916 resultados para Mitigation of environmental impacts
Resumo:
The following investigation characterises the interaction between temperature and growth in psychrophilic, mesophilic and thermophilic fungi in order to gain further insight into the physiological mechanisms underlying fungal growth at extreme temperatures. In the first part of the investigation, the effect of environmental temperature on the growth of vegetative mycelium and sporangiospore production and germination was considered in order to determine the cardinal temperatures of these activities in different thermal groups. Subsequent investigations of plasma membrane permeability suggested that plasma membrane structure and function may be significant in establishing both the upper and lower growth temperature limits characteristic of psychrophiles, mesophiles and thermophiles. Analysis of the plasma membrane fractions revealed significant differences in membrane phospholipid composition between these thermal groups and it is suggested that the differing cardinal growth temperatures characteristic of psychrophilic, mesophilic and thermophilic fungi reflect the temperature ranges over which these organisms exhibit levels of plasma membrane fluidity sufficient to maintain membrane-associated growth processes. In contrast, the membrane protein components appear uniform in both character and thermostability and are therefore unlikely to contribute to this phenomenon.
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Product reliability and its environmental performance have become critical elements within a product's specification and design. To obtain a high level of confidence in the reliability of the design it is customary to test the design under realistic conditions in a laboratory. The objective of the work is to examine the feasibility of designing mechanical test rigs which exhibit prescribed dynamical characteristics. The design is then attached to the rig and excitation is applied to the rig, which then transmits representative vibration levels into the product. The philosophical considerations made at the outset of the project are discussed as they form the basis for the resulting design methodologies. It is attempted to directly identify the parameters of a test rig from the spatial model derived during the system identification process. It is shown to be impossible to identify a feasible test rig design using this technique. A finite dimensional optimal design methodology is developed which identifies the parameters of a discrete spring/mass system which is dynamically similar to a point coordinate on a continuous structure. This design methodology is incorporated within another procedure which derives a structure comprising a continuous element and a discrete system. This methodology is used to obtain point coordinate similarity for two planes of motion, which is validated by experimental tests. A limitation of this approach is that it is impossible to achieve multi-coordinate similarity due to an interaction of the discrete system and the continuous element at points away from the coordinate of interest. During the work the importance of the continuous element is highlighted and a design methodology is developed for continuous structures. The design methodology is based upon distributed parameter optimal design techniques and allows an initial poor design estimate to be moved in a feasible direction towards an acceptable design solution. Cumulative damage theory is used to provide a quantitative method of assessing the quality of dynamic similarity. It is shown that the combination of modal analysis techniques and cumulative damage theory provides a feasible design synthesis methodology for representative test rigs.
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A study was carried out of 45 migrainous patients with visually induced migraine (VIM), and 25 migrainous students, each having an age and sex matched control. The study utilised questionnaires, interviews, electroencephalography (EEG) and visual evoked potentials (VEP). The experimental work and analysis was carried out in the Neuropsychology Unit in collaboration with the Birmingham Migraine Clinic, over a period of five years. The study suggests: 1. The literature on a possible relationship between migraine and epilepsy hitherto published is unreliable (supporting evidence is given). 2. That a much greater precision is needed in defining migraine for research purposes. 3. A revised methodology for the selection of controls is needed and this is proposed. 4. That despite what are now seen to be superficial similarities, there are clear distinctions of a fundamental nature between photo-sensitive epilepsy (PSE) and VIM. 5. Caution be used when taking headache as a symptom, since many of the precipitants of migrainous headache can also precipitate non-migrainous headache (NMH). 6. The list of visual precipitants of migraine is expanded (particularly flicker and pattern). 7. That colour (principally red) is a previously unreported precipitant of migraine. 8. The extended range of responses to flicker (the 'H' response) has no significant difference in its frequency of occurrence in patients and normal controls, which contradicts previous literature. 9. The mechanisms thought to underlie migraine serve to explain previously unexplained EEG findings. 10. Further research is needed and proposed.
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We investigate the pattern-dependent decoding failures in full-field electronic dispersion compensation (EDC) by offline processing of experimental signals, and find that the performance of such an EDC receiver may be degraded by an isolated "1" bit surrounded by long strings of consecutive "0s". By reducing the probability of occurrence of this kind of isolated "1" and using a novel adaptive threshold decoding method, we greatly improve the compensation performance to achieve 10-Gb/s on-off keyed signal transmission over 496-km field-installed single-mode fiber without optical dispersion compensation.
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Through direct modeling, a reduction of pattern-dependent errors in a standard fiber-based transmission link at 40 Gbits/s rate is demonstrated by application of a skewed data pre-encoding. The trade-off between the improvement of the bit error rate and the loss in the data rate is examined.
Resumo:
Through modelling of direct error computation, a reduction of pattern- dependent errors in a standard fiber-based transmission link at 40 Gb/s rate is demonstrated by application of a skewed data pre-encoding. The trade-off between the bit-error rate improvement and the data rate loss is examined.
