aspectos de la relación entre tamaño y densidad. Las grandes metrópolis españolas presentan valores relativamente altos de densidad y compacidad, pero los valores más elevados de ambos valores están presentes en áreas urbanas de tamaño intermedio o pequeño. En realidad se puede apreciar una enorme diversidad entre las áreas urbanas intermedias y pequeñas que desaparece casi por completo en las más grandes. Otro aspecto reseñable es la constatación de que densidad y compacidad son variables absolutamente independientes: existen áreas urbanas densas y compactas, pero también densas y poco compactas, o compactas pero poco densas. Sobre esta base, se propone una caracterización de la tipología tradicional de las ciudades españolas. Las áreas urbanas del Cantábrico presentan una alta densidad pero baja compacidad, en gran medida por la difícil orografía; por el contrario la áreas urbanas del interior presentan baja densidad y valores muy diversos de compacidad. Finalmente las áreas urbanas mediterráneas se caracterizan más por su alta compacidad que por su densidad, que es muy variable. En general los resultados obtenidos reflejan adecuadamente aspectos conocidos de la diversidad urbana española, pero también otros menos evidentes. Las conclusiones del estudio están muy mediatizadas por el contexto español, pero la metodología empleada ha demostrado ser de gran utilidad para el análisis de los territorios urbanos contemporáneos. ABSTRACT Size and density are essential attributes for characterizing cities, however they don't always deserve the same attention. While density is considered a critical variable in every urban planning guidebook, city size tends to be taken as an imponderable beyond the control of planning. However, it is unclear whether both variables can be analyzed independently, because their reciprocal influences are evident. To assess how city size and urban density influence each other, we propose a new methodology adapted to contemporary forms of urbanization, bringing together urban areas functional delimitation and morphological analysis in terms of density and compactness. Results obtained from a sample of 47 Spanish urban areas clarify some aspects of the size-density link. The largest Spanish urban areas are relatively dense and compact, but the highest values of both density and compactness are found in intermediate or small urban areas. Actually there is a huge diversity among intermediate and small urban areas which almost disappears in larger ones. Another noteworthy aspect is the realization that density and compactness are absolutely independent variables: there are dense and compact urban areas, but also low-density compact, and low-compactness dense areas. On this basis, we make a revision of the tradicional classification of Spanish urban areas. Cantabrian urban areas display high density and low compactness, largely because of the difficult terrain; on the contrary, inland urban areas exhibit low density and very different values of compactness. Finally, Mediterranean urban areas are characterized more by its high compactness than by its density, which is remarkably variable. In general results accurately reflect known aspects of Spanish urban diversity, but they also expose less obvious attributes. These findings may be closedly related to Spanish context, but the methodology has proven a useful tool for analyzing contemporary urban areas.

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Linear Fresnel collectors are identified as a technology that should play a main role in order to reduce cost of Concentrating Solar Power. An optical and thermal analysis of the different blocks of the solar power plant is carried out, where Fresnel arrays are compared with the most extended linear technology: parabolic trough collectors. It is demonstrated that the optical performance of Fresnel array is very close to that of PTC, with similar values of maximum flux intensities. In addition, if the heat carrier fluid flows in series by the tubes of the receiver, relatively high thermal efficiencies are achieved. Thus, an annual solar to electricity efficiency of 19% is expected, which is similar to the state of the art in PTCs; this is done with a reduction of costs, thanks to lighter structures, that drives to an estimation of LCOE of around 6.5 c€/kWh.

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Presenter, student and teacher evaluation forms for the 6th Annual Lincoln University Sonia Kovalevsky Math for Girls Day program flyer on April 29, 2011.

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Presenter, student and teacher evaluation forms for the 9th Annual Lincoln University Sonia Kovalevsky Math for Girls Day program flyer on April 25, 2014.

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Inositol polyphosphate 4-phosphatase (4-phosphatase) is an enzyme that catalyses the hydrolysis of the 4-position phosphate from phosphatidylinositol 3,4-bisphosphate [PtdIns(3,4)P2]. In human platelets the formation of this phosphatidylinositol, by the actions of phosphatidylinositol 3-kinase (PI 3-kinase), correlates with irreversible platelet aggregation. We have shown previously that a phosphatidylinositol 3,4,5-trisphosphate 5-phosphatase forms a complex with the p85 subunit of PI 3-kinase. In this study we investigated whether PI 3-kinase also forms a complex with the 4-phosphatase in human platelets. Immunoprecipitates of the p85 subunit of PI 3-kinase from human platelet cytosol contained 4-phosphatase enzyme activity and a 104-kDa polypeptide recognized by specific 4-phosphatase antibodies. Similarly, immunoprecipitates made using 4-phosphatase-specific antibodies contained PI 3-kinase enzyme activity and an 85-kDa polypeptide recognized by antibodies to the p85 adapter subunit of PI 3-kinase. After thrombin activation, the 4-phosphatase translocated to the actin cytoskeleton along with PI 3-kinase in an integrin- and aggregation-dependent manner. The majority of the PI 3-kinase/4-phosphatase complex (75%) remained in the cytosolic fraction. We propose that the complex formed between the two enzymes serves to localize the 4-phosphatase to sites of PtdIns(3,4)P2 production.

