889 resultados para push-pull chromophores
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Non-cognitive skills have caught the attention of current education policy writers in Canada. Within the last 10 years, almost every province has produced a document including the importance of supporting non-cognitive skills in K-12 students in the classroom. Although often called different names (such as learning skills, cross curricular competencies, and 20th Century Skills) and occasionally viewed through different lenses (such as emotional intelligence skills, character skills, and work habits), what unifies non-cognitive skills within the policy documents is the claim that students that are strong in these skills are more successful in academic achievement and are more successful in post-secondary endeavors. Though the interest from policy-makers and educators is clear, there are still many questions about non-cognitive skills that have yet to be answered. These include: What skills are the most important for teacher’s to support in the classroom? What are these skills’ exact contributions to student success? How can teachers best support these skills? Are there currently reliable and valid measures of these skills? These are very important questions worth answering if Canadian teachers are expected to support non-cognitive skills in their classrooms with an already burdened workload. As well, it can begin to untangle the plethora of research that exists within the non-cognitive realm. Without a critical look at the current literature, it is impossible to ensure that these policies are effective in Canadian classrooms, and to see an alignment between research and policy. Upon analysis of Canadian curriculum, five non-cognitive skills were found to be the most prevalent among many of the provinces: Self-Regulation, Collaboration, Initiative, Responsibility and Creativity. The available research literature was then examined to determine the utility of teaching these skills in the classroom (can students improve on these skills, do these skills impact other aspects of students’ lives, and are there methods to validly and reliably assess these skills). It was found that Self-Regulation and Initiative had the strongest basis for being implemented in the classroom. On the other hand, Creativity still requires a lot more justification in terms of its impact on students’ lives and ability to assess in the classroom.
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Mallorca, the largest of the Balearic Islands, is a well-known summer holidays destination; an ideal place to relax and enjoy the sun and the sea. That tourist gaze reflected on postcards results from advertising campaigns, where cinema played an important role with documentaries and fiction films. The origins of that iconography started in the decades of the 1920’s and 1930’s, reflecting the so-called myth of the “island of calm”. On the other hand, the films of the 1950’s and 1960’s created new stereotypes related to the mass tourism boom. Busy beaches and the white bodies of tourists replaced white sandy beaches, mountains and landscapes shown up in the movies of the early decades of the 20th century. Besides, hotels and nightclubs also replaced monuments, rural landscapes and folk exhibitions. These tourist images mirror the social and spatial transformations of Mallorca, under standardization processes like other seaside mass tourist destinations. The identity was rebuilt on the foundations of "modernity". Although "balearization" has not ceased, nowadays filmmaking about Mallorca is advertising again a stereotype close to that one of the 1920s and 1930s, glorifying the myth of the "island of calm". This singular identity makes the island more profitable for capital that searches socio-spatial differentiation in post-fordist times.
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Thesis (Ph.D.)--University of Washington, 2016-08
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A locational duality in port-related distribution activities is emerging. In some regions, distribution activities have moved from ports to inland locations, driven in part by ‘push factors’ such as port congestion and scarcity of land for container handling activities, or by ‘pull factors’ such as the growth of intermodal corridors, the influence of inland terminals and the changing economic geography in the hinterland. In other regions, ports retain their traditional role as centres of distribution and warehousing activity. More recently, the focus on ‘port-centric logistics’ is indicative that some regions are refocusing on ports as potential locations for large distribution centres. The result has been a growing competition, but also complementarity, between ports and inland locations concerning the location of distribution activities, driven not only by market forces but also by institutional settings and the governance relations between the actors involved. This report provides an overview of regional differences across the world in order to develop a framework identifying for which type of distribution activities ports are suitable locations and which activities are best suited to the hinterland, taking into account geographical, economic and logistics settings. Empirical evidence is derived from a variety of regions in Europe, North America, South America, Southern Africa and Asia.
