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21.
This article presents a method for colour measurements directly on printed half‐tone multicoloured pictures. The article introduces the concept of colour impression. By this concept we mean the CMY or CMYK vector (colour vector), which lives in the three‐ or four‐dimensional space of printing inks. Two factors contribute to values of the vector components, namely, the percentage of the area covered by cyan, magenta, yellow, and black inks (tonal values) and ink densities. The colour vector expresses integrated information about the tonal values and ink densities. Values of the colour vector components increase if tonal values or ink densities rise and vice versa. If, for some primary colour, the ink density and tonal value do not change, the corresponding component of the colour vector remains constant. If some reference values of the colour vector components are set from a preprint, then, after an appropriate calibration, the colour vector directly shows how much the operator needs to raise or lower the cyan, magenta, yellow, and black ink densities in order to correct colours of the picture being measured. The values of the components are obtained by registering the RGB image from the measuring area and then transforming the set of registered RGB values to the triplet or quadruple of CMY or CMYK values, respectively. Algorithms based on artificial neural networks are used for performing the transformation. During the experimental investigations, we have found a good correlation between components of the colour vector and ink densities. © 1999 John Wiley & Sons, Inc. Col Res Appl, 24, 185–196, 1999  相似文献   
22.
As part of a large European Union (EU)-funded comparative toxicology and human epidemiology study, EU-Compare, a selection of organohalogen compounds (OHCs) was analyzed in maternal serum, collected at the 35th week of pregnancy, and in cord serum of a number of their infants to determine maternal concentrations and to investigate the extent of transplacental transfer of these compounds. Eight neutral OHCs were analyzed: one polychlorinated biphenyl (PCB: CB-153),4,4'-DDE, five polybrominated diphenyl ethers (PBDEs: BDE-47, BDE-99, BDE-100, BDE-153, and BDE-154), and hexabromocyclododecane (HBCDD). Five phenolic OHCs were analyzed: three hydroxylated PCBs (40H-CB-107, 40H-CB-146, and 40H-CB-187), one hydroxylated PBDE (60H-BDE-47), and pentachlorophenol (PCP). All OHCs, except 60H-BDE-47, were present in maternal and cord serum. The historically identified OHCs showed the highest concentration: 4,4'-DDE (median value 89 ng/g lipid in maternal serum and 68 ng/g lipid in cord serum) and PCP (median value 970 pg/g serum in maternal serum and 1500 pg/g serum in cord serum). HBCDD and the PBDEs were present at much lower concentrations. We conclude that OHCs are present in the serum of pregnant women, and all compounds tested are transferred over the placenta. Because transfer is occurring at a critical stage of infant development, investigation of the health impact is urgent.  相似文献   
23.
Rivers networks represent hierarchical dendritic habitats within terrestrial landscapes and differences in connectivity and land use influence dispersal, and consequently biodiversity patterns. We, therefore, measured variation in water chemistry and fish abundance and related these to a number of landscape characteristics (e.g., wetland, urban, wooded, and agricultural) in the River Klarälven and its 30 permanently flowing tributaries. We hypothesized that these environmental attributes would differ between tributary and main stem habitat and that these differences would be driven by landscape attributes including land use. We found considerable intertributary variation in temperature and nutrient levels, and between the tributaries and the main stem. Generally, water temperature was lower in the tributaries, whereas nutrient levels were higher in the tributaries. The lower water temperature has implications for coldwater fishes, and we found two fishes, burbot and lamprey, associated with coldwater tributaries. We also found an inverse relationship between water quality and anthropogenic land use. Protecting tributaries with low anthropogenic impact will likely become increasingly important with ongoing global warming as they can function as thermal refugia for coldwater fishes. Hence, this study underscores the need to evaluate water courses at regional scales to identify spatial refuges and ensure connectivity.  相似文献   
24.
Domestic energy use accounts for more than a quarter of CO2 emissions in the UK. Traditional approaches to energy reduction look at direct emissions savings, and recommend insulation and efficiency as more cost-effective than microgeneration. However, microgeneration has indirect, ‘soft’ benefits and could play a significant role in emissions reduction. Current uptake of microgeneration in the UK is low, with various barriers—economic, technical, cultural, behavioural and institutional—both to uptake and to maximising energy and emissions savings once installed. Subsidies and spreading information alone do not guarantee maximising uptake, and even if successful, this is not enough to maximise savings. The industry focuses on maximising sales, with no incentives to ensure best installations and use; householders do not have access to the best information, and user behaviour does not maximise energy and emission savings. This is related to a broader state of socio-technical ‘lock-in’ in domestic energy use; there’s a lack of connection between personal behaviour and energy consumption, let alone global climate change. This suggests that a major cultural–behavioural shift is needed to reduce energy/emissions in the home. Transition theory and strategic niche management provide insights into possible systemic change and a suitable framework for future policies, such as supporting a variety of radically innovative niches, both technological and social. Microgeneration, properly employed, has the potential to play a part in such a transition by increasing awareness and energy literacy and empowering people to seriously engage in energy debates as producers, as well as consumers, of energy. This deeper understanding and heightened responsibility are crucial in a shift toward bottom-up emission-reducing behaviour change and better acceptance of top-down energy-saving policy measures, as part of a new domestic energy paradigm. The implications for policy are that, as well as supporting the technologies, it needs to support existing niches and to develop new niche experiments. Policy needs to consider how to promote empowerment and responsibility and support or even develop new energy sector models; this will involve a range of stakeholders and multiple governance levels, not just national incentive schemes.  相似文献   
25.