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The receptor 2B4 belongs to the Ig superfamily and is found on the surface of all murine natural killer (NK) cells as well as T cells displaying non-MHC-restricted cytotoxicity. Previous studies have suggested that 2B4 is an activating molecule because cross-linking of this receptor results in increased cytotoxicity and γ-interferon secretion as well as granule exocytosis. However, it was recently shown that the gene for 2B4 encodes two different products that arise by alternative splicing. These gene products differ solely in their cytoplasmic domains. One form has a cytoplasmic tail of 150 amino acids (2B4L) and the other has a tail of 93 amino acids (2B4S). To determine the function of each receptor, cDNAs for 2B4S and 2B4L were transfected into the rat NK cell line RNK-16. Interestingly, the two forms of 2B4 had opposing functions. 2B4S was able to mediate redirected lysis of P815 tumor targets, suggesting that this form represents an activating receptor. However, 2B4L expression led to an inhibition of redirected lysis of P815 targets when the mAb 3.2.3 (specific for rat NKRP1) was used. In addition, 2B4L constitutively inhibits lysis of YAC-1 tumor targets. 2B4L is a tyrosine phosphoprotein, and removal of domains containing these residues abrogates its inhibitory function. Like other inhibitory receptors, 2B4L associates with the tyrosine phosphatase SHP-2. Thus, 2B4L is an inhibitory receptor belonging to the Ig superfamily.

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The capacity for neuromodulation and biophysical plasticity is a defining feature of most mature neuronal cell types. In several cases, modulation at the level of the individual neuron has been causally linked to changes in the functional output of a neuronal circuit and subsequent adaptive changes in the organism’s behavioral responses. Understanding how such capacity for neuromodulation develops therefore may provide insights into the mechanisms both of neuronal development and learning and memory. We have examined the development of multiple forms of neuromodulation triggered by a common neurotransmitter, serotonin, in the pleural sensory neurons of Aplysia californica. We have found that multiple signaling cascades within a single neuron develop sequentially, with some being expressed only very late in development. In addition, our data suggest a model in which, within a single neuromodulatory pathway, the elements of the signaling cascade are developmentally expressed in a “retrograde” manner with the ionic channel that is modulated appearing early in development, functional elements in the second messenger cascade appearing later, and finally, coupling of the second messenger cascade to the serotonin receptor appearing quite late. These studies provide the characterization of the development of neuromodulation at the level of an identified cell type and offer insights into the potential roles of neuromodulatory processes in development and adult plasticity.

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The SCF ubiquitin ligase complex of budding yeast triggers DNA replication by catalyzing ubiquitination of the S phase cyclin-dependent kinase inhibitor SIC1. SCF is composed of three proteins—ySKP1, CDC53 (Cullin), and the F-box protein CDC4—that are conserved from yeast to humans. As part of an effort to identify components and substrates of a putative human SCF complex, we isolated hSKP1 in a two-hybrid screen with hCUL1, the closest human homologue of CDC53. Here, we show that hCUL1 associates with hSKP1 in vivo and directly interacts with both hSKP1 and the human F-box protein SKP2 in vitro, forming an SCF-like particle. Moreover, hCUL1 complements the growth defect of yeast cdc53ts mutants, associates with ubiquitination-promoting activity in human cell extracts, and can assemble into functional, chimeric ubiquitin ligase complexes with yeast SCF components. Taken together, these data suggest that hCUL1 functions as part of an SCF ubiquitin ligase complex in human cells. Further application of biochemical assays similar to those described here can now be used to identify regulators/components of hCUL1-based SCF complexes, to determine whether the hCUL2–hCUL5 proteins also are components of ubiquitin ligase complexes in human cells, and to screen for chemical compounds that modulate the activities of the hSKP1 and hCUL1 proteins.

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Multidrug resistance mediated by the drug efflux protein, P-glycoprotein (P-gp), is one mechanism that tumor cells use to escape death induced by chemotherapeutic agents. However, the mechanism by which P-gp confers resistance to a large variety of structurally diverse molecules has remained elusive. In this study, classical multidrug resistant human CEM and K562 tumor cell lines expressing high levels of P-gp were less sensitive to multiple forms of caspase-dependent cell death, including that mediated by cytotoxic drugs and ligation of Fas. The DNA fragmentation and membrane damage inflicted by these stimuli were defined as caspase dependent by various soluble peptide fluoromethylketone caspase inhibitors. Inhibition of P-gp function by the anti-P-gp mAb MRK-16 or verapamil could reverse resistance to these forms of cell death. Inhibition of P-gp function also enhanced drug or Fas-mediated activation of caspase-3 in drug-resistant CEM cells. By contrast, caspase-independent cell death events in the same cells, including those mediated by pore-forming proteins or intact NK cells, were not affected by P-gp expression. These observations suggest that, in addition to effluxing drugs, P-gp may play a specific role in regulating some caspase-dependent apoptotic pathways.

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When administered intracerebroventricularly to mice performing various learning tasks involving either short-term or long-term memory, secreted forms of the β-amyloid precursor protein (APPs751 and APPs695) have potent memory-enhancing effects and block learning deficits induced by scopolamine. The memory-enhancing effects of APPs were observed over a wide range of extremely low doses (0.05-5,000 pg intracerebroventricularly), blocked by anti-APPs antisera, and observed when APPs was administered either after the first training session in a visual discrimination or a lever-press learning task or before the acquisition trial in an object recognition task. APPs had no effect on motor performance or exploratory activity. APPs695 and APPs751 were equally effective in the object recognition task, suggesting that the memory-enhancing effect of APPs does not require the Kunitz protease inhibitor domain. These data suggest an important role for APPss on memory processes.