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Over the last decade, success of social networks has significantly reshaped how people consume information. Recommendation of contents based on user profiles is well-received. However, as users become dominantly mobile, little is done to consider the impacts of the wireless environment, especially the capacity constraints and changing channel. In this dissertation, we investigate a centralized wireless content delivery system, aiming to optimize overall user experience given the capacity constraints of the wireless networks, by deciding what contents to deliver, when and how. We propose a scheduling framework that incorporates content-based reward and deliverability. Our approach utilizes the broadcast nature of wireless communication and social nature of content, by multicasting and precaching. Results indicate this novel joint optimization approach outperforms existing layered systems that separate recommendation and delivery, especially when the wireless network is operating at maximum capacity. Utilizing limited number of transmission modes, we significantly reduce the complexity of the optimization. We also introduce the design of a hybrid system to handle transmissions for both system recommended contents ('push') and active user requests ('pull'). Further, we extend the joint optimization framework to the wireless infrastructure with multiple base stations. The problem becomes much harder in that there are many more system configurations, including but not limited to power allocation and how resources are shared among the base stations ('out-of-band' in which base stations transmit with dedicated spectrum resources, thus no interference; and 'in-band' in which they share the spectrum and need to mitigate interference). We propose a scalable two-phase scheduling framework: 1) each base station obtains delivery decisions and resource allocation individually; 2) the system consolidates the decisions and allocations, reducing redundant transmissions. Additionally, if the social network applications could provide the predictions of how the social contents disseminate, the wireless networks could schedule the transmissions accordingly and significantly improve the dissemination performance by reducing the delivery delay. We propose a novel method utilizing: 1) hybrid systems to handle active disseminating requests; and 2) predictions of dissemination dynamics from the social network applications. This method could mitigate the performance degradation for content dissemination due to wireless delivery delay. Results indicate that our proposed system design is both efficient and easy to implement.
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In the last sixty years a steadily maintained process of convergence towards the Castilian national standard has been occurring in Southern Spain affecting urban middle-class speakers’ varieties, particularly phonology and lexis. As a consequence, unmarked features characterising innovative southern pronunciation have become less frequent and, at the same time, certain standard marked features have been adapted to the southern phonemic inventory. Then, urban middle-class varieties have progressively been stretching out the distance separating them from working-class and rural varieties, and bringing them closer to central Castilian varieties. Intermediate, yet incipient koineised varieties have been described including also transitional Murcia and Extremadura dialects (Hernández & Villena 2009, Villena, Vida & von Essen 2015). (1) Some of the standard phonologically marked features have spread out among southern speakers exclusively based on their mainstream social prestige and producing not only changes in obstruent phoneme inventory –i.e. acquisition of /s/ vs. /θ/ contrast, but also standstill and even reversion of old consonant push- or pull-chain shifts –e.g. /h/ or /d/ fortition, affricate /ʧ/, etc. as well as traditional lexis shift (Villena et al. 2016). Internal (grammar and word frequency) and external (stratification, network and style) factors constraining those features follow similar patterns in the Andalusian speech communities analysed so far (Granada, Malaga) but when we zoom in on central varieties, which are closer to the national standard and then more conservative, differences in frequency increase and conflict sites emerge. (2) Unmarked ‘natural’ phonological features characterising southern dialects, particularly deletion of syllable-final consonant, do not keep pace with this trend of convergence towards the standard. Thus a combination of southern innovative syllable-final and standard conservative onset-consonant features coexist. (3). The main idea is that this intermediate variety is formed through changes suggesting that Andalusian speakers look for the best way of accepting marked prestige features without altering coherence within their inventory. Either reorganisation of the innovative phonemic system in such a way that it may include Castilian and standard /s/ vs. /θ/ contrast or re-syllabification of aspirated /s/ before dental stop are excellent examples of how and why linguistic features are able to integrate intermediate varieties between the dialect-standard continuum.
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info:eu-repo/semantics/publishedVersion
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El siguiente estudio de caso analiza la influencia de la llegada de la migración infantil indocumentada centroamericana en la reformulación de la política migratoria de Estados Unidos en el período 2010-2014. Enfocándose en el caso de Honduras para dar a conocer y analizar las causas que crean las dinámicas migratorias por parte de los menores, este trabajo analiza como la llegada de estas poblaciones genera ciertos efectos en el proceso de toma de decisión de las políticas internas de los Estados Unidos. Por un lado, para resaltar las características del fenómeno migratorio, se utilizan las teorías de redes sociales y la teoría push and pull. Por otro, mediante los conceptos de Sensibilidad y Vulnerabilidad expuestos en la teoría de la Interdependencia Compleja de las Relaciones Internacionales, como también el concepto de Seguridad Societal propuesto por Barry Buzan se estudia el nivel de influencia del fenómeno infantil en el gobierno norteamericano.
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The simulation of ultrafast photoinduced processes is a fundamental step towards the understanding of the underlying molecular mechanism and interpretation/prediction of experimental data. Performing a computer simulation of a complex photoinduced process is only possible introducing some approximations but, in order to obtain reliable results, the need to reduce the complexity must balance with the accuracy of the model, which should include all the relevant degrees of freedom and a quantitatively correct description of the electronic states involved in the process. This work presents new computational protocols and strategies for the parameterisation of accurate models for photochemical/photophysical processes based on state-of-the-art multiconfigurational wavefunction-based methods. The required ingredients for a dynamics simulation include potential energy surfaces (PESs) as well as electronic state couplings, which must be mapped across the wide range of geometries visited during the wavepacket/trajectory propagation. The developed procedures allow to obtain solid and extended databases reducing as much as possible the computational cost, thanks to, e.g., specific tuning of the level of theory for different PES regions and/or direct calculation of only the needed components of vectorial quantities (like gradients or nonadiabatic couplings). The presented approaches were applied to three case studies (azobenzene, pyrene, visual rhodopsin), all requiring an accurate parameterisation but for different reasons. The resulting models and simulations allowed to elucidate the mechanism and time scale of the internal conversion, reproducing or even predicting new transient experiments. The general applicability of the developed protocols to systems with different peculiarities and the possibility to parameterise different types of dynamics on an equal footing (classical vs purely quantum) prove that the developed procedures are flexible enough to be tailored for each specific system, and pave the way for exact quantum dynamics with multiple degrees of freedom.