Brominated flame retardants in serum from U.S. blood donors   总被引:1,自引:0,他引:1  
Serum samples collected in 1988 from U.S. blood donors were analyzed for polybrominated diphenyl ethers (PBDEs) and polychlorinated and polybrominated biphenyls (PCBs and PBBs). The levels of the PBDEs are reported for the first time in serum from the U.S. population. The median concentrations and range of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47); 2,2',4,4',5,5'-hexabromodiphenyl ether (BDE-153); 2,2',3,4,4',5',6-heptabromodiphenyl ether (BDE-183); and decabromodiphenyl ether (BDE-209) were 1.3 (<0.8-49); 0.54 (0.13-3.1); 0.24 (0.12-1.8); and <1 (<1-35) pmol/g lipid weight (l.w.), respectively. In addition we also measured detectable levels of nine additional PBDE congeners in many of the serum samples. The median concentrations and ranges of 2,2',4,4',5,5'-hexachloro- and hexabromobiphenyl (CB-153 and BB-153) were 190 (21-2600) and 19 (4.2-84) pmol/g l.w. The levels of PBDEs and CB-153 found in the U.S. samples were similar to background levels reported in the serum of Swedish hospital cleaners collected 10 years later, i.e., 1997. The BB-153 congener measured in the U.S. samples was not found in the Swedish samples. The difference in exposure to this congener could not be assessed in this study, although might be related to the 1973 BB-153 (FireMaster BP-6) animal and human contamination incident in the State of Michigan.  相似文献   
26.
During the second part of the 1990s the Nordic (Denmark, Finland, Norway and Sweden) countries have created a unique multinational market for electricity. This paper aims to analyse the degree of integration of the different national markets that constitute the Nordic electricity market. In particular the Norwegian and Swedish wholesale and retail electricity markets are analysed. The results suggest that the wholesale markets are well integrated. Thus prices differ significantly only during periods with unusually high or low supply of hydropower. However, the retail markets are not integrated to the same degree. Thus retail prices and trade margins differ significantly. Differences in the national electricity market legislation seem to be a key factor behind these differences.  相似文献   
27.
28.
In this paper, we demonstrate full closed-loop control of electrostatically actuated double-gimbaled MEMS mirrors and use them in an optical cross-connect. We show switching times of less than 10 ms and optical power stability of better than 0.2 dB. The mirrors, made from 10-/spl mu/m-thick single-crystal silicon and with a radius of 400-450 /spl mu/m, are able to tilt to 8/spl deg/ corresponding to 80% of touchdown angle. This is achieved using a nonlinear closed-loop control algorithm, which also results in a maximum actuation voltage of 85 V, and a pointing accuracy of less than 150 /spl mu/rad. This paper will describe the MEMS mirror and actuator design, modeling, servo design, and measurement results.  相似文献   
29.
Inspection of the amino acid-base interactions in protein-DNA complexes is essential to the understanding of specific recognition of DNA target sites by regulatory proteins. The accumulation of information on protein-DNA co-crystals challenges the derivation of quantitative parameters for amino acid-base interaction based on these data. Here we use the coordinates of 53 solved protein-DNA complexes to extract all non-homologous pairs of amino acid-base that are in close contact, including hydrogen bonds and hydrophobic interactions. By comparing the frequency distribution of the different pairs to a theoretical distribution and calculating the log odds, a quantitative measure that expresses the likelihood of interaction for each pair of amino acid-base could be extracted. A score that reflects the compatibility between a protein and its DNA target can be calculated by summing up the individual measures of the pairs of amino acid-base involved in the complex, assuming additivity in their contributions to binding. This score enables ranking of different DNA binding sites given a protein binding site and vice versa and can be used in molecular design protocols. We demonstrate its validity by comparing the predictions using this score with experimental binding results of sequence variants of zif268 zinc fingers and their DNA binding sites.  相似文献   
30.
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