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排序方式: 共有308条查询结果,搜索用时 46 毫秒
241.
Gillian Ysart Patrick Miller Helen Crews Paul Robb Malcolm Baxter Christian De L'Argy Simon Lofthouse Christine Sargent Nigel Harrison 《Food Additives & Contaminants》1999,16(9):391-403
Dietary exposures of consumers to 30 elements (aluminium, antimony, arsenic, barium, bismuth, boron, cadmium, calcium, chromium, cobalt, copper, germanium, gold, iridium, iron, lead, lithium, manganese, mercury, molybdenum, nickel, palladium, platinum, rhodium, ruthenium, selenium, strontium, thallium, tin and zinc) estimated from the UK 1994 Total Diet Study are reported, and compared with those from previous UK Total Diet Studies and those from other countries. Dietary exposure estimates were generally low and, where comparisons are possible, similar to those from other countries and below the relevant Provisional Tolerable Weekly Intakes and Provisional Maximum Tolerable Daily Intakes. For most of those elements included in previous UK Total Diet Studies, dietary exposures have declined. 相似文献
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Thermally Stable Silver Nanowire–Polyimide Transparent Electrode Based on Atomic Layer Deposition of Zinc Oxide on Silver Nanowires 下载免费PDF全文
Dustin Chen Jiajie Liang Chao Liu Gillian Saldanha Fangchao Zhao Kwing Tong Jiang Liu Qibing Pei 《Advanced functional materials》2015,25(48):7512-7520
The performance of a flexible transparent conductive electrode with extremely smooth topography capable of withstanding thermal processing at 300 °C for at least 6 h with little change in sheet resistance and optical clarity is reported. In depth investigation is performed on atomic layer deposition (ALD) deposited ZnO on Ag nanowires (NWs) with regard to thermal and atmospheric corrosion stability. The ZnO coated nanowire networks are embedded within the surface of a polyimide matrix, and the <2 nm roughness freestanding electrode is used to fabricate a white polymer light emitting diode (PLED). PLEDs obtained using the ZnO‐AgNW‐polyimide substrate exhibit comparable performance to indium tin oxide (ITO)/glass based devices, verifying its efficacy for use in optoelectronic devices requiring high processing temperatures. 相似文献
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In order to make timely and effective decisions, businesses need the latest information from data warehouse repositories. To keep these repositories up-to-date with respect to end user updates, near-real-time data integration is required. An important phase in near-real-time data integration is data transformation where the stream of updates is joined with disk-based master data. The stream-based algorithm MESHJOIN (Mesh Join) has been proposed to amortize disk access over fast streams. MESHJOIN makes no assumptions about the data distribution. In real-world applications, however, skewed distributions can be found, such as a stream of products sold, where certain products are sold more frequently than the remainder of the products. The question arises is how much does MESHJOIN lose in terms of performance by not adapting to data skew. In this paper we perform a rigorous experimental study analyzing the possible performance improvements while considering typical data distributions. For this purpose we design an algorithm Extended Hybrid Join (X-HYBRIDJOIN) that is complementary to MESHJOIN in that it can adapt to data skew and stores parts of the master data in memory permanently, reducing the disk access overhead significantly. We compare the performance of X-HYBRIDJOIN against the performance of MESHJOIN. We take several precautions to make sure the comparison is adequate and focuses on the utilization of data skew. The experiments show that considering data skew offers substantial room for performance gains that cannot be found in non-adaptive approaches such as MESHJOIN. We also present a cost model for X-HYBRIDJOIN, and based on that cost model, the algorithm is tuned. 相似文献
247.
Francis S. Magbanua Colin R. Townsend Kimberly J. Hageman Katharina Lange Gavin Lear Gillian D. Lewis Christoph D. Matthaei 《Water research》2013
Pesticides and deposited fine sediment have independently been associated with changes in relative abundance and species richness in aquatic ecosystems, but the interplay between these two stressors in agricultural streams is poorly understood. A 28-day experiment in outdoor stream mesocosms examined the effects of four levels each of fine sediment coverage (0, 25, 75, 100%) and glyphosate-based herbicide concentration (0, 50, 200, 370 μg/L) on periphyton communities (algae and bacteria) in a fully factorial, repeated-measures design. Our aims were to determine whether (i) increased levels of sediment and glyphosate had individual and/or additive effects, (ii) increased sediment reduced the toxicity of glyphosate (antagonistic multiple stressor interaction), or (iii) sediment-adsorbed glyphosate prolonged the effects of exposure (synergistic interaction). We also assigned all algal taxa to three ecological guilds (low-profile, high-profile and motile growth forms) and separately determined their responses to the treatments. As individual stressors, sediment addition affected all algal community-level metrics, whereas glyphosate addition only affected algal community evenness. Bacterial taxon richness was unaffected by either stressor. In combination, however, significant overall sediment by glyphosate interactions were detected, demonstrating synergistic (algal evenness, high-profile and motile guilds) or antagonistic effects (low-profile guild). Our experiment underscores the importance of considering both structural and functional indicators, including algal guild representation, when assessing the mechanisms by which periphyton communities respond to multiple stressors. 相似文献
248.
Gillian Greenhill 《History of Photography》2013,37(2):113-120
Abstract An interesting and little-discussed body of photographic work is connected with the circle of Victor Hugo during the years of his exile on the island of Jersey in the English Channel, from 1852 to 1855. These works are now dispersed; a n~umber of them are in Paris, in the Museé de la Maison de Victor Hugo and in the Bibliothèque Nationale, another survives in the archivcs of the International Museum of Photography at the George Eastman House, Rochester, New York; and various other examples exist in private collections. The Jersey photographs are the result of a joint effort by Charles Hugo, the poet's son, and his friend, Auguste Vacquerie. 相似文献
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Skotko Brian G.; Kensinger Elizabeth A.; Locascio Joseph J.; Einstein Gillian; Rubin David C.; Tupler Larry A.; Krendl Anne; Corkin Suzanne 《Canadian Metallurgical Quarterly》2004,18(4):756
Researchers currently debate whether new semantic knowledge can be learned and retrieved despite extensive damage to medial temporal lobe (MTL) structures. The authors explored whether H. M., a patient with amnesia, could acquire new semantic information in the context of his lifelong hobby of solving crossword puzzles. First, H. M. was tested on a series of word-skills tests believed important in solving crosswords. He also completed 3 new crosswords: 1 puzzle testing pre-1953 knowledge, another testing post-1953 knowledge, and another combining the 2 by giving postoperative semantic clues for preoperative answers. From the results, the authors concluded that H. M. can acquire new semantic knowledge, at least temporarily, when he can anchor it to mental representations established preoperatively. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献