108 research outputs found

    Standing Swells Surveyed Showing Surprisingly Stable Solutions for the Lorenz '96 Model

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    The Lorenz '96 model is an adjustable dimension system of ODEs exhibiting chaotic behavior representative of dynamics observed in the Earth's atmosphere. In the present study, we characterize statistical properties of the chaotic dynamics while varying the degrees of freedom and the forcing. Tuning the dimensionality of the system, we find regions of parameter space with surprising stability in the form of standing waves traveling amongst the slow oscillators. The boundaries of these stable regions fluctuate regularly with the number of slow oscillators. These results demonstrate hidden order in the Lorenz '96 system, strengthening the evidence for its role as a hallmark representative of nonlinear dynamical behavior.Comment: 10 pages, 8 figure

    Soundings: the Newsletter of the Monterey Bay Chapter of the American Cetacean Society. 2006

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    (PDF contains 88 pages.

    The evolution of new combinations: drivers of British maritime engineering competitiveness during the nineteenth century

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    This work is an attempt to explore early British steamship innovation during the 19th century from the point of view of innovation studies. The proposed analytical framework draws on neo-Schumpeterian and evolutionary economics for understanding the patterns and factors behind the phenomenon of technical change in the capital good under analysis. The thesis aims at filling a gap in the maritime economic and technological history literature, namely the issues connected to the process through which modern (mechanically-propelled, iron-hulled, screw-driven) ocean transportation emerged. Two inter-related research questions are addressed: how and why did steamships evolve in the course of the 19th century? In other words, the present research focuses on describing the dynamics of technological evolution and on identifying the key drivers of those developments. While the thesis includes a review of the relevant literature (Part I), the main work consists of original empirical research (Parts II and III). The bulk of this work primarily rests on the compilation of two new main bodies of quantitative and qualitative evidence. First, a previously unpublished dataset on the population and characteristics of steamers is used to measure the rate and direction of technical change in steamers. Second, previously unpublished archival material is used to reconstruct the innovation processes of marine engineers and naval architects and the civil society arrangements around them. The results suggest a number of stylised facts and institutional variables that have been subject to little discussion in the extant literature. On one hand, time-series and other statistical analyses suggest a technological “take-off” of steamship performance by the mid-19th century. This turning point, which was the outcome of a complex but rapid process of structural reconfiguration (the transition from wood-paddle to iron-screw as the new “dominant design”), occurred between the late 1830s and the late 1840s particularly among cargo traders and unsubsidised packets. On the other hand, documentary evidence shows that such technological breakthroughs were preceded and supported by a specific set of institutional innovations. These included the emergence of voluntary engineering associations, technical mass media and a not-for-profit ship classification society within the British national system of innovation. The thesis argues that the process of revolutionary technological innovation leading to the economically efficient long-haul merchant steamer cannot be separated from the rise of a vibrant interactive environment promoting learning, knowledge integration and technological accumulation, which may be called a “technological public sphere”

    Active Materials

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    What is an active material? This book aims to redefine perceptions of the materials that respond to their environment. Through the theory of the structure and functionality of materials found in nature a scientific approach to active materials is first identified. Further interviews with experts from the natural sciences and humanities then seeks to question and redefine this view of materials to create a new definition of active materials

    Schistosomiasis control in China : strategy of control and rapid assessment of schistosomiasis risk by remote sensing (RS)and geographic information system (GIS)