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This article analyzes the role of expert witness testimony in the trials of social movement actors, discussing the trial of the "Kingsnorth Six" in Britain and the trials of activists currently mobilising against airport construction at Notre Dame des Landes in western France. Though the study of expert testimony has so far overwhelmingly concentrated on fact-finding and admissibility, the cases here reveal the importance of expert testimony not simply in terms of legal argument, but in "moral" or political terms, as it reflects and constitutes movement cognitive praxis. In the so-called climate change defence presented by the Kingsnorth Six, I argue that expert testimony attained a "negotiation of proximity," connecting different types of contributory expertise to link the scales and registers of climate science with those of everyday understanding and meaning. Expert testimony in the trials of activists in France, however, whilst ostensibly able to develop similar bridging narratives, has instead been used to construct resistance to the airport siting as already proximate, material, and embedded. To explain this, I argue that attention to the symbolic, as well as instrumental, functions of expert testimony reveals the crucial role that collective memory plays in the construction of both knowledge and grievance in these cases. Collective memory is both a constraint on and catalyst for mobilisation, defining the boundaries of the sayable. Testimony in trials both reflects and reproduces these elements and is a vital explanatory tool for understanding the narrativisation and communication of movement identities and objectives. © 2013 The Author. Law & Policy © 2013 The University of Denver/Colorado Seminary.
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Natural History filmmaking has a long history but the generic boundaries between it and environmental and conservation filmmaking are blurred. Nature, environment and animal imagery has been a mainstay of television, campaigning organisations and conservation bodies from Greenpeace to the Sierra Club, with vibrant images being used effectively on posters, leaflets and postcards, and in coffee table books, media releases, short films and viral emails to educate and inform the general public. However, critics suggest that wildlife film and photography frequently convey a false image of the state of the world’s flora and fauna. The environmental educator David Orr once remarked that all education is environmental education, and it is possible to see all image-based communication in the same way. The Media, Animal Conservation and Environmental Education has contributions from filmmakers, photographers, researchers and academics from across the globe. It explores the various ways in which film, television and video are, and can be, used by conservationists and educators to encourage both a greater awareness of environmental and conservation issues, and practical action designed to help endangered species. This book is based on a special issue of the journal Environmental Education Research.
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This article addresses the reluctance of mainstream corporate and commercial media to critically address major environmental and conservation issues. The resulting public pedagogy largely reproduces the neoliberal ideology informing much conservation practice and discourse. Nonetheless, the media retains an unrealised critical educative potential that needs to be drawn upon by critical media practitioners and educators. To do this, educators need to be cognisant of the phenomenological experience of spectatorship, the aesthetic form and relational contexts of media consumption, production and informal learning. Referring to the work of Vivian Sobchack, Henry Giroux, Pierre Bourdieu and Gilles Deleuze, the article argues that if critical practitioner-educators apply an analytic framework informed by critical realism, counter-hegemonic elements found within corporate and independent media productions and conservation initiatives may be rearticulated and re-presented in a more positive manner. For this to occur, critical media practitioners-educators need to recognise that feasible political and normative alternatives are both available and practically possible. The article ends by discussing some relatively recent non-fiction productions that express a commonality between human and non-human animals and so form the basis of a critical environmental education-media practice.
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In this article we envision factors and trends that shape the next generation of environmental monitoring systems. One key factor in this respect is the combined effect of end-user needs and the general development of IT services and their availability. Currently, an environmental (monitoring) system is assumed to be reactive. It delivers measurement data and computational results only if the user explicitly asks for it either by query or subscription. There is a temptation to automate this by simply pushing data to end-users. This, however, leads easily to an "advertisement strategy", where data is pushed to end-users regardless of users' needs. Under this strategy, the mere amount of received data obfuscates the individual messages; any "automatic" service, regardless of its fitness, overruns a system that requires the user's initiative. The foreseeable problem is that, unless there is no overall management, each new environmental service is going to compete for end-users' attention and, thus, inadvertently hinder the use of existing services. As the main contribution we investigate the nature of proactive environmental systems, and how they should be designed to avoid the aforementioned problem. We also discuss how semantics, participatory sensing, uncertainty management, and situational awareness link to proactive environmental systems. We illustrate our proposals with some real-life examples.
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The existing body of knowledge has generally supported that organizational culture plays a significant role in shaping group identity, work pattern, communication schemes, and interpersonal relations; all of these cultural elements are important organizational factors that shape workplaces and operational routines. In the context of emerging information technology, it has also been suggested that organizational culture could affect IT implementation and management. However, little is known about how emerging information technology shapes organizational culture, which in turn helps reshape the organization as a whole. The purpose of this paper is thus to build empirical understanding of how IT in general and emerging wireless networks in particular reshapes organizational culture. Case studies conducted in two hospitals situated in southwest U.S.A. illustrated that the implementation of wireless networks indeed helped shape and/or reshape organizational culture in the healthcare sector and in turn enhance healthcare organizations’ competitiveness in the marketplace. For IT managers and practitioners in healthcare institutions, effective strategy to plan and manage emerging ITs such as wireless networks will thus have long-term implications on cultivating organizational culture that could eventually reshape workplace and competitiveness.
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