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461.
Freeze/thaw and pH effects on freshwater dissolved organic matter fluorescence and absorbance properties from a number of UK locations 总被引:2,自引:0,他引:2
The UV-visible and fluorescence excitation-emission matrix spectrophotometric properties of dissolved organic matter (DOM) were compared for the effects of both pH and freeze/thaw on a wide range of freshwater DOM samples from the United Kingdom. It was observed that the spectrophotometric properties of our freshwater samples were sensitive to pH and that the recorded change varies with fluorescence and absorbance intensity, DOC concentration and the wavelength observed. Large and variable responses to pH were particularly severe at extremes of pH, but within the natural levels typically observed in freshwaters the response to pH was limited. For the same sample set large and variable responses were observed when subjected to freeze/thaw. From our data, knowledge of the original properties cannot be used to determine the amount of change that will occur with freezing and subsequent thawing. It is therefore recommended that in future research, to maintain the natural signal of the DOM, analysis is conducted at natural pH and without freezing to facilitate ease of comparison between studies. Our results also have implications for studies that utilise spectrophotometric techniques to investigate long-term trends in dissolved organic carbon in rivers. Spectrophotometric parameters from upland derived samples show varied responses of samples to pH and there is clear potential to complicate trends in the interpretation of long-term water colour data if pH is changing over time in a system or if samples are treated with different storage protocols with respect to acidification and freezing. 相似文献
462.
Peter Francis Sandrine Balbo Lucy Firth 《Universal Access in the Information Society》2009,8(3):123-135
People with cognitive disorders, such as autism or Asperger’s syndrome, face many barriers when being involved in the co-design
of information and communications technologies (ICT). Cognitive disorders may require that co-design techniques be modified
to fit with individual abilities. Up until recently, with technology design, purpose and use being in the hands of ‘experts’
there was little opportunity for customisation. However, ICT bring together various threads that make open many new possibilities.
Not only are technologies cheaper, more powerful and more available than ever, but now parents, support agencies and people
with autism spectrum disorders expect information technologies to be part of their worlds, and they have the capacity to participate
in co-design for customisation. However, co-design techniques have not evolved to the extent that they capture this potential
democratisation of the ICT. This paper reports on an investigation of the potential to develop a set of guidelines for co-design
techniques to enable people with autism spectrum disorders to participate in ICT design. 相似文献
463.
In this article, a reconfigurable cross parasitic antenna is proposed to achieve complete azimuthal beam scanning and tunable beamwidth in the E‐ and H‐plane. The antenna consists of a square‐shaped driven element and four size‐tunable parasitic elements placed on each side of the driven element. Each tunable parasitic element is composed of a hexagonal slot loaded with two varactor diodes. The tunable parasitic element shows dual‐resonance behavior and hence its effective electrical size can be controlled with respect to the driven element. The radiated beam of the cross antenna is continuously scanned in the elevation plane from θ = 0° to 10.8°, 0° to 32.4°, and 0° to 40° in ? = (0°, 180°), (45°, 135°, 225°, 315°), and (90°, 270°) planes, respectively. Moreover, the 3‐dB beamwidth of the cross antenna is continuously tuned from 65° to 152° and from 64° to 116° in the E‐ and H‐plane, respectively. The antenna shows good impedance matching in all the operating modes with ?10 dB bandwidth from 2.43 to 2.47 GHz. A prototype of the antenna is fabricated to experimentally verify the simulated reflection and radiation characteristics. 相似文献
464.
Lucy V. Katz 《Alternatives to the High Cost of Litigation》2008,26(11):206-209
In the second of two parts, Lucy V. Katz , of Fairfield, Conn., provides more on the state of the law of mediation enforcement, and includes a sample mediation clause suitable for adaptation into your contracts. 相似文献
465.
By the year 2050, 67% of the global population will be living in cities where water demand is projected to outstrip supply. This shortage calls for identifying ways through which urban residents and commercial interests can adapt to water stress. As commercial buildings contribute significantly to water consumption in cities, building facilities managers (BFMs) have a significant role in formulation and implementation of the adaptation approaches. Their perceptions of alternative water sources, including reclaimed water, are, therefore, important. In this study, the perceptions of 40 BFMs on reclaimed water use in buildings were analyzed using Q-methodology. Analysis correlated the responses of different people, factoring out the groups of people who hold similar viewpoints. Results showed that participants could be categorized under four factors. Participants in Factor 1 perceived reclaimed water as being healthy and a worthy investment. Those in Factor 2, however, had negative perceptions and did not trust local governments to appropriately manage the treatment process, thus presenting health concerns. They also found reclaimed water repulsive. Participants in Factor 3 were also less willing to adopt reclaimed water, but felt that its use for non-potable purposes would be acceptable. The final group, those in Factor 4 focused more on the cost efficiency and sustainability of reclaimed water, finding it acceptable on those grounds. However, they thought that decisions on its use should be the building owners' prerogative rather than the BFMs. The implications of these findings with respect to encouraging reclaimed water use in commercial office buildings are discussed. 相似文献