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    Human schistosomiasis remains one of the most prevalent parasitic infections in the tropics and subtropics. The disease currently is endemic in 76 countries and territories and continues to be a major public health concern, especially in the developing world. It is estimated that 650 million people are at risk of infection. Among the 200 million people actually infected, 120 million are symptomatic and 20 million suffer severe disease. Although morbidity control – in line with recommendations put forth by the World Health Organization – has been carried out in China for more than 20 years, it is estimated that 90 million people still live in areas where they are at risk of infection, and 820,000 people are infected with the parasite, i.e. Schistosoma japonicum. The estimated area of intermediate host snail habitats comprise 3,436 km2, concentrated in the 5 lake regions along the Yangtze River that include the provinces of Anhui, Jiangsu, Jiangxi, Hubei and Hunan. The marshlands of the Poyang Lake region represent some of the strongholds for the transmission of S. japonicum. In these settings, for example, the percentages of acute cases and intermediate host snail habitats represent 79.5% and 96.4%, respectively. With the World Bank Loan Project (WBLP) to control schistosomiasis in China, the overall prevalence of S. japonicum was significantly reduced, but in highly endemic areas the re-infection rates are high. In the first part of the present thesis, I summarize the 50-year history of China’s experience and expertise in schistosomiasis control. Particular emphasis is placed on morbidity control and achievements made by the WBLP carried out between 1992 and 2001. Reviewing this body of literature reveals that morbidity control of schistosomiasis in China has been successful, and hence this strategy will continue to form the backbone of protecting people’s health. However, total expenditures have been considerable, and with the termination of the WBLP there is concern that schistosomiasis might re-emerge. In the second part of this thesis, I describe the successful development of a novel compound model to identify the habitats of Oncomelania hupensis, the intermediate host snail of S. japonicum, and hence the identification of high-risk areas of disease transmission. There are three findings that warrant particular notion. First, visual land use classification on multi-temporal Landsat images was performed for preliminary prediction of O. hupensis habitats. Second, extraction of the normalized difference vegetation index and the tasseled cap transformation greenness index were used for improved snail habitat prediction. Third, buffer zones with distances of 600 and 1,200 m were made around the predicted snail habitats to differentiate between high (>15%), moderate (3-15%) and low risk of S. japonicum infection prevalence (< 3%). Preliminary validation of the compound model against ground-based snail surveys in the Poyang Lake region revealed that the model had an excellent predictive ability. The model therefore holds promise for rapid and inexpensive identification of high-risk areas, and can guide subsequent control interventions, such as whether mass or selective chemotherapy should be employed. The model can also be used for diseases surveillance in general and the monitoring of ecological transformations on the transmission dynamics of S. japonicum, for example in the Three Gorges Dam area

    Wage Structures and Employment Outcomes in New Zealand, and Their Relationship to Technological Change

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    After 100 years at an historically low level, inequality began to rise in the late 20th century, a trend which was especially marked in the English-speaking countries including New Zealand. Various explanations have been advanced, but internationally the most favoured theory is skill-biased technological change, driven by the new information and communication technologies. This thesis used income and wage data from the New Zealand Population Census and the New Zealand Income Survey to examine wage trends between 1991 and 2004. As in other developed countries wage dispersion was increasing in the 1990s, though it appears to have slowed since 2001, and the increased inequality is strongly correlated with workers' skills and qualifications. There is also a correlation between new technology and earnings inequality, but this appears to be attributable to the demand for skills in the industries which are changing fastest, rather than anything intrinsic to the new technology

    Active Materials

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    What is an active material? This book aims to redefine perceptions of the materials that respond to their environment. Through the theory of the structure and functionality of materials found in nature a scientific approach to active materials is first identified. Further interviews with experts from the natural sciences and humanities then seeks to question and redefine this view of materials to create a new definition of active materials

    The years of high econometrics: A short history of the generation that reinvented economic

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    This book is an essay in biography and its subject matter is the collective effort of that brilliant generation of economists who aspired to transform economics into a rigorous science. The powerful econometric movement took shape in the 1930s, the years of high theory – the concept that Shackle used to describe the period of the inception of the Keynesian revolution, a period that cannot be thoroughly understood unless both movements are contrasted. In a sense, both the Keynesian revolution and the econometric revolution shared the same motivation: to extend the empirical capacity of economics, broadening its analytical scope and strengthening its capacity for designing a control policy. As the story unfurls, it becomes obvious that the young econometricians with Keynesian leanings were more radically engaged in such a task than the Cambridge circle itself, and this was the profound reason for a great deal of the harsh criticism and disappointment that they faced. Furthermore, the acceptance of the epistemological primacy of a very peculiar type of simple mathematical formalism contributed to the marginalisation of some of the major theoretical alternatives developed in the first half of the century. Evidence shows that the endorsement of the urgent political agenda for action against unemployment and the dangers of war were instrumental in determining the victory of a specific mathematical drive, and that the econometric programme as it came to be conceived in these incipient years was shaped by this movement. As a consequence of its impact, econometrics became a tool for the reconstruction of neoclassical economics, which sought to be redescribed in the language of mathematical formalism and statistical inference and estimation, and simultaneously responsible for the decay of heterodox alternatives elsewhere. In that sense, modern economics was a tributary of that success.info:eu-repo/semantics/publishedVersio
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