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Una sempre crescente quantità di informazione digitale viene condivisa tra miliardi di dispositivi connessi in ogni angolo del pianeta. Per riuscire a sfruttare una banda più ampia ed aumentare la velocità di trasmissione dei dati, i prossimi standard di telecomunicazioni wireless dovranno adoperare frequenze operative sempre più alte, cercando di rispettare stringenti specifiche in termini di affidabilità ed efficienza energetica. In generale, le prestazioni di un transistor dipenderanno dalle terminazioni a cui esso è collegato. In un setup di caratterizzazione e test, è possibile, tramite un metodo noto come load pull attivo, sintetizzare un determinato valore di impedenza ad uno o più piani di riferimento all'interno di un circuito. Questa strategia si basa in generale sulla manipolazione del rapporto tra onde entranti ed uscenti da un piano di riferimento del dispositivo. Se da una parte tecniche di load pull attivo a banda larga a radiofrequenza hanno ricevuto un notevole interesse sia commerciale che accademico, dall'altra le strategie per la sintesi di impedenze presenti al terminale di alimentazione dell'amplificatore, sono state meno investigate. Questo elaborato si propone di introdurre un algoritmo per il load pull attivo a banda base per amplificatori per applicazioni RF. Dopo un'introduzione sui modelli comportamentali degli amplificatori, è stato considerato il problema degli effetti di memoria. È stata poi descritta la tecnica per l'emulazione di impedenze. Dapprima, è stato considerato il caso lineare. Poi, tramite il design di un amplificatore di potenza per applicazioni a radio frequenza usato come device under test (DUT), sono stati affrontati due esempi in presenza di non linearità, verificando la correttezza della tecnica proposta tramite l'uso di simulazioni.
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Yellowing is an undesirable phenomenon that is common in people with white and grey hair. Because white hair has no melanin, the pigment responsible for hair colour, the effects of photodegradation are more visible in this type of hair. The origin of yellowing and its relation to photodegradation processes are not properly established, and many questions remain open in this field. In this work, the photodegradation of grey hair was investigated as a function of the wavelength of incident radiation, and its ultrastructure was determined, always comparing the results obtained for the white and black fibres present in grey hair with the results of white wool. The results presented herein indicate that the photobehaviour of grey hair irradiated with a mercury lamp or with solar radiation is dependent on the wavelength range of the incident radiation and on the initial shade of yellow in the sample. Two types of grey hair were used: (1) blended grey hair (more yellow) and (2) grey hair from a single-donor (less yellow). After exposure to a full-spectrum mercury lamp for 200 h, the blended white hair turned less yellow (the yellow-blue difference, Db(*) becomes negative, Db(*)=-6), whereas the white hair from the single-donor turned slightly yellower (Db(*)=2). In contrast, VIS+IR irradiation resulted in bleaching in both types of hair, whereas a thermal treatment (at 81 °C) caused yellowing of both types of hair, resulting in a Db(*)=3 for blended white hair and Db(*)=9 for single-donor hair. The identity of the yellow chromophores was investigated by UV-Vis spectroscopy. The results obtained with this technique were contradictory, however, and it was not possible to obtain a simple correlation between the sample shade of yellow and the absorption spectra. In addition, the results are discussed in terms of the morphology differences between the pigmented and non-pigmented parts of grey hair, the yellowing and bleaching effects of grey hair, and the occurrence of dark-follow reactions.
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Friction and triboelectrification of materials show a strong correlation during sliding contacts. Friction force fluctuations are always accompanied by two tribocharging events at metal-insulator [e.g., polytetrafluoroethylene (PTFE)] interfaces: injection of charged species from the metal into PTFE followed by the flow of charges from PTFE to the metal surface. Adhesion maps that were obtained by atomic force microscopy (AFM) show that the region of contact increases the pull-off force from 10 to 150 nN, reflecting on a resilient electrostatic adhesion between PTFE and the metallic surface. The reported results suggest that friction and triboelectrification have a common origin that must be associated with the occurrence of strong electrostatic interactions at the interface.